Background
The COVID-19 pandemic has affected respiratory disease epidemiology. Measures to reduce transmission of SARS-CoV-2 (e.g., masking, social distancing, school closures) have reduced the incidence of common infectious diseases. Changes in rates of GAS pharyngitis have not been published.
Methods
Clinical pharyngeal specimens tested for GAS via LAMP methodology (loop-mediated isothermal amplification of GAS DNA) or rapid antigen tests (RADTs) from January 2019 to December 2021 at our children’s hospital were analyzed. Negative RADTs were confirmed by LAMP; patients were considered test-positive if either test was positive regardless of clinical symptoms. Annual positivity rates were compared using statistical process control (SPC) charts with both 2019 and 2020 as baseline years. The change in GAS incidence rate (positive patients/1000 tested) between years was assessed via chi-square tests.
Results
6,538 patients had throat swabs tested for GAS from January 2019 through December 2021. Using SPC with 2019 as a baseline, there was a 10.2% decrease in mean GAS positivity through 2021. With 2020 as baseline, there was a 12.0% decrease in mean GAS positivity through 2021. There was a significant relationship between year and incidence of positive GAS tests: 2019 vs. 2020-21 (x2 = 34.48, p <=0.001) and 2020 vs. 2021 (x2 = 82.68, p <=0.001).
Conclusions
Using throat swab results, the incidence of GAS pharyngitis has decreased significantly during the COVID-19 pandemic. Implications: Pandemic-related risk mitigation measures were associated with decreased incidence of GAS pharyngitis. It is likely that GAS colonization and invasive infections were also affected.