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Issue Number 297            February 20, 2002


  1. CDC posts online Summary of Major Changes in the "General Recommendations on Immunization"


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February 20, 2002

The Centers for Disease Control and Prevention (CDC) has issued an online summary of the seven major changes made by the Advisory Committee on Immunization Practices (ACIP) in the new "General Recommendations on Immunization," which were published on February 8, 2002 (see IAC EXPRESS #295). The General Recommendations were last published in 1994.

This summary will help immunizers navigate the new recommendations by highlighting the most significant additions and revisions.

The seven major changes summarized are as follows:

-No Vaccination Schedules
-4-Day "Grace Period" for Timing and Spacing of Vaccines
-Guidance for Non-Simultaneous Administration of Live Vaccines
-Guidance for Non-Standard Route or Site of Administration
-Vaccination of Internationally Adopted Children
-Aspiration Before Injection
-Management of Preterm Infants Whose Mothers' HBsAg Status Is Unknown

Here is the full text of the Summary of Major Changes:



Unlike previous versions of the General Recommendations, this revision does not include vaccination schedules. Beginning in 1995, the Recommended Childhood Immunization Schedule has been published annually by the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP). The 2002 schedule is available on the National Immunization Program website at


Since 1994, ACIP has recommended that doses of vaccine separated by less than the recommended minimum interval should not be considered part of a primary series. ACIP continues to recommend  that vaccine doses should not be given at intervals less than the minimum intervals or earlier than the minimum age. An extensive listing of recommended and minimum intervals and ages for vaccination is included in the document. In an effort to increase the flexibility of the complicated childhood immunization schedule, ACIP now recommends that vaccine doses administered up to four days before the minimum interval or age can be counted as valid. ACIP believes that administering a dose a few days earlier than the minimum interval or age is unlikely to have a significant negative effect on the immune response to that dose.

This 4-day "grace period" should NOT be used when scheduling future vaccination visits. It should be used primarily when reviewing vaccination records. The 4-day "grace period" may also be useful in  situations where a child visits a provider a few days earlier than a scheduled vaccination appointment. For example, if a child comes to the office or clinic for an ear check 27 days after his or her second DTaP dose, the provider could administer the third DTaP at that visit rather than having the child return for vaccination the next day.


Since 1983, ACIP has recommended that whenever possible, live-virus vaccines not administered on the same day should be administered at least 30 days apart, because of concern that the vaccine given first could interfere with response to the vaccine given second. These concerns were based on two 1965 studies that indicated that recent measles vaccination reduced the response to smallpox vaccine. A study recently published in Morbidity and Mortality Weekly Report (MMWR 2001;50:1058-61) found that children who received varicella vaccine less than 30 days after MMR vaccination had a 2.5-fold increased risk of breakthrough varicella (i.e., varicella disease in a vaccinated person) compared with those who received varicella vaccine before, simultaneous with, or more than 30 days after MMR.

Until now, ACIP has not provided guidance on the course of action if two live-virus vaccines were given less than 30 days apart. In the revised General Recommendations, ACIP recommends that if two live  parenteral vaccines are given less than 28 days apart, the vaccine given second should not be counted  as valid and should be repeated at least 4 weeks later. One exception to this recommendation is that yellow fever vaccine may be given at any time after measles vaccine.


In the 1994 revision of the General Recommendations, ACIP recommended that any vaccination using less than a standard dose or a nonstandard route or site of administration should not be counted, and the person should be revaccinated according to age. This recommendation was intended to discourage inappropriate vaccination practices, such as administration of half doses (a practice mostly associated with whole cell DTP vaccine), or inappropriate routes of vaccination (particularly the gluteus). This recommendation also led to repetition of some vaccine doses given by routes other than those recommended by the manufacturer, but whose route of administration probably had no significant effect on immunogenicity (for example, administration of MMR by the intramuscular route rather than the recommended subcutaneous route). In the revised General Recommendations, ACIP continues to strongly discourage variation from the recommended route, site, or dose of any vaccine. However, ACIP now recommends repeating doses only in cases where a reduction in immunogenicity has been demonstrated: rabies and hepatitis B vaccines administered in the gluteus, and hepatitis B vaccine administered by any route other than intramuscular injection (i.e., intradermal or subcutaneous injection).


Since 1994, ACIP has recommended that vaccines administered outside the United States could be accepted as valid if they were documented by a written, dated record. There is conflicting information  regarding the accuracy of vaccination records for internationally adopted children, particularly those adopted from orphanages in China, Russia, and other eastern European countries, and it is difficult to determine if a child is protected on the basis of their country of origin and their records alone. ACIP continues to recommend that vaccines received outside the United States can usually be accepted if there is written, dated documentation and the age, spacing and timing is comparable with that recommended in the United States. But it is especially important for the provider to carefully review the records of children adopted from orphanages, due to potential issues of authenticity. If there is any doubt about the validity of a vaccination record (for instance, doses dated before the child's birth or a record of receiving MMR or Hib vaccine, which are not commonly used in less developed countries), age-appropriate revaccination is generally recommended. Serologic testing may be considered if the parent or provider does not wish to repeat all doses, particularly for DTaP if three or more doses are documented. The General Recommendations provides guidance on selection and interpretation of these serologic tests.


Previous versions of the General Recommendations have recommended aspiration (i.e., gently pulling back on the plunger to check for blood before injection) prior to injection, particularly before intramuscular injection. No data exist to document the necessity of this procedure. The 2002 General Recommendations on Immunization does not recommend aspiration before injection.


Neither the current ACIP statement nor the 2002 schedule addresses hepatitis B post-exposure management of preterm (<2 kg) infants whose mothers' HBsAg status is unknown.

The revised General Recommendations recommends that preterm infants whose mothers are HBsAg positive OR whose HBsAg status is unknown should be given both hepatitis B vaccine and HBIG within 12 hours of birth. For all preterm infants, the birth dose of hepatitis B vaccine should not be counted, and the infant should receive 3 additional doses at 1, 2, and 6 months of age.


To see this Summary of Major Changes on CDC's website, go to:

The Immunization Action Coalition (IAC) strongly recommends that all health care settings with vaccination services keep a hard copy of the General Recommendations with their other essential immunization reference materials and that clinic staff be encouraged to read them.

Links to the 2002 General Recommendations on Immunization are below. Note that the document is fairly large (6418 KB) and, depending on your computer system, may take a while to download. If you would prefer to order a hard copy of the Recommendations from CDC, you can do so by either calling the National Immunization Hotline at (800) 232-2522 or using CDC's online publications order form at

To obtain the 2002 General Recommendations on Immunization from CDC's website, go to:

To download a camera-ready (PDF-format) copy of the 2002 General Recommendations on Immunization, go to:

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