IMMUNIZATION IN SPECIFIC SITUATIONS
In following situations, immunization schedule has to be modified according to the needs and risk of complications.
Immunocompromised children are in greater need for vaccines due to susceptibility for infections but benefits may not be optimal due to poor immunological response.
Further, there is potential risk of developing active disease following administration of live vaccines. General rules of immunization in these children include that:• Live vaccines are contraindicated in severe immunodeficiency, but may be given in mild/moderate immunodeficiency, provided benefits outweigh the risks;
• Inactivated vaccines may be given but the protective value is unreliable and must be checked periodically
with antibody titers. If necessary, doses need to be repeated. Higher quantity or number of doses may be used in such cases, e.g. double-dose HBV.
• Household contacts of immunocompromised child should also be fully immunized to reduce the risk of exposure. However, they should not be given transmissible vaccines, e.g. OPV.
All routine vaccines, including live vaccines, may be given to asymptomatic HIV positive children without laboratory evidence of immunosuppression. However, live vaccines, e.g. BCG, OPV, measles and varicella are contraindicated in seropositive children with clinical AIDS or severely low CD4 counts. Inactivated vaccines are safe. IPV may be used instead of OPV in these cases (Ch 10.28).
Cancer chemotherapy: All live vaccines are contraindicated for 6 months after completion of therapy and inactivated vaccines may be given but should not be counted as valid doses. General considerations for immunization of a child on chemotherapy are as follows:
• No vaccine must be given during chemotherapy including pulse polio doses, except influenza (annual dose) and HBV (in unimmunized/partly immunized children).
• Influenza and varicella vaccines are also recommended for the contacts, who should not receive OPV including Pulse polio dose (replace with IPV, if needed). If given by mistake, contact sibling should remain away from cancer child for 2 weeks.
• Post-exposure prophylaxis for rabies must include passive prophylaxis for all bite categories and one additional dose of ARV at 90 days.
• Tetanus prophylaxis in wound care must include single Td dose irrespective of past immunization status, and tetanus immunoglobulins in all cases except in clean and minor wounds.
• Post-exposure varicella prophylaxis is must with VZIG, IVIG or high dose acyclovir in exposed children.
• Post-chemotherapy, immunization depends on the previous immunization status and should begin only after 6 months of completion of chemotherapy. While unimmunized or partially immunized children should receive catch-up immunization as usual, fully immunized children before chemotherapy should receive a single booster dose of age appropriate DPT, IPV, HBV, Hib, PCV, HAV, TCV, MMR and varicella. In children, who had received only OPV doses in the past, two IPV doses at one month interval are recommended.
Long-term steroid therapy: Efficacy of inactivated vaccines as well as safety and efficacy of live vaccines is doubtful in cases on prolonged corticosteroid therapy and general considerations for immunization in them are as follows:
• Children on low-dose systemic steroids or topical/ inhaled steroids may be safely and effectively immunized with all vaccines, as also those on any dose of steroids for lt; 2 weeks.
• Children on high-dose oral steroids (prednisolone gt; 2 mg/kg/day or 20 mg/day or equivalent) for more than 2 weeks should not receive live virus vaccines until steroids have been discontinued for one month.
• Children with other immunosuppressant medications, e.g. Rituximab or TNF-#945;, should not receive live virus vaccines during therapy, except in special circumstances.
Preterms and LBW: Three major concerns regarding immunizations of preterm and LBW infants include high-risk of infections, uncertain immunogenicity due to immature immune system and logistic problems to give a vaccine to very small child. Some basic considerations regarding immunization of these children are as follows:
• BCG and OPV must be administered at birth irrespective of the weight or gestation, after stabilization and before discharge. However, HBV birth dose should be delayed till one month of age in babies lt;2000 gm at birth due to doubtful immunogenicity, unless delivered to an HBsAg positive mother.
• All subsequent vaccines may be given as per chronologic age (even if still in hospital), except RV vaccine, which should be deferred until discharge to prevent the health care-associated spread of virus in nursery.
• Since preterm and low birth weight babies have low muscle mass, smaller and thinner needles must be used in them for intramuscular injections.
• All HCW dealing with these babies should be appropriately immunized.
Sick children: General considerations for immunization in sick children with acute or chronic diseases, are as follows:
• Vaccinations can be safely given during minor illnesses, e.g. URTI, mild diarrhea, etc.
• Vaccination may be postponed during moderate or severe acute illness to avoid conincidental problems, e.g. febrile seizures wrongly attributed to the vaccine. However parents should be instructed to visit for immunization as soon as the child is better.
• No vaccine is contraindicated in children with chronic systemic diseases. In fact, special vaccines may be required in some cases, e.g. HBV in chronic liver disease, pneumococcal and influenza vaccines in cardiopulmonary disease, etc.
• Children with hemorrhagic disorders, e.g. haemophilia, may be given injectable vaccines subcutaneously or intramuscularly with a thinner needle and applying
the firm pressure without rubbing over the site for 5-10 minutes.
In severe cases, vaccination may be given shortly after administration of clotting factor.Blood products as well as other antibody products, e.g. immunoglobulins, (e.g. IVIG) may inhibit the immune response to live vaccines for variable period of time. Some considerations for immunization in recipients of blood or antibody products are as follows:
• All except live vaccines can be administered simultaneously, before or after an antibody-containing product without any interval criteria, but at different sites.
• MR/MMR and varicella vaccines should not be given until 6 months after blood product transfusions (3 months after saline washed RBCs), 10 months after IVIG, and 3-4 months after other specific immunoglobulins. Administration of an antibodycontaining product within 14 days of MR/MMR or varicella vaccination might affect the vaccine uptake and the dose should be repeated after recommended time interval.
• Other live vaccines, e.g. yellow fever, Rotavirus vaccine, live attenuated influenza vaccine, and zoster vaccines may be given anytime.
• Low dose anti-D globulin to Rh-negative women is not an indication to defer rubella or varicella vaccination.
• HBV, TT/Td and ARV vaccines may be given simultaneously with corresponding immunogobulins but at different sites.
Solid organ transplant (SOT) recipients are immunocompromised even before the transplant due to the underlying disease and continue to be the same after procedure due to immunosuppressive therapy or graft rejection. Important considerations related to immunization for recipients are as follows:
• SOT recipients should complete all age-appropriate immunizations prior to the transplant, at least 2 weeks before the transplant (4 weeks for live vaccines), followed documentation of antibody titers. If required, varicella and MMR vaccines may be given even at 6-11 months of age.
• Post-transplant, live vaccines are contraindicated though catch-up immunization with other vaccines may be started after 6 months.
IIV can be given after 1-2 months of transplant and then annually. Antibody titers may be checked after 6 months to decide the need for boosters, e.g. HBV booster.• Household and health-care contacts of SOT recipients should be immunized with live vaccines, e.g. MMR, varicella etc and influenza to reduce the risk of
transmission.
Haematopoietic stem cell transplant (HSCT) recipients are virtually unimmunized due to loss of all memory responses during marrow ablation and need to be reimmunized. Basic considerations in immunization of these cases are as follows:
• Age-appropriate immunization of the donor and recipients should be completed, at least 4 weeks before for live vaccines and 2 weeks before inactivated vaccines.
• Post-HSCT, recipients should be considered as “never vaccinatedquot; regardless of pre-HSCT vaccination status and need to be re-immunized with all inactivated vaccines, after 6 months of procedure. However, IPV, Hib, PCV and IIV can be given after 3-4 months. Additional doses may be needed for HBV or PCV13.
• Live vaccines should not be administered to HSCT patients with active GVHD or ongoing immunosuppression. MMR and varicella vaccines may be administered after 24 months, if the recipient is presumed to be immunocompetent and 8-11 months after last dose of IVIG.
Splenic dysfunction due to congenital asplenia or secondary to sickle cell disease, splenectomy or radiation therapy render children susceptible for serious infections with encapsulated organisms and important immunization considerations in these cases are as follows:
• No vaccine, including live vaccines, is contraindicated and they should all receive all age-appropriate immunizations, with special emphasis on PCV, Hib, and typhoid vaccines.
• In addition, they should also receive: (a) two doses of MCV at 8 weeks interval after 2 years of age, (b) single dose of Hib vaccine, if not received till 5 years of age, (c) age-appropriate dose/s of PCV, and (d) asingle dose of PPSV after 8 weeks of PCV (and at least 2 weeks before surgery). PPSV must be repeated once after 5 years.
• For emergency splenectomy, vaccination should begin at least 2 weeks after the surgery rather than immediately, for better antibody response with: (a) MCV1, PCV and Hib (if not received earlier), followed after 8 week by (b) MCV2 and PPSV. PPSV must be repeated once after 5 years.
9.5