Effects of attenuated influenza virus administration to young children on pneumococcal density and acquisition in UK families: a randomised controlled trial

Summary: Background: The live attenuated influenza vaccine (LAIV) is offered in the UK to young children, protecting against influenza for those vaccinated, and as an indirect protection for the wider community. LAIV has also been shown to increase carriage density of Streptococcus pneumoniae , to an extent, in children. This study sought to confirm whether the vaccine, as a viral proxy, leads to an increase in carriage density in children and, if so, whether this increase augments S pneumoniae acquisition in household contacts.