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Vaccine Safety

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Vaccine Safety
Note: Information about the safety for specific vaccines are included in the Ask The Expert set for that vaccine.
Some parents are requesting that we space out their infant's vaccinations because they are concerned that receiving multiple vaccinations at a single office visit might overwhelm the infant's immune system. What do you think about using alternative schedules?
Vaccine recommendations are determined after extensive studies in large clinical trials. They include studies on how vaccine recipients respond to multiple vaccines given simultaneously. The overall aim is to provide early protection for infants and children against vaccine-preventable diseases that could endanger their health and life. No scientific evidence exists to support that delaying vaccinations or separating them into individual antigens is beneficial for children. Rather, this practice prolongs susceptibility to disease, which could result in a greater likelihood of the child becoming sick with a serious or life-threatening disease. There could also be added expense (e.g., multiple office visits), additional time off from work for parents, and increased likelihood that the child will fail to get all necessary vaccinations.
Many of my patients are reading The Vaccine Book, in which the author, Dr. Bob Sears, cites studies that he interprets as showing that the amount of aluminum found in certain vaccines might be unsafe. He thinks it is better to separate aluminum-containing vaccines, rather than give them according to the recommended U.S. immunization schedule. I would love any information you have about this.
Paul Offit, MD, and Charlotte Moser, BS, of the Vaccine Education Center (VEC) at the Children's Hospital of Philadelphia, published an article, "The Problem with Dr. Bob's Alternative Vaccine Schedule," in the January 2009 issue of Pediatrics. It includes a section about aluminum. You can read it in its entirety at pediatrics.aappublications.org/cgi/content/full/123/1/e164.
Here are some additional sources of related information:
"Aluminum in Vaccines: What you should know" is available from VEC at www.chop.edu/export/download/pdfs/articles/vaccine-education-center/aluminum.pdf.
"Vaccine Ingredients: What you should know" is available from VEC at www.chop.edu/export/download/pdfs/articles/vaccine-education-center/vaccine-ingredients.pdf.
Does the thimerosal in some vaccines pose a risk?
Thimerosal, a very effective preservative, has been used to prevent bacterial contamination in vaccine vials for more than 50 years. It contains a type of mercury known as ethylmercury, which is different from the type of mercury found in fish and seafood (methylmercury). At very high levels, methylmercury can be toxic to people, especially to the neurological development of infants.
In recent years, several large scientific studies have determined that thimerosal in vaccines does not lead to neurologic problems, such as autism. Nonetheless, because we generally try to reduce people's exposure to mercury if at all possible, vaccine manufacturers have voluntarily changed their production methods to produce vaccines that are now free of thimerosal or have only trace amounts. They have done this because it is possible to do, not because there was any evidence that the thimerosal was harmful.
I understand that certain vaccines contain aluminum and/or formaldehyde. Could you provide me with the research showing the "safe" amounts of aluminum and formaldehyde that can be injected per pound of body weight?
The production of a few vaccines, including those for varicella, rubella, and hepatitis A, involves growing the viruses in human cell culture. Two human cell lines provide the cell cultures needed for producing vaccines; these lines were developed from two legally aborted fetuses in the 1960s. These cell lines are maintained to have an indefinite life span. No fetal tissue has been added since the cell lines were originally created.
The FDA performed two studies directly related to your question which demonstrate the amounts injected with vaccines are well below what are considered toxic levels. The following citation is about aluminum in vaccines: www.fda.gov/BiologicsBloodVaccines/ScienceResearch/ucm284520.htm.
Regarding formaldehyde, the FDA did the following study, and estimated that less formaldehyde is received from vaccines by infants than infants produce themselves: www.accessdata.fda.gov/scripts/publications/search_result_record.cfm?id=45918.
Information on vaccine additives is available on the CDC website at www.cdc.gov/vaccines/vac-gen/additives.htm and on the FDA website at www.fda.gov/biologicsbloodvaccines/safetyavailability/vaccinesafety/ucm187810.htm.
A patient has expressed concern that some vaccines have been produced in fetal tissue. How can I address this concern?
The production of a few vaccines, including those for varicella, rubella, and hepatitis A, involves growing the viruses in human cell culture. Two human cell lines provide the cell cultures needed for producing vaccines; these lines were developed from two legally aborted fetuses in the 1960s. These cell lines are maintained to have an indefinite life span. No fetal tissue has been added since the cell lines were originally created.
Some parents are concerned about this issue because of misinformation they have encountered on the Internet. Two such untrue statements are that ongoing abortions are needed to manufacture vaccines and vaccines are contaminated with fetal tissue.
Parents can read the facts and several thought-provoking articles about this issue at www.immunize.org/concerns/religious.asp and then make an informed decision
A Catholic bishop's statement that Catholic parents have no general obligation to refuse permission for these vaccines is summarized at www.cdc.gov/vaccines/imz-managers/laws/rubella-cathnews.html.
Where can I find more information to help address my patients' concerns about vaccine safety?
There are many excellent websites that have information about vaccine safety, including the American Academy of Pediatrics, the CDC, Every Child by Two, the Immunization Action Coalition, the National Network for Immunization Information, the Institute of Medicine, and the Vaccine Education Center, Children's Hospital of Philadelphia.
What is syncope?
Syncope, also called fainting, is a temporary loss of consciousness as a result of decreased blood flow to the brain. The most common form of fainting is called “vasovagal” fainting. This type of fainting can be triggered by an event associated with pain or anxiety. Some people may experience jerking movements after fainting which are not seizures. Published literature reveals that about 3% of men and 3.5% of women report at least one episode of fainting during their lifetime.
Who is more likely to experience fainting after immunization?
Reports from the Vaccine Adverse Event Reporting System (VAERS-see questions below) show that fainting is more common among adolescents. From January 1, 2005--July 31, 2007, 62% of the fainting reports to VAERS were among adolescents, 11 to 18 years old. Although this is a relatively high percentage, we cannot use VAERS data (due to the limitation of VAERS) to determine how frequently fainting occurs after vaccination.)
Do specific vaccines cause fainting?
Nearly all vaccines have been reported to be associated with the fainting. Post-vaccination fainting has been most frequently reported after three vaccines commonly given to adolescents (HPV, MCV4, and Tdap). However, we do not know whether the vaccines are responsible for post-vaccination fainting or if the association with these vaccines simply reflects the fact that adolescents are generally more likely to experience fainting.
Can fainting and related injury after immunization be prevented?
Falls that occur due to fainting after vaccination can be prevented by assuring that the vaccinated person is sitting in a chair or lying down and is observed for 15 minutes following vaccination.
Is there any harm in giving an extra dose of MMR to a child of age seven years whose record is lost and the mother is not sure about the last dose of MMR?
In general, although it is not ideal, receiving extra doses of vaccine poses no medical problem. Receiving excessive doses of tetanus toxoid (e.g., DTP, DTaP, DT, Tdap, or Td) can increase the risk of a local adverse reaction, however. For details, consult the ACIP's General Recommendations on Immunization at www.cdc.gov/mmwr/pdf/rr/rr6002.pdf, page 8.
Vaccination providers frequently encounter people who do not have adequate documentation of vaccinations. Providers should only accept written, dated records as evidence of vaccination. With the exception of influenza vaccine and pneumococcal polysaccharide vaccine, self-reported doses of vaccine without written documentation should not be accepted. An attempt to locate missing records should be made whenever possible by contacting previous healthcare providers, reviewing state or local immunization information systems, and searching for a personally held record.
If records cannot be located or will definitely not be available anywhere because of the patient's circumstances, children without adequate documentation should be considered susceptible and should receive age-appropriate vaccination. Serologic testing for immunity is an alternative to vaccination for certain antigens (e.g., measles, rubella, hepatitis A, diphtheria, and tetanus).
What is the Vaccine Adverse Event Reporting System (VAERS)?
As the name implies, VAERS is a nationwide system for monitoring adverse events following vaccination. VAERS is operated jointly by the FDA and the CDC since 1990.
How do I report an adverse event to VAERS?
Reports can be submitted online through the VAERS website (vaers.hhs.gov/esub/step1) or on a paper VAERS report form. You may use photocopies of the form to submit reports.
A postage-paid VAERS report form can be downloaded from the VAERS website at vaers.hhs.gov/esub/index. Completed paper VAERS forms may be returned by fax to (877) 721-0366 or by mail to VAERS, PO Box 1100, Rockville, MD 20849-1100.
If a patient faints following vaccination, should we submit a report to VAERS?
Yes. Any occurrence of medical significance warrants a VAERS report. VAERS looks for trends, so such information is helpful. You can obtain more information about VAERS at vaers.hhs.gov or by calling (800) 822-7967.
How do I decide whether to report an adverse event to VAERS?
All significant health events that may have been related to a dose of vaccine, particularly those that lead to hospitalization, disability, or death, should be reported to VAERS. The healthcare provider doesn't need to be certain the event was vaccine related in order to report it. It is not necessary to report minor adverse reactions, such as local reactions or low-grade fever.
Why are zoster, pneumococcal polysaccharide (PPSV23) and meningococcal serogroup B (MenB) vaccines not covered by the National Vaccine Injury Compensation Program?
The National Vaccine Injury Compensation Program includes payment only for injuries determined to have occurred following vaccination with a vaccine routinely recommended for children in the United States. The recipient can be of any age, but the vaccine must be routinely recommended for children and teens through age 18 years. Zoster, PPSV23 and MenB vaccines are not routinely recommended for children. Zoster is only licensed and recommended for adults. PPSV23 and MenB vaccines are routinely recommended only for select high-risk groups of children and adults. More information about the program and the covered vaccines is at www.hrsa.gov/vaccinecompensation/coveredvaccines/index.html.
This page was updated on January 7, 2017.
This page was reviewed on December 14, 2016.
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