Group A Streptococcus among American Indian Persons, White Mountain Apache Tribal Lands, United States, 2016-2019.

American Indian populations have higher rates of invasive disease because of group A Streptococcus (GAS). This study describes the rates of severe and invasive GAS (siGAS) infections and the distribution of circulating emm types among nonsevere and siGAS cases in the White Mountain Apache Tribal lands in Arizona, USA, during 2016-2019. Isolates underwent whole-genome sequencing to determine emm type. Among siGAS cases, 36% of patients were female, the median age was 40.7 years, and 47.2% of patients were co-infected with Staphylococcus aureus. The age-standardized incidence rate during 2018-2019 was 554.2/100,000 persons. Among the pharyngitis isolates from 2017-2018, the most common emm types were 82 (36.3%), 6 (22.2%), and 60 (16.3%). Among the siGAS cases in 2017-2019, the most common emm type was 82 (65.5%) in the first year and 91 (36.2%) in the second year. Interventions are needed to address the high rates of GAS disease in this population.