Table 6.

 Specific recommendations for influenza surveillance and burden of disease studies in Africa during the 2009 H1N1 pandemic

Influenza virus infection incidence in the community	Serologic tests are useful to determine the approximate proportion of persons in a community infected by influenza virus
Study design	• Prospective, paired serologic surveys before and after the first and subsequent waves of the pandemic • Cross sectional serologic surveys after the first and subsequent waves of the pandemic
Population	• Ideally, well described populations with high risk groups over‐represented.
Specimen collection criteria	• All persons included without specimen collection criteria
Laboratory testing	• 2009 H1N1 specific hemagglutination inhibition assay
Outcomes measured	• Evidence of influenza virus infection by serology
Analysis	• Incidence of infection within a community (population based, if possible), incidence of infection by age group and by chronic disease diagnosis
Burden of severe influenza illness	Sentinel surveillance in health care settings (outpatient clinics and hospitals) can help to understand the proportion of severe illness associated with infection.
Study design	• Prospective surveillance
Population	• Outpatient clinics and hospitals
Specimen collection criteria	• Influenza‐like illness for clinic patients Fever >38·0° AND (cough or sore throat) 50 • Severe Acute Respiratory Illness for hospitalized patients Fever >38·0° AND (cough or sore throat) AND difficult breathing 18
Laboratory testing	• RT‐PCR assay for evidence of active 2009 H1N1 virus infection
Outcomes measured	• Medically attended, laboratory confirmed, influenza‐associated illness
Analysis	• Incidence of influenza illness requiring outpatient care or hospitalization
Other studies
Vaccine effectiveness	• Licensed influenza vaccine compared to inactive comparator vaccine with robust prospective surveillance for medically attended, laboratory confirmed, influenza‐associated illness • Vaccine probe studies; control group can provide data on disease burden
Risk factors of disease	• Collection of epidemiologic and clinical data to determine risk factors for severe disease among persons in community incidence studies or burden of severe illness studies
Costs to society	• Collection of cost of care data as part of influenza burden of illness studies; direct and indirect costs

Many additional methodologies exist to investigate influenza burden of disease. The above study designs are not exhaustive, but they do represent the authors’ recommendations for the preferred study methodologies given resource limitations.