Repeated influenza vaccination of healthy children and adults: borrow now, pay later?
A growing number of publications are recommending annual influenza vaccination of healthy children and adults. However, the long-term consequences of repeated influenza vaccination are unknown. We used a simple model of recurrent influenza infection to assess the likely impact of various repeated influenza vaccination scenarios. The model was based on a Markovian framework and was fitted on annual incidence rates of influenza infection by age. We found that natural influenza infection reduced the risk of being re-infected by 15.4% (95% confidence interval 7.1-23.0). Various scenarios of repeated influenza vaccination were then simulated and compared with a reference scenario where vaccination is given from age 65 years onwards. We show that repeated vaccination at a young age substantially increases the risk of influenza in older age, by a factor ranging between 1.2 (vaccination after 50 years) to 2.4 (vaccination from birth). These findings have important implications for influenza vaccination policies.
Carrat
F
F
Epidemiology and Information Sciences, U707, Institut national de la Santé et de la Recherche Médicale, Paris, France. carrat@u707.jussieu.fr
Lavenu
A
A
Cauchemez
S
S
Deleger
S
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D008390:Markov Chains; D008875:Middle Aged; D008962:Models, Theoretical; D012008:Recurrence; D012307:Risk Factors
D007252:Influenza Vaccines