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Questions and Answers
NIP Answers Your Questions
General Vaccination Topics
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General Questions

  • How are vaccines attenuated and inactivated?

    Attenuation (weakening) is usually accomplished through serial passage of the organism through various tissue culture media. Inactivation (killing) is done with formalin and/or heat. "Understanding Vaccines" (NIAID) (2/13/03)

  • Do infants get passive immunity if the mother is immunized or if the mother has the virus?

    The infant will receive whatever antibodies the mother has, whether they were acquired from infection or vaccination. (2/13/03)

  • Passive immunity interferes with live vaccines. Therefore, if mothers are still nursing their infants at one year of age, do live virus vaccines for the infants need to be delayed? If so, how long after mom stops nursing do we wait?

    There is no reason to delay vaccination because of breastfeeding. Breastfeeding is a good thing and it is not a contraindication to administratin of any vaccine except smallpox. ACIP General Recommendations (see page 18) (2/13/03) More Information

  • Can ibuprofen be used safely following a live vaccine (in children) instead of acetaminophen? We have some patients who are allergic to acetaminophen.

    Acetaminophen or ibuprofen can be used following vaccination unless medically contraindicated for that patient. ACIP General Recommendations (see page 13) and "After the Shots" (IAC) (2/13/03)

  • When a child has an anaphylactic reaction after multiple simultaneous injections, how do we know which vaccine the child is allergic to?

    In this situation we would recommend an allergy consult prior to administering another dose of any vaccine administered at the time of the anaphylactic reaction. (2/13/03)

  • How do I find out about vaccine components in case my patient reports an allergy?

    There are several resources: The manufacturer’s product information (package insert) that accompanies the vaccine, The “Vaccine Excipient and Media Summary” table in Appendix A of Epidemiology and Prevention of Vaccine-Preventable Diseases (the Pink Book), and in the book ImmunoFacts, (6/26/03)

  • Please address the latex component in vaccine stoppers in relation to patients with latex allergies.

    If a person reports a severe (anaphylactic) allergy to latex, vaccines supplied in vials or syringes that contain natural rubber should not be administered, unless the benefit of vaccination outweighs the risk of an allergic reaction to the vaccine. For latex allergies other than anaphylactic allergies (e.g., a history of contact allergy to latex gloves), vaccines supplied in vials or syringes that contain dry natural rubber or natural rubber latex can be administered. ACIP General Recommendations (see page 17) (2/13/03)
    More Information

  • What is the danger of over-immunizing in cases where you can’t find the immunization records? Is it O.K. to revaccinate?

    Every reasonable effort should be made to locate a patient’s immunization record. However, if it cannot be located, then the recommendation is to revaccinate according to their current age. The concern is the risk of localized reaction with the more immunogenic vaccines like tetanus- and diphtheria-containing vaccines. In some situations you may want to do serologic testing for antibody. There is a good discussion and helpful table in the General Recommendations about which vaccines should be repeated and when you may want to consider testing. ACIP General Recommendations (see pages 8, 20-21). (2/13/03)

  • If someone has suffered a major blood loss, should they be revaccinated after they recover?

    No, this is not necessary. Your immunologic memory resides primarily in your bone marrow. The only situation where a person should be re-immunized is if their bone marrow is ablated by drugs or radiation as with a bone marrow transplant. (2/13/03)

  • Should a nurse who is receiving chemotherapy be administering live vaccines?

    It really should not be a problem. The vaccines are in a sealed vial, are drawn into a syringe, and then injected under the skin. Also, the health-care provider administering the vaccines should be immune to measles, mumps, rubella and varicella. It should not be a problem with yellow fever vaccine either. Smallpox vaccine, however, is an exception. Anyone who has not been recently vaccinated against smallpox should not be administering the vaccine. The vaccine is in an open vial and is administered as a drop on the bifurcated needle so there is risk of exposure to the vaccine. (2/13/03)

  • If a patient is on antibiotics (e.g., tetracycline for acne) for chronic problem , would this have any effect on any live vaccine?

    No. Antibiotics do not have an effect on the immune response to a vaccine. No commonly used antibiotic or antiviral will inactivate a live virus vaccine. (6/26/03)



  • Two live virus vaccines, if not given on the same day, must be separated by at least 28 days. If a second live vaccine is inadvertently given before 28 days, how long should we wait to give the repeat dose?

    If injected live vaccines not given simultaneously are separated by less than 4 weeks, the vaccine administered second should not be counted as a valid dose and should be repeated. The repeat dose should be administered at least 4 weeks after the last (invalid) dose. (2/20/03)
    More Information

  • Does the four day grace period include the minimal interval between live vaccine immunizations?

    The 4-day grace period can be applied to any value in Table 1 of the ACIP General Recommendations. Therefore it can be applied to the interval between two doses of the same live vaccine (e.g., MMR doses 1 & 2 or varicella doses 1 & 2). However, it does not apply to the interval between the doses of two different live vaccines (e.g., MMR & varicella), which should be separated by 28 days. ACIP General Recommendations (see pages 4-5) (2/13/03)
    More Information

  • Does the 4-day grace period apply to the accelerated schedule when giving a vaccine series?

    Any accelerated or catch-up schedule should not include doses administered at ages or intervals less than those recommended in Table 1 of the ACIP General Recommendations. The 4-day grace period should not be considered when scheduling doses of vaccine. But if a dose of vaccine is inadvertently administered 4 days earlier than the appropriate age or interval on Table 1, it needn't be repeated. ACIP General Recommendations (see page 3) (2/13/03)

  • Why can't inactivated vaccines be given to infants under 6 weeks old?

    Mainly because there are few safety or efficacy data on doses given before 6 weeks of age, and the vaccines aren’t licensed for this use. What data exist suggest that the response to doses given before 6 weeks is poor, except for hepatitis B vaccine. ACIP General Recommendations (see page 2) (2/13/03)

  • If an expired dose of live vaccine is given, when should it be repeated?

    ACIP does not specifically address the timing for repeating doses of expired vaccine. However, it would be prudent to wait 4 weeks (at least one incubation period) before repeating a dose of live vaccine that has expired. Even though the vaccine is expired, it might retain some viability that could interfere with the repeat dose. Therefore, it is best to wait 4 weeks to be sure. However, if an expired inactivated vaccine is inadvertently given, we do not know of a biologic reason why the dose could not be repeated immediately, although there is still no official recommendation. (4/16/04)

    More Information

  • If a child has RSV disease, how soon can DTaP, IPV, or other vaccines be given? The child is not taking any medications.

    Any moderate or severe acute illness with or without fever is a temporary contraindication to the administration of any vaccine. The child can be vaccinated when symptoms abate. ACIP General Recommendations (see page 11) (2/13/03)
  • We have a baby that came to our clinic this morning who gets RSV shots because she was premature and the mom was wondering if it was okay for her to receive PCV7 and Hib vaccines. She thought they were all given to treat the same thing. What do you recommend?

    PCV7 and Hib vaccines are inactivated vaccines so there is no concern about interference from immune globulins. In fact, if the child is receiving Synagis, then you could even give live vaccines if they are indicated, because Synagis is monoclonal (it contains only antibodies to RSV) so it will not interfere with vaccine antigens. You may want to educate the mother about what the vaccines and RSV protect against and explain to the mother that the RSV provides temporary immunity against RSV only, and is not a vaccine. ACIP General Recommendations (see page 7) (2/13/03)

  • When we speak of "simultaneous administration" of vaccines, what does “simultaneous” mean? Does it mean the same day, hour, or what?

    Simultaneous means the same day -- the same clinic day. If someone receives a vaccine in the morning and then another that same afternoon, this would be considered simultaneous. (2/13/03)

  • What are the recommendations regarding spacing of vaccines and PPD testing?

    All vaccines may be given on the same day as a TB skin test, or any time after a TB skin test is applied. However, if MMR has been given, and one or more days have elapsed, we recommend waiting 4-6 weeks before giving a routine TB skin test. No information on the effect of varicella or other live injected vaccines on a TB skin test is available. Until such information is available, it is prudent to apply rules for spacing measles vaccine and TB skin testing to these vaccines. There is no evidence that inactivated vaccines interfere with PPD response. ACIP General Recommendations (see page 16) (2/13/03) More Information
  • Can a PPD be administered to a patient has had BCG vaccine?

    Yes. As we understand the current recommendation, you should interpret the PPD result without consideration for the person’s BCG status. Even if they have a history of BCG vaccination, if there is a strong positive PPD reading you should interpret it as infection with Mycobacterium tuberculois. (2/13/03) More Information

  • A person received 5 doses of pentevalent vaccine in Mexico. If the spacing is right can we consider this a complete series and are any boosters needed?

    There are at least two different pentevalent vaccines available. But the bottom line is that any vaccines received outside the United States are considered valid doses if the ages and intervals between doses are consistent with Table 1 in the General Recommendations. This is true even if it is a combination vaccine that does not exist in the U.S., like DTaP-Hib.

    Even if the child has received 5 doses of DTaP, we would recommend an additional dose at school entry if the last dose was given before the 4th birthday. You may want to give that dose at 5 or 6 years of age to reduce the chance of a local reaction. ACIP General Recommendations (see pages 19-21) (2/13/03)



  • In the General Recommendations it states that if you give a subcutaneous (SQ) vaccine by the intramuscular (IM) route, you do not have to repeat the dose. What if you give an IM vaccine by the subcutaneous route?

    This recommendation was revised in the 2002 General Recommendations. Hepatitis B and rabies vaccines not given by the IM route should be repeated. The Division of Viral Hepatitis also recommends that Hepatitis A vaccine should be repeated if it is not given by the IM route. Otherwise, IM vaccines needn't be repeated if inadvertently given SQ. However, remember for optimal immune response, the vaccine should be administered by the recommended route. If someone is routinely administering a vaccine(s) by a route that is not recommended, then some education is needed. ACIP General Recommendations (see pages 13-14). (2/13/03)

  • As the number of injections given at one encounter increases, we are running out of injection sites. If we defer an immunization for this reason, how long before we can re-use an injection site?

    We strongly recommend that you do not defer any recommended vaccines. This is a missed opportunity. No upper limit has been established regarding the number of vaccines that can be administered in one visit. ACIP and AAP consistently recommend administration of all indicated vaccines. There is no indication, or reason to believe, that this practice is harmful to the child.

    You can administer 2 intramuscular (IM) injections in each leg. They should be separated by 1”-2” to avoid overlap of any local reactions. You may want to put DTaP in one leg and PCV7 in the other leg, since they may be more reactive. IPV, MMR, and varicella can all be administered subcutaneously (SQ) in the posterior fatty triceps area of the arm or the upper fatty area of the thigh. ACIP General Recommendations (see page 12), Vaccine Administration guidelines, Immunization Techniques video (2/13/03)

  • What do you recommend if a person receives Hepatitis B or rabies vaccine in the gluteal area?

    The immunogenicity of hepatitis B vaccine and rabies vaccine is substantially lower when the gluteal rather than the deltoid site is used for administration. Doses of rabies vaccine administered in the gluteal site should not be counted as valid doses and should be repeated. Hepatitis B vaccine administered by any route or site other than intramuscularly in the anterolateral thigh or deltoid muscle should not be counted as valid and should be repeated, unless serologic testing indicates that an adequate response has been achieved. ACIP General Recommendations (see pages 13-14) (2/13/03)

  • A nurse was administering the first dose of DTaP vaccine to a 2 month old child. Some of the vaccine leaked out of the needle. Should we revaccinate?

    When this happens, it is difficult to judge how much vaccine the child received. This would be a nonstandard dose and should not be counted. You should go ahead and reimmunize the child at that time. ACIP General Recommendations (see page 14) (2/20/03)



  • Is there a vaccine information sheet for immune globulin?

    There are no Vaccine Information Statements (VIS) are available for immune globulins. A VIS for immune globulin use may be developed in the future. (2/13/03)

  • Are states required by law to have an immunization registry?

    No. However, most, if not all, states are at some stage of registry development. Use of immunization registries is strongly recommended, and the National Immunization Program is working closely with states and territories to facilitate their development and use. NIP Registry Website (2/13/03)

  • Is there any mechanism in place to screen the immunization records of high school foreign exchange students before they arrive at their assigned schools in the U.S.? By the time they arrive in this country and report for school it can be quite difficult to get them to obtain required vaccines. It seems it would be much more effective to make required vaccines for US school children mandatory for foreign exchange students before they arrive in this country.

    Proof of vaccination requirements apply to aliens who seek an immigrant visa or adjustment of status for permanent residence, but not for temporary admission to this country. Also, school entry requirements are mandated by individual states, not the federal government. It would seem prudent for the state immunization program and schools to communicate with the folks managing the foreign exchange student programs and families who will be sending and sponsoring these students about the immunization requirements. Technical Instructions for Civil Surgeons (2/20/03)

  • If an individual does not have an immunization record, what should we do?

    Vaccination providers frequently encounter persons who do not have adequate documentation of vaccinations. Providers should only accept written, dated records as evidence of vaccination. With the exception of pneumococcal polysaccharide vaccine, self-reported doses of vaccine without written documentation should not be accepted.

    Although vaccinations should not be postponed if records cannot be found, an attempt to locate missing records should be made by contacting previous health-care providers and searching for a personally held record. If records cannot be located, these persons should be considered susceptible and should be started on the age-appropriate vaccination schedule. Serologic testing for immunity is an alternative to vaccination for certain antigens (e.g., measles, mumps, rubella, varicella, tetanus, diphtheria, hepatitis A, hepatitis B, and poliovirus). ACIP General Recommendations (see pages 8, 19-21) (2/20/03)

  • If someone is traveling to another country, how do we know what vaccines are needed, especially if they have no immunization records? Should we draw blood to see if they are already immune?

    Vaccines recommended for travel to specific areas can be found on CDC's Travelers Health website. If there is no record of immunizations, then we recommend that you vaccinate.

    S erologic testing for immunity is an alternative to vaccination for certain antigens (e.g., measles, mumps, rubella, varicella, tetanus, diphtheria, hepatitis A, hepatitis B, and poliovirus). ACIP General Recommendations (see pages 8, 19-21) (2/20/03)

  • Are immunizations public information? Should a nurse give a child’s vaccine record to the day care where the child is registered and vaccinations are a prerequisite for admission?

    The best course of action would be to provide the record to the parent or legal guardian who can then give the record to the day care or school. We would recommend that you consult your state immunization program for guidance.

    You will find information on HIPPA in the Immunization Update 2003 broadcast script, at Additional HIPAA information is available at, (8/21/03)

  • (For HIPAA purposes) Are immunization records public record?

    I don’t believe immunizations are a public record. Immunization records are part of the individual’s medical record. You will find further guidance about HIPAA uidelines and sharing immunization information at, (8/21/03)

  • When patients are receiving vaccines, is it necessary for the patient/parent to sign each time a vaccine in a series is administered or is the first in a series adequate? Also, are the signatures really necessary? Would documentation in the record that the Vaccine Information Statement (VIS) was given and parent gave consent (without actually having the signature) suffice? Are there any reference documents that address this topic?

    There is no federal requirement for signed consent to vaccinate. Please consult your state immunization program and agency regarding signed consent. The following website provides federal guidelines regarding documentation of immunizations in the medical record, (8/21/03)


Vaccine Storage and Handling

  • When a multi-dose vial is opened and a dose has been used, how long can that vial be retained for use?

    We recommend that you ALWAYS review the storage and handling guidelines in the manufacturer’s package insert that accompanies the vaccine. However, in almost all cases, multi-dose vaccine vials can be used until the expiration date on the vial as long as the vaccine does not take on an unusual appearance and the vial is stored according to manufacturer guidelines.

    One exception is Menomume. Unused vaccine from a multi-dose vial of Menomune should be refrigerated at 2°- 8° C (35°- 46° F) and discarded 35 days after reconstitution if not used. [NOTE: Was formerly 10 days after reconstitution.] (2/20/03)

  • How long can any inactivated vaccine remain refrigerated while in the syringe?

    NIP strongly discourages prefilling syringes. Commercial syringes are not designed for vaccine storage. At the end of the clinic day, any remaining vaccine in syringes (other than manufacturers' prefilled syringes) should be discarded. Vaccine that has been drawn up and not administered may not be used on subsequent days. Additional information is available in the Vaccine Storage and Handling Toolkit (, Chapter 11, pages 6-8. (10/18/05)


Additional Information

Breastfeeding and Passive Immunity

The antibody in breast milk is secretory IgA antibody. What is needed to protect against vaccine-preventable diseases is IgG antibody in the blood. IgA antibody is basically absorbed like protein, not like antibody. There is some evidence that breastfeeding will reduce the risk of Hib disease and maybe pneumococcal disease. There is also some evidence that breastfeeding actually improves the immunogenicity of some inactivated vaccines.

Pre-exposure smallpox vaccination is contraindicated for women who are breastfeeding because of the skin-to-skin contact between the mother and infant. This contact increases the risk that vaccinia virus from the mother’s vaccination site could be transmitted to the infant. (02/13/03) 
MMWR "Recommendations for Using Smallpox Vaccine in a Pre-Event Vaccination Program"  

Separating Live Vaccines

It is thought that a parenterally-administered live vaccine can interfere with replication of a second live vaccine administered after it. Therefore, ACIP recommends waiting for one replication cycle (i.e., one incubation period, i.e., about 4 weeks), and then repeating the second vaccine.

Yellow fever vaccine can be administered at any time after single-antigen measles vaccine. Ty21a (live, oral) typhoid vaccine and parenteral live vaccines (e.g., MMR, varicella, yellow fever) can be administered simultaneously or at any interval before or after eachother. (02/20/03) ACIP General Recommendations (see page 5)

Intervals Between Vaccine Doses

Remember, it's better to put more rather than less space between doses. Therefore, when scheduling appointments, the recommended interval should be your first choice, the minimum interval your second choice, and the 4-day grace period your last option. You will also need to check for compliance with applicable day care/school laws in your state. Some states do not accept the 4-day grace period. (02/13/03)  Back

Expired Vaccine

Remember, it is important to always recheck the vaccine label before you administer the vaccine. If it is expired, then remove it from the refrigerator or freezer so there is no risk of using it. Also, let’s be clear on the definition of “expired”. Sometimes these vials only contain a month and year. In that case, you can use the vaccine right up through the last day of the month printed on the vial or box. For example, if the vial says June, 2003, you can use the vaccine through the last day of June. It does not expire on the first day of the month, but definitely do not use it if it is even one day out of date. (02/13/03)  Back

Vaccines and PPD Testing

Measles vaccine (and possibly mumps, rubella, and varicella vaccines) may transiently suppress the response to PPD in a person infected with Mycobacterium tuberculosis. Simultaneously administering PPD and measles-containing vaccine does not interfere with reading the PPD result after 48-72 hours. If a measles-containing vaccine has already been given, delay PPD screening until at least 4 weeks after vaccination. This delay will remove any concern of suppressed PPD reactivity from the vaccine.

PPD screening can also be performed and read before administering a measles-containing vaccine. But this option is the least favored because it will delay receipt of the vaccine.

No data exist regarding PPD suppression with other parenteral live virus vaccines (e.g., varicella or yellow fever). In the absence of data, following guidelines for measles-containing vaccine when scheduling PPD screening and administering these vaccines is prudent. If the opportunity to vaccinate might be missed, vaccination should not be delayed because of these theoretical considerations.

Mucosally administered live vaccines (e.g., OPV and intranasally administered influenza vaccine) are unlikely to affect the response to PPD.

No evidence has been reported that inactivated vaccines, polysaccharide vaccines, recombinant, or subunit vaccines, or toxoids interfere with response to PPD.

The biological basis for separating a live vaccine and PPD if the vaccine is given first was revealed in the 1960s. It was observed that the early measles vaccine - the Edmonston vaccine - could suppress the response to a tuberculin skin test, the PPD. Cell mediated immunity is slightly suppressed by viral infections, including measles and measles vaccine. Cell mediated immunity to TB antigens is exactly what you're measuring with a PPD. If you give measles vaccine first, then place a PPD during the period of immune suppression, the response to the skin test may be reduced- even if the person DOES have TB. It's not known if the current, more attenuated vaccine also has this effect. But it’s safer to assume it does and not risk interference with the accurate reading of a PPD.

PPD and BCG Vaccine

There are two problems with BCG vaccine. First, it does not reduce the risk of being infected with Mycobacterium tuberculosis. What it probably does do is reduce the risk of disseminated disease among very young children with Mycobacterium tuberculosis. This is compounded by the fact that BCG is used where there are high rates of TB. If you have someone coming from someplace where there is a lot of TB, they should be tested with PPD. There is more information available about TB on CDC's Tuberculosis websiteBack

Latex Allergy

Latex is liquid sap from the commercial rubber tree. Latex contains naturally occurring impurities (e.g., plant proteins and peptides), which are believed to be responsible for allergic reactions. Latex is processed to form natural rubber latex and dry natural rubber. Dry natural rubber and natural rubber latex might contain the same plant impurities as latex but in lesser amounts. Natural rubber latex is used to produce medical gloves, catheters, and other products. Dry natural rubber is used in syringe plungers, vial stoppers, and injection ports on intravascular tubing. Synthetic rubber and synthetic latex also are used in medical gloves, syringe plungers, and vial stoppers. Synthetic rubber and synthetic latex do not contain natural rubber or natural latex, and therefore, do not contain the impurities linked to allergic reactions.

The most common type of latex sensitivity is contact-type (type 4) allergy, usually as a result of prolonged contact with latex-containing gloves. However, injection-procedure--associated latex allergies among patients with diabetes have been described. Allergic reactions (including anaphylaxis) after vaccination procedures are rare. Only one report of an allergic reaction after administering hepatitis B vaccine in a patient with known severe allergy (anaphylaxis) to latex has been published.  Back

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This page last modified on October 18, 2005


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