Coordination of multidisciplinary resources for vaccination of egg-allergic individuals during an H1N1 (novel) influenza pandemic

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2023–24 Influenza Season

This report updates the 2022–23 recommendations of the Advisory Committee on Immunization Practices (ACIP) concerning the use of seasonal influenza vaccines in the United States (

MMWR Recomm Rep 2022;71[No. RR-1]:1–28). Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. All seasonal influenza vaccines expected to be available in the United States for the 2023–24 season are quadrivalent, containing hemagglutinin (HA) derived from one influenza A(H1N1)pdm09 virus, one influenza A(H3N2) virus, one influenza B/Victoria lineage virus, and one influenza B/Yamagata lineage virus. Inactivated influenza vaccines (IIV4s), recombinant influenza vaccine (RIV4), and live attenuated influenza vaccine (LAIV4) are expected to be available.

For most persons who need only 1 dose of influenza vaccine for the season, vaccination should ideally be offered during September or October. However, vaccination should continue after October and throughout the season as long as influenza viruses are circulating and unexpired vaccine is available. Influenza vaccines might be available as early as July or August, but for most adults (particularly adults aged ≥65 years) and for pregnant persons in the first or second trimester, vaccination during July and August should be avoided unless there is concern that vaccination later in the season might not be possible. Certain children aged 6 months through 8 years need 2 doses; these children should receive the first dose as soon as possible after vaccine is available, including during July and August. Vaccination during July and August can be considered for children of any age who need only 1 dose for the season and for pregnant persons who are in the third trimester during these months if vaccine is available

ACIP recommends that all persons aged ≥6 months who do not have contraindications receive a licensed and age-appropriate seasonal influenza vaccine. With the exception of vaccination for adults aged ≥65 years, ACIP makes no preferential recommendation for a specific vaccine when more than one licensed, recommended, and age-appropriate vaccine is available. ACIP recommends that adults aged ≥65 years preferentially receive any one of the following higher dose or adjuvanted influenza vaccines: quadrivalent high-dose inactivated influenza vaccine (HD-IIV4), quadrivalent recombinant influenza vaccine (RIV4), or quadrivalent adjuvanted inactivated influenza vaccine (aIIV4). If none of these three vaccines is available at an opportunity for vaccine administration, then any other age-appropriate influenza vaccine should be used

Primary updates to this report include the following two topics: 1) the composition of 2023–24 U.S. seasonal influenza vaccines and 2) updated recommendations regarding influenza vaccination of persons with egg allergy. First, the composition of 2023–24 U.S. influenza vaccines includes an update to the influenza A(H1N1)pdm09 component. U.S.-licensed influenza vaccines will contain HA derived from 1) an influenza A/Victoria/4897/2022 (H1N1)pdm09-like virus (for egg-based vaccines) or an influenza A/Wisconsin/67/2022 (H1N1)pdm09-like virus (for cell culture-based and recombinant vaccines); 2) an influenza A/Darwin/9/2021 (H3N2)-like virus (for egg-based vaccines) or an influenza A/Darwin/6/2021 (H3N2)-like virus (for cell culture-based and recombinant vaccines); 3) an influenza B/Austria/1359417/2021 (Victoria lineage)-like virus; and 4) an influenza B/Phuket/3073/2013 (Yamagata lineage)-like virus. Second, ACIP recommends that all persons aged ≥6 months with egg allergy should receive influenza vaccine. Any influenza vaccine (egg based or nonegg based) that is otherwise appropriate for the recipient’s age and health status can be used. It is no longer recommended that persons who have had an allergic reaction to egg involving symptoms other than urticaria should be vaccinated in an inpatient or outpatient medical setting supervised by a health care provider who is able to recognize and manage severe allergic reactions if an egg-based vaccine is used. Egg allergy alone necessitates no additional safety measures for influenza vaccination beyond those recommended for any recipient of any vaccine, regardless of severity of previous reaction to egg. All vaccines should be administered in settings in which personnel and equipment needed for rapid recognition and treatment of acute hypersensitivity reactions are available

This report focuses on recommendations for the use of vaccines for the prevention and control of seasonal influenza during the 2023–24 influenza season in the United States. A brief summary of the recommendations and a link to the most recent Background Document containing additional information are available at

https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/flu.html . These recommendations apply to U.S.-licensed influenza vaccines used according to Food and Drug Administration–licensed indications. Updates and other information are available from CDC’s influenza website ( https://www.cdc.gov/flu ). Vaccination and health care providers should check this site periodically for additional information.

Vaccination in children with allergy to non active vaccine components

Childhood immunisation is one of the greatest public health successes of the last century. Vaccines contain an active component (the antigen) which induces the immune response. They may also contain additional components such as preservatives, additives, adjuvants and traces of other substances. This review provides information about risks of hypersensitivity reactions to components of vaccines. Furthermore, recommendations to avoid or reduce reactions to vaccine components have been detailed.

Drug and vaccine allergy

Most children with a history of penicillin allergy are labeled allergic and denied treatment with penicillin and sometimes other beta-lactam antibiotics. Most of these children never were or are no longer allergic to penicillin. Penicillin skin testing and oral challenge can identify patients who are not currently allergic, allowing them to be treated with penicillin. Children with egg allergy are often denied influenza vaccination, because the vaccine contains a small amount of egg protein. However, recent studies have demonstrated that children with even severe egg allergy can safely receive the vaccine, reducing their risk of the morbidity and mortality associated with influenza.

Potential food allergens in medications

Excipients are substances in pharmaceuticals other than the active ingredients. Some excipients are foods or substances derived from foods, raising the possibility that these substances would pose a hazard to patients with food allergy. This review describes which food-derived substances are used as pharmaceutical excipients in which medications and reviews published data regarding the safety of the administration of these medications to recipients with food allergy. Such reactions are rare, usually because the amount of food protein is not present in a large enough quantity to elicit a reaction. When a food protein appears as an unintentional contaminant, the amount, if any, that is present might be variable and might elicit reactions only from some lots of medication or only in some patients. In most circumstances these medications should not be routinely withheld from patients who have particular food allergies because most will tolerate the medications uneventfully. However, if a particular patient has had an apparent allergic reaction to the medication, potential allergy to the food component should be investigated.

Administering influenza vaccine to egg-allergic persons

The most serious form of type I or IgE-mediated hypersensitivity reaction is anaphylaxis. A standardized case definition of anaphylaxis as an adverse event after immunization has been developed. Such reactions to vaccines, including influenza vaccine, are rare but potentially life-threatening. Until recently, all influenza vaccines were manufactured in eggs. Residual egg protein in the vaccines was thought to pose a risk to egg-allergic vaccine recipients. However, a large number of recent studies have demonstrated that egg-allergic recipients are no more likely than those without egg allergy to suffer such reactions. Published guidelines have been updated to recommend that patients with egg allergy receive annual influenza vaccination. Any patient who has an anaphylactic reaction to influenza vaccine should be carefully evaluated by an allergist for guidance on subsequent immunization.

A review of a paediatric emergency department vaccination programme for patients at risk of allergy/anaphylaxis

AIM

We sought to review the clinical outcomes of patients referred to our emergency department (ED) vaccination service for children with a history of allergy or anaphylaxis or in whom there was a concern of a significant adverse reaction.

METHODS

This was a prospective observational cohort study set in an urban tertiary Paediatric ED. All attendances for any childhood vaccination for a 5-year period (from January 1, 2006 to December 31, 2010) were included. Our primary outcome measure was any adverse reaction as a result of the vaccine administered.

RESULTS

A total of 446 vaccines were administered during the study period in 374 patients. Of these vaccinations, 310 (69.5%) were Measles, Mumps, Rubella (MMR). The majority of patients (348, 93%) were referred from the community. Suspected egg allergy was the reason for the majority of referrals for MMR (261/310 (84.2%)). Only six patients (1.3%) experienced an immediate reaction to a vaccination. All reactions were minor.

CONCLUSION

This is one of the largest studies looking at childhood vaccinations performed in a hospital setting for children who are 'at risk' of allergy, anaphylaxis or hypersensitivity. A significant number of referrals were unwarranted and the majority could have been safely managed in the community.