Question What vaccination sequence is associated with the best protection against influenza for children? Findings In this case-control study including 7533 children, vaccine effectiveness against medically attended, laboratory-confirmed influenza was higher among children who received the recommended number of doses compared with children who did not receive the recommended number of doses. Vaccine-naive children aged 2 years or younger who received 2 doses of influenza vaccine in their first vaccination season were less likely to test positive for influenza than those who received 1 dose. Meaning Results of this study suggest that the burden of influenza among young children in the US might be reduced by improving adherence to an initial 2-dose series of influenza vaccination in previously unvaccinated children.
Citation Chung JR, Flannery B, Gaglani M, et al. Patterns of Influenza Vaccination and Vaccine Effectiveness Among Young US Children Who Receive Outpatient Care for Acute Respiratory Tract Illness. JAMA Pediatr. Published online May 04, 2020. doi:10.1001/jamapediatrics.2020.0372