Here, we report the retrospective epidemiological and microbiological investigation into this suspected outbreak of iGAS type emm66 occurring 2013-2015 in Sweden.

In 2013, the first case of invasive group A streptococcus (iGAS) type emm66 disease was identified within the national surveillance program in Sweden. From notifications made to the national notifiable disease system and from data obtained from the microbiological surveillance program, we identified 32 patients between 2013 and 2015 with iGAS type emm66 infection. Information on possible geographic links and lifestyle risk factors were collected from medical records and the genomes of the isolates were sequenced. Here, we report the retrospective epidemiological and microbiological investigation into this suspected outbreak of iGAS type emm66 occurring 2013-2015 in Sweden.