Weekly incidence by age group. Highlighted areas show school holidays (taken from http://www.halftermdates.co.uk/ and may not be representative of entire population). The lower panel shows the proportion of samples testing positive for Influenza A and Influenza B. The Respiratory DataMart System is a laboratory surveillance tool to monitor influenza and other respiratory viruses based on collated lab results from a network of Public Health England (PHE) and NHS laboratories in England. Respiratory swabs from primary and secondary care are tested for a variety of viruses using real time polymerase chain reaction (RT-PCR) assays. Weekly results are published in the PHE National Influenza Report (http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/SeasonalInfluenza/EpidemiologicalData/03influsweeklyreportpdfonly/) First week of reporting is not included as responses may include all cases of ILI since the previous season.