Birth Month Linked to Timing of Influenza Vaccination in Young Children

THURSDAY, Feb. 22, 2024 (HealthDay News) -- For young children, birth month is associated with timing of influenza vaccination, according to a study published online Feb. 21 in The BMJ.

Christopher M. Worsham, M.D., M.P.H., from Harvard Medical School in Boston, and colleagues examined optimal timing of influenza vaccination in young children in a population-based cohort study conducted among commercially insured children aged 2 to 5 years who were vaccinated against influenza during 2011 to 2018.

A total of 819,223 children aged 2 to 5 years received influenza vaccination during the study period. The researchers found that children who were vaccinated in November and December were the least likely to have an influenza diagnosis; the finding may have been confounded by unmeasured factors influencing vaccination timing and influenza risk. Vaccination often occurred on days of preventive care visits and during birth months; children born in October were disproportionately vaccinated during October and were vaccinated later and earlier than those born in August and December, respectively. The lowest rate of influenza diagnosis was seen for children born in October (e.g., 2.7 percent versus 3.0 percent for those born in August; adjusted odds ratio, 0.88).

"The findings support current recommendations that children be vaccinated in October preceding a typical influenza season," the authors write.

One author disclosed ties to pharmaceutical companies.

Abstract/Full Text