Data from: Indirect protection from vaccinating children against influenza in households

Vaccination is an important intervention to prevent influenza virus
infection, but indirect protection of household members of vaccinees is
not fully known. Here, we analyze a cluster household randomized control
trial, with one child in each household randomized to receive vaccine or
placebo, for an influenza B epidemic in Hong Kong. We apply statistical
models to estimate household transmission dynamics and quantify the direct
and indirect protection of vaccination. Direct vaccine efficacy is 71%.
The infection probability of unvaccinated household members in vaccinated
households was only 5% lower than in control households, because only 10%
of infections are attributed to household transmission. Even when that
proportion rises to 30% and all children are vaccinated, we predict that
the infection probability for unvaccinated household members is only
reduced by 20%. This suggests that benefits of individual vaccination
remain important even when other household members are vaccinated.