Abbreviations: RSV: respiratory syncytial virus; HMPV: human
metapneumovirus; PIV: parainfluenza virus.
a Attributable fraction calculated for individuals
aged <5, 5-44 and ≥45 years of age and used to adjust the
observed positivity proportion among individuals aged <1 and
1-4; 5-24 and 25-44 ; and 45-64 and ≥65 years, respectively.