Abstract Following the re-introduction of influenza A(H1N1) in 1978, which spread widely amongst children and younger people, Public Health England (PHE) and Medical Officers of Schools Association (MOSA) developed a surveillance scheme to monitor respiratory illness in children attending MOSA (a network of private and boarding) schools. Since 1983, the scheme has formed part of the routine surveillance activities of PHE. A recent objective of this scheme is to evaluate the association between influenza vaccination policies in MOSA schools and the epidemiology of influenza. This study presents the results from the 2016/17 influenza season.Participating MOSA schools are required to complete a general annual online survey, including questions on influenza vaccine policies for students, weekly surveys reporting how many boarders developed influenza-like-illness (ILI) and a vaccine uptake survey by school year.“Vaccinating schools” are defined as schools offering influenza vaccine to all healthy and high risk boarders and “non-vaccinating schools” as offering influenza vaccine to high risk boarders only. Sixteen schools participated (with more than 5,000 pupils aged 6 to 18 years of age) in 2016/17. The vaccination survey was completed by 15 of the 16 (94%) participating schools. Overall vaccine uptake amongst all boarders in vaccinating schools (n=2) was 65.6% and 10.6% in non-vaccinating schools. Fourteen ILI cases were reported in vaccinating schools in secondary school age boarders (8.3 per 1,000 boarders) compared to 118 cases in non-vaccinating schools (41.5 per 1,000 boarders), (RR = 0.12, 95% CI 0.06 to 0.20) over the period of week 40 2016 to week 20 2017. The 2016/17 season, dominated by influenza A(H1N1)pdm09, had significantly less ILI cases reported in schools offering vaccine to all boarders compared to non-vaccinating schools. Reaching uptake levels above 60% in secondary boarders has school level benefits in reducing rates of ILI illness. Funding This scheme is funded by PHE.