A senior Hong Kong health official has warned of a higher risk of influenza infection as vaccination rates fall and the city’s summer flu season stretches on, following the death of a second unvaccinated child from the virus. Centre for Health Protection controller Dr Edwin Tsui Lok-kin issued the warning as Hong Kong’s current flu season, which began in June, showed no sign of easing. He said authorities were monitoring possible changes in how the virus spreads after two consecutive summer flu...