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Disease Issues
How serious a problem is influenza in the U.S.?
Influenza is the most frequent cause of death from a vaccine-preventable disease in the United States. In a study of influenza seasons from 1976-1977 through 2006-2007, the estimated number of annual influenza-associated deaths from respiratory and circulatory causes ranged from a low of 3,349 (1985-1986 season) to a high of 48,614 (2003-2004 season), with an average of 23,607 influenza-associated deaths. In addition to fatalities, seasonal influenza is also responsible for more than 200,000 hospitalizations per year. Rates of infection from seasonal influenza are highest among children, but the risks for complications, hospitalizations, and deaths are higher among adults ages 65 years and older, children younger than 5 years, and people of any age who have medical conditions that place them at increased risk for complications from influenza.
A novel H1N1 virus was first detected in March of 2009 and quickly spread to pandemic levels. In the U.S., it is estimated that approximately 43-89 million persons became ill with 2009 pandemic H1N1 from April 2009 to April 2010. The virus also resulted in significant hospitalizations and deaths among children, adults 19-65 years, obese persons, and pregnant and post-partum women. The pandemic virus has continued to circulate.
The 2013–2014 influenza season peaked during last week of December 2013. The predominant virus was the 2009 pandemic H1N1 virus. Among hospitalized persons 57% were 18-64 years old but the highest rates of hospitalization were among persons ages 65 years and older (88 per 100,000) and 50-64 years (54 per 100,000). There were 96 laboratory-confirmed influenza-related pediatric deaths reported from 30 states; 44% of influenza-related deaths were among children younger than 23 months.
Where can I get information on influenza and its surveillance?
Information regarding influenza surveillance is available October through May from the CDC influenza website at www.cdc.gov/flu/weekly/fluactivitysurv.htm. In addition, periodic updates about influenza are published in the MMWR. State and local health departments should be consulted regarding availability of influenza vaccine, access to vaccination programs, information about state or local influenza activity, and for reporting influenza outbreaks and receiving advice regarding their control.
Vaccine Recommendations Back to top
What influenza vaccines will be available during the 2014–15 influenza season?
Multiple manufacturers will produce influenza vaccine for the U.S. market for the 2014–2015 season. Inactivated, recombinant (inactivated) and live attenuated vaccines will be produced using egg-based, cell culture-based, and recombinant technologies. The live attenuated vaccine and some of the inactivated influenza vaccines will be quadrivalent (contain four strains of influenza virus) rather than trivalent (three strains). A complete listing of influenza vaccine products is available at www.immunize.org/catg.d/p4072.pdf.
Abbreviations will help identify the different types of vaccines available. The abbreviations include IIV for inactivated influenza vaccine, RIV for recombinant hemagglutinin influenza vaccine, LAIV for live, attenuated influenza vaccine, and ccIIV for cell culture-based IIV. The addition of either a 3 or a 4 at the end of an abbreviation indicates if the vaccine is trivalent or quadrivalent (for example, IIV3, RIV3, IIV4, LAIV4).
What are the differences in trivalent and quadrivalent influenza vaccines?
Influenza vaccine produced for the 2014–2015 season will be either trivalent (three components) or quadrivalent (4 components). Both types of vaccine contain two A viruses and one B virus: The components of the 2014–2015 vaccines are the same as those contained in the 2013–2014 vaccines:
  A/California/7/2009 (H1N1)pdm09-like virus
A(H3N2) virus antigenically like the cell-propagated prototype virus A/Victoria/361/2011
B/Massachusetts/2/2012-like virus
The quadrivalent vaccine will contain these three viruses, plus a B/Brisbane/60/2008-like virus.
If quadrivalent vaccine includes one additional strain, why isn't it preferred for use over trivalent vaccines?
Even though both influenza B viruses are likely to cause disease during an influenza season, traditionally experts have to choose between the two very different B viruses to include with the two A viruses based on which type of B virus is expected to predominate. This can be difficult to predict. The quadrivalent vaccine includes both B viruses. However, while quadrivalent vaccines may eventually replace trivalent vaccines, during the coming season the quantity of quadrivalent vaccine may be limited. Consequently, except for children 2 through 8 years of age (see below), ACIP does not express a preference for use of one type of influenza vaccine over another type (that is, live over inactivated, or quadrivalent over trivalent) for those for whom more than one type of vaccine is indicated and available.
If the components of the 2014-2015 influenza vaccine are the same as last year do people who received the vaccine last year need to be revaccinated.
Yes. Antibody levels decline after vaccination. Vaccination during this influenza season will boost immunity and improve protection from influenza virus infection this season..
Is it acceptable to administer a dose of the quadrivalent influenza vaccine to a patient who has already received the trivalent vaccine? We’ve had a few patients request this.
No. ACIP does not recommend that anyone receive more than one dose of influenza vaccine in a season, except for certain children age 6 months through 8 years for whom two doses are recommended.
Who is recommended to get vaccinated against influenza?
Beginning with the 2010–11 vaccination season, ACIP recommends annual vaccination for all people ages 6 months and older who do not have a contraindication to the vaccine.
We're glad that CDC has made a universal influenza vaccination recommendation to vaccinate everyone 6 months and older. Would you tell us how this came about?
Prior to the 2010-11 vaccination season, only children ages 6 months through 18 years and adults age 50 years and older were universally recommended for vaccination; recommendations for adults ages 19 through 49 years were targeted to people with specific risk factors, although other adults could be vaccinated if they wanted protection. Collectively, these targeted risk groups made up 85% of the U.S. population. During the 2009 H1N1 outbreak, additional risk groups were identified, such as obese individuals. The recommendation made by ACIP in February 2010 for universal vaccination simplifies previous recommendations, making it easier for healthcare providers to determine whom to vaccinate. The universal recommendation also makes it easier for patients to remember to get vaccinated every year.
When should influenza vaccine be given?
You can begin offering vaccine as soon as vaccine becomes available. Early vaccination of children younger than age 9 years who need 2 doses of vaccine can be helpful in assuring routine second doses before the influenza season begins.
We have noticed that CDC recommends that we begin vaccinating with seasonal influenza vaccine as early as September or even earlier. Does protection from seasonal influenza vaccine decline or wane within 3 or 4 months of vaccination? Should I wait until October or November to vaccinate my elderly or medically frail patients?
CDC recommends that seasonal influenza vaccine be administered to all age groups as soon as it becomes available. Antibody to seasonal inactivated influenza vaccine declines in the months following vaccination. However, antibody level at a point several months after vaccination does not necessarily correlate with clinical vaccine effectiveness. There are no studies that compare vaccine effectiveness according to the month when the vaccination was given. The authors of a review on antibody declines among the elderly after vaccination reported, "In conclusion, we found no compelling evidence for more rapid decline of the influenza vaccine-induced antibody response in the elderly, compared with young adults, or evidence that seroprotection is lost at 4 months if it has been initially achieved after immunization." (See Skowronski, et al., Rapid Decline of Influenza Vaccine-Induced Antibody in the Elderly: Is it Real, or Is It Relevant? Journal of Infectious Diseases 2008;197:490-502).In addition, there is a lack of evidence for late-season outbreaks among vaccinated persons that can be attributed to waning immunity.
How late in the season can I vaccinate my patients with influenza vaccine?
Peak influenza activity does not generally occur until February. Providers are encouraged to continue vaccinating patients throughout the influenza season, including into the spring months (for example, through May), as long as they have vaccine in the refrigerator and unvaccinated patients in their office.
Because influenza occurs in many areas of the world during April through September, vaccine should be given to travelers who missed vaccination in the preceding fall and winter. Another late season use of vaccine is for children younger than age 9 years who needed 2 doses of vaccine but failed to get their second dose. For each of these situations, vaccine can be given through the month of June since most injectable influenza vaccine has a June 30 expiration date.
Which travelers are recommended to be vaccinated?
Healthcare providers should vaccinate any person who failed to get vaccinated in the previous vaccination season and who wants to reduce their risk of acquiring influenza during their upcoming travel, particularly if they are at high risk for influenza-related complications. This includes persons who are traveling to the tropics, traveling with organized tourist groups at any time of year, or traveling to the Southern Hemisphere during April-September.
If a patient received a dose of influenza vaccine in June (for example, for international travel), how long should the patient wait before getting vaccinated with the next season's flu vaccine?
There should be a minimum of 4 weeks between the doses in such situations.
I have a 24-year-old patient who received influenza vaccine in Colombia, South America, on June 19, 2014. Does he need to get another influenza vaccine during the current U.S. influenza season?
Yes. The person should be revaccinated with the 2014–15 U.S. vaccine, even though the strains in the U.S. vaccine are the same as the 2014 Southern hemisphere vaccine. Vaccination again with the current vaccine will help assure protection through the influenza season into next spring.
We are always concerned that there won't be enough vaccine to vaccinate our patients in the fall. What can we do to be assured that we've done all that we possibly can to avoid this type of situation?
It is never too early to begin planning for the coming fall's influenza vaccination program. The most important thing you can do initially is to place your order for vaccine from your usual source. Some manufacturers often stop taking pre-orders in mid-May. Be sure to include vaccine for pediatric patients needing two doses and also for your facility's healthcare workers as part of your overall campaign.
Why do people who received influenza vaccine in one year still need to get vaccinated in the next year when the viruses haven't changed?
Although the strains may sometimes be the same as in the previous year's vaccine, you should NOT use the previous season's vaccine you might still have in your refrigerator. Most influenza vaccine distributed in the northern hemisphere expires on June 30 after each season; expired vaccine should NEVER be administered. Secondly, antibody titers that persons might have achieved from the previous year's vaccination will have waned and need to be boosted with a dose of the current year's vaccine.
If an unvaccinated patient who has just recovered from a diagnosed case of influenza comes into our clinic, should we vaccinate him?
Yes. Influenza vaccine contains three or four influenza vaccine virus strains; two A viruses and one or two B viruses, which are prepared based on circulating viruses from the previous influenza season. Infection from one virus type does not confer immunity to other types and it would not be unusual to have exposure to more than one type during a typical influenza season, so a person who has recently had influenza will benefit from receipt of a vaccine that contains additional influenza virus strains.
How long does immunity from influenza vaccine last?
Protection from influenza vaccine is thought to persist for a year because of waning antibody and because of changes in the circulating influenza virus from year to year.
Some of my patients refuse influenza vaccination because they insist they "got the flu" after receiving the injectable vaccine in the past. What can I tell them?
There are several reasons why this misconception persists: (1) Less than 1% of people who are vaccinated with the injectable vaccine develop flu-like symptoms, such as mild fever and muscle aches, after vaccination. These side effects are not the same as having influenza, but people confuse the symptoms. (2) Protective immunity doesn't develop until 1–2 weeks after vaccination. Some people who get vaccinated later in the season (December or later) may get influenza shortly afterward. These late vaccinees develop influenza because they were exposed to someone with the virus before they became immune. It is not the result of the vaccination. (3) To many people "the flu" is any illness with fever and cold symptoms. If they get any viral illness, they may blame it on the flu shot or think they got "the flu" despite being vaccinated. Influenza vaccine only protects against certain influenza viruses, not all viruses. (4) The influenza vaccine is not 100% effective, especially in older persons. For more information on this topic, go to: www.cdc.gov/flu/professionals/vaccination/effectivenessqa.htm
Is a Vaccine Information Statement (VIS) only recommended or is it mandatory when administering influenza vaccine?
As of January 1, 2006, the use of a VIS for influenza vaccine given to a child or an adult became mandatory under the National Vaccine Injury Compensation Program. Two VISs are published annually, one for LAIV and one for IIV. Each can be found at www.immunize.org/vis along with many translations.
Are there recommendations for the prevention of institutional outbreaks of influenza?
The most important factor in preventing outbreaks is annual vaccination of all occupants of the facility, and all persons in the facility who share the same air as the high-risk occupants. Groups that should be targeted include physicians, nurses, and other personnel in hospitals and outpatient settings who have contact with high-risk patients in all age groups, and providers of home care to high-risk persons (for example, visiting nurses, volunteers).
What is the recommended interval for receiving influenza vaccine after an allergy injection?
Vaccines can be administered at any time before or after administration of an "allergy injection."
We are trying to provide influenza vaccination to all eligible patients during their stay in our hospital. If a patient does not remember if he or she has already received the vaccine this season, should we go ahead and vaccinate?
If a patient or family member cannot remember if the patient received influenza vaccine this season and no record is available, proceed with administering influenza vaccine, even if it might mean an extra dose is given. When a patient reports that they HAVE received influenza vaccine but does not have written documentation, ACIP states that in the specific case of influenza vaccination, patient self-report of being vaccinated should be accepted as evidence of vaccination.
For Children Back to top
Which children should receive influenza vaccine?
ACIP recommends annual influenza vaccination for all children age 6 months and older who do not have a contraindication to the vaccine.
Which influenza vaccines can we give to children?
Among the injectable inactivated influenza vaccines (IIV), only Fluzone (Sanofi) is approved by the FDA for use in children ages 6 through 35 months. However, there are several injectable influenza vaccines that can be given to children age 3 years or older.
The nasal spray live attenuated influenza vaccine (LAIV, FluMist, MedImmune) is approved for healthy children age 2 years and older. You can find information on all influenza vaccines available in the U.S. for the current season and the age groups approved by FDA by going to IAC's handout titled "Influenza Vaccine Products for the 2014–2015 Influenza Season" available at www.immunize.org/catg.d/p4072.pdf.
When immediately available, LAIV is preferred for use in healthy children ages 2 through 8 years who do not have a contraindication or precaution to LAIV. ACIP states this preference because two studies have shown LAIV to be more effective than IIV in preventing influenza in this age group. However, both LAIV and IIV are safe and effective in this age group. If LAIV is not immediately available, IIV should be used. Vaccination should not be delayed in order to procure LAIV.
Does the ACIP preference for use of LAIV in children ages 2 through 8 years include children with asthma?
No. Asthma or a wheezing episode noted in the medical record within the past 12 months is still considered a contraindication to the use of LAIV for children ages 2 through 4 years. For people age 5 years and older, asthma is considered to be a precaution (not a contraindication) for the use of LAIV.
We've heard that ACIP has limited the use of one of the influenza vaccine products for children. Is that true?
Yes. You are referring to Afluria, which is manufactured by bioCSL for the U.S. market. The company’s 2010 Southern Hemisphere influenza vaccine (Fluvax and Fluvax Junior) was associated with increased post-marketing reports of fever and febrile seizures in children predominantly younger than age 5 years as compared to previous years. For this reason, ACIP recommends that Afluria, which is licensed for use in people age 5 years and older, not be used in children younger than age 9 years. ACIP further recommends that Afluria may be administered to children ages 5 through 8 years who are at high risk for influenza complications if there is no other age-appropriate IIV available, after risks and benefits of using this vaccine in this age group have been discussed with the parent or guardian. The vaccine should not be given to children younger than age 5 years. For detailed information, see www.cdc.gov/mmwr/pdf/rr/rr6207.pdf, page 13.
Which children younger than age 9 years will need 2 doses of influenza vaccine in this influenza season?
Children age 6 months through 8 years should receive a second dose 4 weeks or more after the first dose if they 1) are receiving influenza vaccine for the first time, or 2) did not get a total of at least two doses of seasonal influenza vaccine since July 1, 2010. Children in this age group who received at least one dose during the 2013–2014 season need only one dose during the 2014–2015 season.
CDC has developed an alternative approach that may be used with children who have well-documented histories of influenza vaccination (for example, vaccination records maintained in an electronic registry). By this approach, children age 6 months through 8 years need only one dose of vaccine in this season if they have received any of the following: 1) at least one dose of vaccine during the 2013–2014 influenza season; 2) two or more doses of seasonal influenza vaccine since July 1, 2010; 3) two or more doses of seasonal vaccine given before July 1, 2010, and one or more dose of monovalent 2009 H1N1 vaccine; or 4) at least one dose of seasonal vaccine given before July 1, 2010, and at least one dose of seasonal vaccine since July 1, 2010.
For more details about the ACIP recommendations for which children need two doses, see pages 691–7 of "Prevention and Control of Seasonal Influenza with Vaccines" available at www.cdc.gov/mmwr/pdf/wk/mm6332.pdf.
You can also find this information in one of the IAC's handouts – "Guide for Determining the Number of Doses of Influenza Vaccine to Give to Children Ages 6 Months Through 8 Years" (see www.immunize.org/catg.d/p3093.pdf).
When a child needs 2 doses of influenza vaccine, can I give 1 dose of each type (injectable and nasal spray)?
Yes. As long as a child is eligible to receive nasal spray vaccine (i.e., is in the proper age range and health status), it is acceptable to give 1 dose of each type of influenza vaccine. The doses should be spaced at least 4 weeks apart.
Can a child who needs 2 doses of influenza receive 1 dose of quadrivalent vaccine and 1 dose of trivalent vaccine?
Yes. You can give these two vaccines, as long as the 2 doses are appropriately spaced.
If a child receives influenza vaccine at age 34 or 35 months for the first time (0.25 mL dose) and then returns for the second dose at age 37 months, should we give another 0.25 mL dose or should we give the 0.5 mL dose that is indicated for ages 3 and older?
The child should always receive the dose appropriate for his or her age at the time of the clinic visit; at age 37 months that would be 0.5 mL.
A five-year-old child received her second MMR a week ago. How long should she wait before receiving live attenuated influenza vaccine (LAIV)?
LAIV can be administered simultaneously with another live vaccine (for example, MMR, varicella), but if not given at the same time, ACIP recommends waiting four weeks before administering the second live vaccine.
Can a clinic vaccinate children younger than age 3 years with a 0.25 mL dose of influenza vaccine taken from a multidose vial of Fluzone (IIV; sanofi)? The multi-dose vial contains thimerosal as a preservative.
Yes, Fluzone is the only inactivated influenza vaccine licensed for use in children younger than age 3 years. Multidose vials of Fluzone contain a small amount of thimerosal to prevent bacterial and fungal growth in the vials. Thimerosal-containing vaccines are safe to use in children. No scientific evidence indicates that thimerosal in vaccines causes adverse events unless the patient has a severe allergy to thimerosal. However, a few states have enacted legislation that restricts the use of thimerosal-containing vaccines in children. To find out if your state has such restrictions, check with your state immunization program.
For Special Groups Back to top
Is influenza vaccine recommended for pregnant women?
Yes. It is especially important to vaccinate pregnant women because of their increased risk for influenza-related complications. An increased risk of severe influenza infection was also observed in postpartum women (those delivered within the previous 2 weeks) during the 2009–2010 H1N1 pandemic. Vaccination can occur in any trimester, including the first. Only inactivated vaccine should be given to pregnant women.
Why do we vaccinate pregnant women against influenza when it is not recommended to vaccinate infants younger than age 6 months?
ACIP has recommended vaccinating pregnant women with inactivated influenza vaccine since 1997. Pregnant women are a high risk group for complications, hospitalization, and even death from influenza because of the increased physiologic strain of pregnancy on their heart, lungs, and immune system. Vaccination can occur in any trimester, including the first.
Influenza vaccine is not recommended for children younger than age 6 months because it is not approved for this age group. In addition, there are data that indicate that vaccinated pregnant women pass maternal antibodies to the fetus in the last few weeks of pregnancy; this helps protect the young infant against influenza. Vaccinating pregnant women protects women, their unborn babies, and their babies after birth.
Does ACIP recommend one influenza product over another for pregnant women?
Pregnant women can receive any of the inactivated vaccines. They should not be given the live attenuated influenza vaccine.
Can thimerosal-containing vaccine be given to pregnant women?
Yes, unless you live in a state that has enacted legislation restricting use in pregnant women. There is no scientific evidence that thimerosal in vaccines, including influenza vaccines, is a cause of adverse events, unless the patient has a systemic allergy to thimerosal.
A co-worker of mine says we are supposed to give infants preservative-free influenza vaccine. Is this true?
No. CDC and ACIP express no preference for preservative-free vaccine for infants or any other group of vaccine recipients (see "Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP) — United States, 2013-2014" found at www.cdc.gov/mmwr/pdf/rr/rr6207.pdf, page 18).
No scientific evidence exists that thimerosal in vaccines, including influenza vaccines, is a cause of adverse events, unless the patient has a systemic allergy to thimerosal. However, some states have enacted legislation that restricts the use of thimerosal-containing vaccines. Check with your state immunization manager to see if your state is one of them (www.immunize.org/coordinators).
Do diabetics who control their disease with diet need influenza vaccine?
People with a metabolic disease, including diabetes, should receive annual influenza vaccination with the inactivated vaccine.
Is influenza vaccine safe to administer to patients with multiple sclerosis?
Yes. Multiple sclerosis is not a contraindication to any vaccine, including influenza and pneumococcal vaccines. However, these patients should receive inactivated influenza vaccine and not the live, intranasal vaccine.
Does influenza vaccine increase the HIV titer in the blood of people with HIV infection?
Although some studies have demonstrated a transient increase in replication of HIV following inactivated influenza vaccine, other studies have not found this. This temporary increase in HIV titer has not been associated with deterioration in either T-lymphocyte counts or clinical condition. ACIP believes that annual influenza vaccination with inactivated vaccine will benefit many HIV-infected persons.
A study published in 2014 found that the injectable vaccine Fluzone High-Dose (Sanofi) protects people 65 years and older better than standard-dose Fluzone. Does ACIP preferentially recommend use of Fluzone High-Dose for all people age 65 years and older?
Aging decreases the body's ability to develop a good immune response after getting influenza vaccine, which places older people at greater risk of severe illness from influenza. A higher dose of antigen in the vaccine should give older people a better immune response and therefore provide better protection against influenza. However, despite published evidence of better protection from Fluzone High-Dose when compared to standard-dose Fluzone (N Engl J Med 2014; 371:635–45), ACIP has not stated a preference for this vaccine for people age 65 years and older.
May Fluzone High-Dose (sanofi) be administered to patients younger than age 65 years?
No. Fluzone High-Dose is licensed only for people age 65 years and older and is not recommended for younger people. See MMWR, April 30, 2010, available at www.cdc.gov/mmwr/preview/mmwrhtml/mm5916a2.htm for details about the licensure of this vaccine.
Sometimes patients age 65 years and older who have received the standard-dose influenza vaccine hear about the high-dose product (Fluzone High-Dose, sanofi) and want to receive that, too. Is this okay to administer?
No. ACIP does not recommend that anyone receive more than one dose of influenza vaccine in a season except for certain children age 6 months through 8 years for whom two doses are recommended.
Would giving an older patient 2 doses of standard-dose influenza vaccine be the same as administering the high-dose product?
No, and this is not recommended.
If a patient is undergoing treatment for cancer, is it safe to vaccinate her or him against influenza?
People with cancer need to be protected from influenza, and they can and should receive inactivated influenza vaccine (not LAIV) even if they are immunosuppressed. Cancer patients and survivors are at higher risk for complications from flu, including hospitalization and death. Here is a helpful CDC web page on cancer and influenza for patients: www.cdc.gov/cancer/flu.
How soon after bone marrow transplant do we start to vaccinate our patients against influenza?
Inactivated influenza vaccine should be administered beginning at least 6 months after bone marrow transplant and annually thereafter for the life of the patient. A dose of inactivated influenza vaccine can be given as early as 4 months after transplant, but a second dose should be considered in this situation. A second dose is recommended routinely for all children receiving influenza vaccine for the first time. For more information about vaccination of people who receive hematopoietic stem cell transplantation, visit this CDC web page: www.cdc.gov/vaccines/pubs/hemato-cell-transplts.htm.
For Healthcare Workers Back to top
Which healthcare personnel should be vaccinated against influenza?
It is important to vaccinate ALL hospital and outpatient-care personnel, especially those that have direct contact with patients. In addition to physicians and nurses, vaccination in a hospital setting also includes full-time and part-time employees in radiology, laboratories, pharmacy, human resources, facilities management (housekeeping), food services, or laundry. Vaccinate volunteers as well. Others that should be vaccinated are emergency response workers, employees of nursing homes and assisted living programs, and providers of home care.
Which employees of chronic care facilities and nursing homes should be vaccinated against influenza?
All employees of long term care facilities who have any patient contact and do not have a valid contraindication should receive annual influenza vaccination.
What are the ACIP recommendations for influenza vaccination of healthcare personnel?
Because healthcare personnel (HCP) provide care to patients at high risk for complications of influenza, HCP should be considered a high-priority group for receiving vaccination. Achieving high rates of vaccination among HCP will protect staff and their patients, and reduce disease burden and healthcare costs. Vaccination rates of HCP are still too low; CDC conducted an Internet panel survey with 2,348 HCP during April 2–20, 2012, which found that, overall, 66.9% of HCP reported having had an influenza vaccination for the 2011–12 season.
On February 24, 2006, CDC devoted an entire issue of MMWR Recommendations and Reports to influenza vaccination of HCP. These recommendations are summarized in the following points:
All HCP should be educated regarding the benefits of influenza vaccination.
Influenza vaccine should be offered annually to all eligible HCP.
Obtain a signed declination from HCP who decline influenza vaccination.
Monitor HCP influenza vaccination coverage and declination at regular intervals.
Use the level of HCP vaccination coverage as one measure of a patient-safety quality program.
To obtain a copy of these CDC recommendations for healthcare personnel, go to www.cdc.gov/mmwr/preview/mmwrhtml/rr5502a1.htm In addition, in 2011, ACIP published "Immunization of Health-Care Personnel" which includes information about all recommended vaccines (see www.cdc.gov/mmwr/pdf/rr/rr6007.pdf).
What is the Joint Commission's recommendation on vaccinating healthcare workers against influenza?
In January 2007, a new infection control standard of the Joint Commission became effective that requires accredited organizations to offer annual influenza vaccination to staff, volunteers, and licensed independent practitioners who have close patient contact.
Please review which healthcare workers (HCWs) can be given the intranasal live attenuated influenza vaccine (LAIV) and which cannot.
LAIV can be administered to all HCWs for whom it is indicated based on age and health history--except to those who care for severely immunocompromised patients in a protected (reverse air flow) environment. Despite the clarity of this strong recommendation, we have heard that some healthcare facilities erroneously take extreme measures to protect all patients from exposure to someone recently vaccinated with LAIV. Some even restrict visitors from seeing hospitalized patients, allowing only people vaccinated with inactivated influenza vaccine (IIV) to visit. CDC addressed this issue as follows: "Concerns about the theoretic risk posed by transmission of live attenuated vaccine viruses contained in LAIV to patients should not be used to justify preferential use of IIV in health-care settings other than inpatient units that house severely immunocompromised patients requiring protected environments. Some health-care facilities might choose to not restrict use of LAIV in close contacts of severely immunocompromised persons, based on the lack of evidence for transmission in health-care settings since (LAIV's) licensure in 2004." To read more on this topic, see pages 35–37 in Prevention and Control of Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP) — United States, 2010–11 Influenza Season found at www.cdc.gov/mmwr/pdf/rr/rr5908.pdf.
Why is influenza vaccination important for healthcare workers? We already encourage them to stay home from work when they are sick.
Unfortunately, by the time a healthcare worker has symptoms of influenza, they will have already exposed many patients since the virus is shed for 1-2 days before symptoms begin. Do the right thing. Start planning early to make sure all employees in your work setting receive annual influenza vaccination before the influenza season begins.
I would like to help establish a policy of mandatory influenza vaccination for healthcare workers in our facility and would like to learn from others. Can you help?
You will be happy to know that more and more healthcare facilities are adopting mandatory vaccination policies for their employees. IAC has included many of these on its Honor Roll for Patient Safety, which gives special recognition to institutions that enforce mandatory vaccination for all personnel who are in the vicinity of a patient (for example, including volunteers, housekeeping staff). To read about the policies of the various facilities included in the Honor Roll, go to www.immunize.org/honor-roll/influenza-mandates/honorees.asp We hope reviewing these policies will give you the information you need to assist in developing a policy for your facility.
We have a mandatory vaccination policy in our facility; however, we allow employees to choose not to be vaccinated after filling out and signing an informed declination form. What can we do to achieve assurances that patient safety is still maintained?
Though vaccination is the most effective means of protecting your patients from influenza, there may be instances where employees are not vaccinated for medical or personal reasons. In these instances, you may want to consider reassigning unvaccinated workers to non-patient areas or requiring that they wear masks throughout the influenza season.
I heard about a hospital where more than 95% of employees received influenza vaccine last year. How did they achieve such a high level of vaccination?
There are a number of hospitals that have implemented successful programs to vaccinate their healthcare workers. One example is the Virginia Mason Medical Center in Seattle, WA that has consistently achieved high levels of vaccination among their employees and volunteers. A report covering the first five years of their program was also published in the September 2010 issue of Infection Control and Hospital Epidemiology. An abstract of the report can be found here www.ncbi.nlm.nih.gov/pubmed/20653445. IAC has developed an online Honor Roll for Patient Safety that recognizes hospitals, medical practices, professional organizations, and government entities that have taken a stand for patient safety by adopting policies endorsing mandatory influenza vaccination or by implementing mandatory influenza vaccination policies for all employees. To view the current listing of policies and position statements from leading organizations in medicine, pediatrics, pharmacy, public health, infectious diseases, and hospital administration, visit IAC's Influenza Vaccination Honor Roll at www.immunize.org/honor-roll/influenza-mandates/.
We recommend our healthcare personnel receive LAIV, but question whether NICU staff can receive this vaccine without compromising our neonates.
Neonates in an NICU are not considered severely immunocompromised. NICU personnel may receive LAIV if otherwise eligible (younger than 50 years, healthy, and not pregnant).
Does the federal law that requires providing patients with VISs apply when administering influenza vaccine to employees and volunteers in hospitals or other workplaces?
If a vaccine is covered under the National Childhood Vaccine Injury Act—and almost all vaccines routinely administered to adults are (with the exception of PPSV and zoster)–it is mandatory under federal law to give the VIS for that vaccine to the vaccinee. Therefore, when you give influenza vaccine to employees and staff, you are required by law to provide them with a VIS.
Why is it so important to vaccinate healthcare personnel against influenza?
Because HCP provide care to patients at high risk for complications of influenza, achieving high rates of vaccination among HCP will reduce disease burden and healthcare costs.
Influenza is readily transmitted for 24 hours before a person develops influenza symptoms. That means symptom-free unvaccinated HCP can transmit influenza virus to patients before developing symptoms and electing to stay home as a way to prevent transmission.
Why does CDC recommend that we consider obtaining a signed declination from healthcare personnel who refuse influenza vaccination?
Some studies have shown an increase in HCP influenza vaccine acceptance when decliners are required to sign such a statement. In addition, such statements can help a vaccination program assess the reasons for declination and plan future educational efforts. IAC has posted the following suggested declination forms for healthcare workers:
Declination of Influenza Vaccination (English) found at www.immunize.org/catg.d/p4068.pdf
  Declination of Influenza Vaccination (Spanish) found at www.immunize.org/catg.d/p4068-01.pdf
Please tell me which professional associations have endorsed mandatory influenza vaccination for healthcare workers and have created policy statements.
There are many professional associations that have issued policy statements supporting mandatory healthcare worker influenza vaccination. You can find information about these organizations as well as a list of more than 400 healthcare settings that have implemented mandatory vaccination programs on IAC's website at IAC's Influenza Vaccination Honor Roll web section at www.immunize.org/honor-roll/influenza-mandates/.
Contraindications and Precautions Back to top
For whom is influenza vaccine contraindicated?
Persons who have experienced a severe allergic reaction to a prior dose of influenza vaccine, or who are known to have a severe allergy to a vaccine component should not be vaccinated. Vaccination should be deferred for a person with moderate or severe acute illness until his/her condition improves. The use of live attenuated influenza vaccine (LAIV) is contraindicated in persons with a chronic disease that constitutes an increased risk when exposed to wild influenza virus (for example, asthma, heart and renal disease, diabetes), pregnant women, immunosuppressed persons, children younger than age 2 years, and adults older than age 49 years. A history of Guillain-Barré syndrome occurring within 6 weeks of previous influenza vaccine is a precaution for IIV and LAIV.
What is the latest ACIP guidance on influenza vaccination and egg allergy?
People who have experienced a serious systemic or anaphylactic reaction (for example, hives, swelling of the lips or tongue, acute respiratory distress, or collapse) after eating eggs should consult a specialist for appropriate evaluation to help determine if vaccine should be administered.
A previous severe allergic reaction to influenza vaccine, regardless of the component suspected to be responsible for the reaction, is a contraindication to future receipt of the vaccine.
Some people who report allergy to egg might not be egg allergic. If a person can eat lightly cooked eggs (for example, scrambled eggs), they are unlikely to have an egg allergy. However, people who can tolerate egg in baked products (for example, cake) might still have an egg allergy. If the person develops hives only after ingesting eggs, CDC recommends (1) they receive IIV (not LAIV), (2) the vaccine be administered by a healthcare provider familiar with the potential manifestations of egg allergy, and (3) the vaccine recipient be observed for at least 30 minutes after receipt of the vaccine for signs of a reaction.
An inactivated influenza vaccine that does not contain egg protein is now available in the United States. See the next question for more information about this vaccine.
For more details about giving influenza vaccine to people with a history of egg allergy, see www.cdc.gov/mmwr/pdf/rr/rr6207.pdf, pages 30-32. You may find the IAC handout "Influenza Vaccination of People with a History of Egg Allergy" helpful (see www.immunize.org/catg.d/p3094.pdf).
I heard there is an influenza vaccine that can be given to people with severe egg allergies. Is that true?
Yes. If someone age 18 years and older has a severe allergy to eggs with symptoms suggestive of anaphylaxis, then the provider can use a recombinant influenza vaccine (RIV3, Flublok, Protein Sciences) that is egg-free. Unlike current production methods for other available seasonal influenza vaccines, production of RIV3 does not use the whole influenza virus or chicken eggs in its manufacturing process. If RIV3 is not available or the person is not age-eligible, then inactivated influenza vaccine should be administered by a physician with experience in the recognition and management of severe allergic conditions.
RIV3 has a shorter shelf life than other currently available inactivated influenza vaccines. It expires 6 months from the production date. Other currently available inactivated influenza vaccines expire on June 30, 2015. Healthcare providers should check the expiration date before administering RIV3 (and all other vaccines). You can find additional information about Flublok at www.cdc.gov/flu/protect/vaccine/qa_flublok-vaccine.htm.
Is allergy to chicken or duck feathers a contraindication to receipt of an egg-based influenza vaccine?
The influenza VIS states that giving pneumococcal conjugate vaccine (PCV13) and inactivated influenza vaccine simultaneously may increase febrile seizures. Can we continue to give these two vaccines at the same time?
Yes, you can. Some, but not all studies, have reported increased rates of febrile seizures have been reported among children, especially those age 12 through 23 months, who received simultaneous vaccination with IIV and PCV13, when compared with children who received these vaccines separately. However, because of the risks associated with delaying either of these vaccines, ACIP does not recommend administering them at separate visits or deviating from the recommended vaccine schedule in any way.
Febrile seizures are not uncommon, occurring in 2% to 5% of all children; and they are generally benign. Healthcare providers should be prepared to discuss parents' questions about this issue, including questions about fever and febrile seizures.
The inactivated influenza vaccine VIS states: "Young children who get inactivated flu vaccine and pneumococcal vaccine (PCV13) at the same time may be at increased risk for seizures caused by fever. Ask your doctor for more information." ACIP chose to include this statement on the VIS to inform parents of this potential risk.
For more information, see these CDC resources: www.cdc.gov/vaccinesafety/Concerns/FebrileSeizures.html and www.cdc.gov/vaccines/pubs/hcp/vis/vis-statements/flu-tiv-pcv-note.html.
We usually instruct our patients that they should separate vaccinations and allergy shots by at least 24 hours because if there were a reaction to one or the other, it wouldn't be possible to determine which was the cause. This becomes problematic during influenza vaccination season. What should we do?
The probability of a serious allergic reaction following any vaccine is extremely low if the person is properly screened. ACIP has not issued a recommendation that desensitization injections and vaccines be separated by any specific time period; consequently, we feel that you should take the opportunity to vaccinate.
Live Attenuated Influenza Vaccine (LAIV) Issues Back to top
For whom can the intranasal influenza vaccine be used?
LAIV (FluMist) is currently approved for use only for healthy non-pregnant persons ages 2 through 49 years. Many of these persons are among the groups that are high priority for vaccination, including healthcare personnel (excluding those in close contact with severely immunosuppressed persons during periods when the immunocompromised person requires a protective environment) and other persons in close contact with high-risk groups, including household contacts of high-risk persons, contacts of children from birth through age 59 months, and contacts of adults age 50 years and older. In addition, any healthy, nonpregnant person between the ages 2 through 49 years who wants to reduce their risk of influenza or of transmitting it to others can be vaccinated with LAIV.
When available LAIV is preferred for healthy children ages 2 through 8 years unless they have: 1) a contraindication to LAIV; 2) a precaution to LAIV; 3) a history of egg allergy; 4) taken influenza antiviral medication within the previous 48 hours. ACIP states this preference because studies have shown LAIV to be more effective than inactivated influenza vaccine in preventing influenza in this age group. However, both LAIV and IIV are safe and effective in this age group. If LAIV is not immediately available, IIV should be used. Vaccination should not be delayed in order to procure LAIV.
Can LAIV be administered to persons with minor acute illnesses, such as a mild upper respiratory infection (URI) with or without fever?
Yes, however, if clinical judgment suggests nasal congestion is present that might impede delivery of the vaccine to the nasopharyngeal mucosa, deferral of administration should be considered until the congestion resolves.
Can a woman who is breastfeeding receive LAIV?
Yes. Breastfeeding is not a contraindication for routine vaccination of breastfeeding women, including LAIV.
Can LAIV be given to contacts of immunosuppressed patients?
Like other live vaccines, LAIV should not be administered to immunosuppressed persons. ACIP has stated a preference for using inactivated influenza vaccine for household members, healthcare personnel, and others who have close contact with severely immunosuppressed individuals (for example, patients with hematopoietic stem cell transplants) during those periods in which the immunosuppressed person requires care in a protective environment because of the theoretical risk that the live attenuated vaccine virus could be transmitted to the severely immunosuppressed individual and cause disease. Healthcare personnel or other persons who have close contact with persons with lesser degrees of immunosuppression (for example, persons with diabetes, persons with asthma taking corticosteroids, or persons infected with human immunodeficiency virus) who are otherwise eligible for LAIV may receive it. No special precautions need to be taken by the vaccinated person.
How long after someone is vaccinated with LAIV must they stay away from a severely immunosuppressed person (a person who is in protective [reverse] isolation)?
Persons vaccinated with LAIV should avoid contact with any person who is severely immunosuppressed for at least 7 days after receiving LAIV. There are no restrictions on being in contact with any other patients.
Is LAIV contraindicated for asthmatics?
Persons with asthma should not receive LAIV. Persons with asthma and other chronic respiratory conditions should receive inactivated influenza vaccine.
Can we give LAIV to a person who is taking an influenza antiviral medication?
An antiviral drug active against influenza virus may reduce the effectiveness of LAIV. If a person is taking an influenza antiviral drug, you should not administer LAIV until 48 hours after the person took the last dose of the influenza antiviral medication. If a person takes antiviral drugs within 2 weeks of getting the nasal-spray flu vaccine, the person should get revaccinated. However, you can give inactivated influenza vaccine (IIV) to a person who is taking an antiviral influenza drug.
Administering Vaccines Back to top
Which formulations of influenza vaccines (i.e., nasal spray, intradermal, injectable high-dose, and injectable standard-dose) are licensed for various age groups?
There are multiple manufacturers of influenza vaccine and each may have differences in their product line (for example, licensed age group, mode of administration, etc.). IAC has developed a handout that summarizes each of the products available for the coming influenza vaccination season that can be found at www.immunize.org/catg.d/p4072.pdf.
Does ACIP recommend the use of high-dose and intradermal influenza vaccines?
Yes, ACIP recommends the use of high-dose and intradermal influenza vaccines, along with all other FDA-approved inactivated influenza vaccines (IIV). ACIP has not stated a preference for any IIV product over another. The formulation or presentation a provider uses is the provider's choice as long as an age-appropriate product is used and is administered correctly. Providers need to choose the type of vaccine most appropriate for their patient population. The Immunization Action Coalition website has manufacturers' package inserts for every influenza vaccine product licensed for use in the United States that can be found at www.immunize.org/packageinserts
Does the ACIP prefer that healthcare professionals administer high-dose influenza vaccine or standard-dose influenza vaccine to people age 65 years and older?
ACIP has no preference. CDC stresses that vaccination is the first and most important step in protecting against influenza.
How is the intranasal vaccine (LAIV) administered?
The vaccine dose (0.2 mL) comes inside a special sprayer device. A plastic clip on the plunger divides the dose into two equal parts. The patient is seated in an upright position with head tilted back. Half of the contents of the sprayer (0.1 mL) is sprayed into each nostril.
The pneumococcal conjugate vaccine (PCV13) package insert says that in adults, antibody responses to Prevnar 13 (Pfizer) were diminished when given with inactivated influenza vaccine. Does this mean we should not give PCV13 and influenza vaccine at the same visit?
No. The available data have been interpreted that any changes in antibody response to either vaccines' components were clinically insignificant. If PCV13 and influenza vaccine are both indicated and recommended they should be administered at the same visit. See the PCV13 ACIP recommendations, www.cdc.gov/mmwr/pdf/wk/mm6337.pdf, page 824.
What is the preferred anatomic site for administration of inactivated influenza vaccine (IIV)?
IIV should be administered in the anterolateral thigh muscle of an infant or young child and in the deltoid muscle of an older child, adolescent or adult. The anterolateral thigh muscle can also be used for an older child, adolescent or adult if necessary.
Some of our patients believe that they have had reactions to influenza vaccine in the past, and request the dose to be split into 2 doses administered on different days. Is this an acceptable practice?
This is definitely not an acceptable practice. Doses of influenza vaccine (or any other vaccine) should never be split into “half doses”. If a “half dose” is given it should not be accepted as a valid dose and should be repeated as soon as possible with a full age-appropriate dose.
Should staff at drive-through influenza vaccination clinics encourage drivers to park and wait for 15 minutes after vaccination to make sure they don't have a vaccination reaction or syncopal (fainting) episode?
Yes. Syncope has been reported following vaccination. It is prudent for all persons to be observed for syncope for at least 15 minutes after vaccination.
Is it okay to draw up vaccine into syringes at the beginning of the day? If it isn't, how much in advance can this be done?
CDC discourages the practice of prefilling vaccine into syringes for several reasons, including
the increased possibility of administration and dosing errors,
  the increased risk of inappropriate storage,
  the probability of bacterial contamination since the syringe will not contain a bacteriostatic agent, and
the probability of reducing the vaccine's potency over time because of its interaction with the plastic syringe components.
Prefilling vaccine into syringes also violates basic medication administration guidelines, which state that an individual should administer only those medications he or she has prepared and drawn up.
Although pre-drawing vaccine is discouraged, a limited amount of vaccine may be pre-drawn in a mass-immunization clinic setting under the following conditions:
only a single type of vaccine (for example, influenza) is administered at the mass-immunization clinic setting,
  vaccine is not drawn up in advance of its arrival at the mass-vaccination clinic site,
  these pre-drawn syringes are stored at temperatures appropriate for the vaccine they hold,
no more than 1 vial or 10 doses (whichever is greater) is drawn into syringes, and
  clinic staff monitor patient flow carefully and avoid drawing up unnecessary doses or delaying administration of pre-drawn doses.
At the end of the clinic day, any remaining vaccine in syringes prefilled by staff should be discarded.
Sometimes I am unable to get 10 doses of influenza vaccine out of a 5.0 mL (10-dose) vial. Do you have any suggestions?
Certain vaccine syringes have small hubs where a volume of the vaccine that is withdrawn from the vial collects and is not available to be injected. Syringes without a hub are available; their use results in less vaccine wastage.
We inadvertently administered a 0.5 mL dose of FluLaval (GSK) to a 2-year-old child before realizing that the vaccine is only licensed for use in people age 3 years and older. Do we need to repeat the dose with an age-appropriate product?
No, the dose does not need to be repeated. However, two errors actually occurred here. In addition to the age discrepancy, the child also received a 0.5 mL dose of vaccine rather than the correct dose (0.25 mL) for the child’s age. Clinicians should carefully select an influenza vaccine that is licensed for the age group of the person being vaccinated. Fluzone 0.25 mL (sanofi) is the only inactivated influenza vaccine approved for use in children age 6 months through two years. The live attenuated nasal spray vaccine (LAIV, FluMist, MedImmune) is approved for use in most healthy children age 2 years and older (as well as for healthy nonpregnant adults through age 49 years).
If the child should need a second dose of influenza vaccine, an age-appropriate vaccine should be selected. The Immunization Action Coalition’s educational piece “Influenza Vaccine Products for the 2013–2014 Influenza Season” (available at www.immunize.org/catg.d/p4072.pdf) provides helpful information on the wide variety of influenza vaccines in use this season.
We inadvertently administered intradermal influenza vaccine (Fluzone ID, sanofi) to a patient who is not in the recommended age range of 18 through 64 years. What should we do now?
Because people younger than age 9 years or older than 65 years are more likely to have skin that is too thin for proper intradermal administration, a dose given to a person in these age ranges should be considered invalid, and the patient should be revaccinated. For people age 9 through 17 years, the dose is considered valid and does not have to be repeated if the clinician is certain that the dose was administered intradermally rather than subcutaneously. If there is any doubt about whether the dose was injected intradermally, it should be repeated.
Storage and Handling Back to top
How should LAIV and IIV be stored?
Both the inactivated influenza vaccine (IIV) and the live attenuated influenza vaccine (LAIV) should be refrigerated at temperatures between 35°F (2°C) and 46°F (8°C).
This page was reviewed on February 25, 2015
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