Southern Hemisphere Influenza and Vaccine Effectiveness Research and Surveillance

Huang, Qiu Sue; Turner, Nikki; Baker, Michael G; Williamson, Deborah A; Wong, Conroy; Webby, Richard; Widdowson, Marc-Alain

Influenza disease burden data are essential to allocate limited health resources, assist influenza vaccination policy development and improve vaccine uptake, particularly for subpopulations at risk. However, the evidence to support valid and precise estimates of influenza disease burden globally remains weak with low quality, partly due to the short duration of studies and the heterogeneity of study settings and methods (statistical modelling, active versus passive case findings, virological versus clinical detection). [8] [9] [10] [11] [12] [13] [14] In addition, there is scarce information on sero-epidemiologic investigation of seasonal influenza at a population level. Serology can detect both symptomatic and asymptomatic infections, thus estimating the true incidence of influenza infection. This parameter cannot be determined by either disease surveillance programmes or detection of virologically confirmed cases as they would vastly underestimate influenza incidence and overestimate severity. [15] [16] [17] [18] SHIVERS allows calculation of rates of infection and different clinical presentations in the same population at the same time for an accurate picture of the relative severity of influenza infection in the population and vulnerable subpopulations at four levels: (a) severe hospitalized disease; (b) moderate disease requiring a general practice visit; (c) mild disease not requiring a general practice visit; (d) incidence of infection (symptomatic and asymptomatic).