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

In 2012, we began active, prospective, continuous, population-based surveillance for influenza and other respiratory pathogens among persons residing in the two DHBs hospitalized for respiratory disease (Figure 2 ). Research nurses reviewed daily records of all overnight acutely admitted inpatients to identify any inpatient with a suspected acute respiratory illness (ARI). They interviewed these patients by applying the World Health Organization (WHO) interim SARI case definition: 'an acute respiratory illness with a history of fever or measured fever of ≥38°C, and cough, and onset within the past 7 days, and requiring inpatient hospitalization'. 61 Since 2013, the WHO final SARI case definition has been used with onset changed from '7 days' to '10 days'. The patients were differentiated into SARI cases (those who met the SARI case definition) and non-SARI patients (those with ARI who did not meet the SARI case definition). A case report form captured information on demography, history of presenting illness, comorbidities, influenza vaccination history, disease outcome and risk factors. 60 If a patient met the SARI case definition, a respiratory specimen (nasopharyngeal swab or aspirate) was collected and tested simultaneously for influenza and other respiratory viruses by real-time reverse transcription (RT) polymerase chain reaction (PCR) techniques: influenza virus, respiratory syncytial virus (RSV), rhinovirus, parainfluenza virus types 1-3, adenovirus and human metapneumovirus ( Figure 3) . 60 A systematic sample of about 50% of non-SARI patients were also interviewed and provided a respiratory sample, in addition to those from whom a specimen was collected for clinical purposes. Some SARI cases and non-SARI patients were also tested for clinical purposes for a range of respiratory bacteria (e.g. Streptococcus pneumonia,