Rapid spread of pneumococcal nonvaccine serotype 7C previously associated with vaccine serotype 19F, England and Wales

Abstract

We observed a sudden and rapid increase in rare invasive pneumococcal disease serotype 7C, from an annual average of 3 cases during 2000–01 through 2015–16 to 29 cases in 2016–17. The increase was caused almost entirely by clonal expansion of sequence type 177, previously associated with vaccine serotype 19F.