Population-level factors predicting variation in influenza vaccine uptake among adults and young children in England, 2015/16 and 2016/17.

England's influenza vaccination programme targets persons with clinical risk factors, pregnant women, those aged 65 years and older and children. Low vaccine uptake amongst primary school children was previously found to be significantly associated with increasing deprivation, Black or Minority Ethnic (BME) and certain religions. It is unknown whether these population predictors are associated with vaccine uptake in other groups. GP level data for target groups during the 2015/16 and 2016/17 seasons were linearly regressed against various factors to determine potential predictors associated with variation in uptake. Adjusted uptake for 2-4 year olds during both seasons was more than 11% lower in the most deprived decile and more than 3% lower in 34%+ BME populations compared to the least deprived and non-BME populations. Pregnant women in deprived areas had significantly lower vaccine uptake than in non-deprived areas. Patients 16-64 years old at risk showed no significant variation in uptake by deprivation, whereas patients 65 years and older had more than 3% higher vaccine uptake in the least deprived populations than the most deprived populations. Areas with the highest Muslim and BME populations had a significantly higher vaccine uptake among patients ages 16 to under 65 years old in a clinical risk group than non-Muslim and non-BME populations during both seasons. Population-factors have different effects on vaccine uptake for the various target groups. These findings support segmenting public health activities to improve vaccine uptake and reduce inequalities.