Using Live, Attenuated Influenza Vaccine for Prevention and Control of Influenza

Using Live, Attenuated Influenza Vaccine for Prevention and Control of InfluenzaCDC MMWR. 2003;52:RR13:1 The FDA has approved FluMist, which is an intranasal, trivalent, cold-adapted, live, attenuated influenza vaccine (MedImmune Inc, Gaithersburg, MD). The vaccine was approved for healthy adults and children in the age of 5 to 49. The product is (1) attenuated so that it produces mild or no symptoms, (2) temperature-sensitive so that vaccine virus cannot replicate at the temperature of lower airways in humans, and (3) cold-adapted so that it replicates efficiently at 25°C. Similarities of the 2 vaccines are summarized in the following table:TableEfficacy: Control trials have shown this vaccine to be comparably effective compared to inactivated influenza vaccine (Vaccine. 2000;18:899; JAMA. 1999;282:137). Issues regarding live virus influenza vaccine include the following: Person-to-person transmission of the vaccine strain: 80% of recipients shed at least 1 strain for a mean of 7.6 days. The estimated probability of acquiring it through close contact is 0.6% to 2.4%. Stability: The vaccine strain has remained phenotypically stable in the studies to date. Recommendations: ˆInactivated vaccines is recommended for persons over 6 months who are at high risk for complications from influenza due to age or the presence of defined medical conditions and those who are in close contact with persons at high risk. ˆVaccine is recommended for anyone who requests it; this would include healthy persons of age 5 to 49. Vaccine could be either live or inactivated. Contraindications: (1) persons under 5 years or over 50 years; (2) selected diseases including asthma, pulmonary/cardiovascular disease, underlying medical conditions including diabetes, renal failure, and hemoglobinopathies, persons with immunodeficiency; (3) patients with a history of Guillain-Barre syndrome; (4) pregnancy; (5) allergy to the vaccine components or eggs. Time for vaccination: The optimal time is usually October or November. Dosing recommendations: Children 5 to 8 years who are previously unvaccinated should receive 2 doses separated by 6 to 10 weeks; persons 9 to 49 years should receive a single dose. Storage: It must be stored at −15°C or colder. It should not be refrozen after thawing. Side effects: In adults, nasal congestion is noted in 28% to 78%, headache in 16% to 44%, and sore throat in 15% to 27% (J Infect Dis. 2000;181:725).