Disease burden manual
WHO’s Manual for estimating disease burden associated with seasonal influenza  provides a comprehensive assessment of disease burden associated with the respiratory manifestations of influenza – i.e. influenza-like illness (ILI), severe acute respiratory infection (SARI) and hospitalized severe acute lower respiratory illness (ALRI). The manual can help countries obtain a conservative estimate, based on a proportion of the overall disease burden associated with influenza, using existing data sources and taking into account their limitations. When introducing maternal influenza vaccination, the manual can serve to estimate the influenza disease burden and can help identify areas where sentinel influenza surveillance can be established or improved.