Resurgence of scarlet fever in England, 2014–16: a population-based surveillance study

Summary Background After decades of decreasing scarlet fever incidence, a dramatic increase was seen in England beginning in 2014. Investigations were launched to assess clinical and epidemiological patterns and identify potential causes. Methods In this population-based surveillance study, we analysed statutory scarlet fever notifications held by Public Health England from 1911 to 2016 in England and Wales to identify periods of sudden escalation of scarlet fever. Characteristics of cases and outbreaks in England including frequency of complications and hospital admissions were assessed and compared with the pre-upsurge period. Isolates from throat swabs were obtained and were emm typed. Findings Data were retrieved for our analysis between Jan 1, 1911, and Dec 31, 2016. Population rates of scarlet fever increased by a factor of three between 2013 and 2014 from 8·2 to 27·2 per 100 000 (rate ratio [RR] 3·34, 95% CI 3·23–3·45; p emm types with emm 3 (43%), emm 12 (15%), emm 1 (11%), and emm 4 (9%) being the most common. Longitudinal analysis identified 4-yearly periodicity in population incidence of scarlet fever but of consistently lower magnitude than the current escalation. Interpretation England is experiencing an unprecedented rise in scarlet fever with the highest incidence for nearly 50 years. Reasons for this escalation are unclear and identifying these remains a public health priority. Funding None.