# Post-pandemic increase of Group A streptococcal infections in adults: a retrospective cohort study from 2012 to 2024

## TL;DR

This study shows that Group A streptococcal infections increased in adults after the pandemic, similar to what was seen in children.

## Contribution

The study provides new evidence on the post-pandemic rise of GAS infections specifically in adult populations.

## Key findings

- There was a significant increase in hospitalized adult patients with GAS infections post-pandemic (IRR 2.94).
- ICU admissions for GAS infections also rose significantly (IRR 2.5) after pandemic restrictions were lifted.
- The increase in GAS infections among adults persisted into 2024 without returning to pre-pandemic levels.

## Abstract

After the COVID-19 pandemic an increase in Group A streptococcal (GAS) infections was reported mostly for children in several countries worldwide. However, data on infections in adults remain limited. Therefore, we focus on the pre- and post-pandemic incidence of GAS infections in adults, the need for intensive care treatment and the microbiological sampling patterns.

We performed a retrospective cohort study of hospitalized adult patients from 2012 to 2024, based on a positive GAS detection in their routine microbiological sampling. We compared the post-pandemic phase after lifting the isolation measures in April 2022 to the pandemic and pre-pandemic phase. Additionally, we analysed positive rapid assessment tests in children, indicative of the prevalence of GAS tonsillitis in this population.

In the post-pandemic months, we observed a significant increase in overall hospitalized adult patients (IRR 2.94) and ICU patients (IRR 2.5) with GAS infections. The rise can be attributed to an increase in both invasive and non-invasive GAS detections.

The increase in GAS infections is not only relevant in paediatric patients, but also has significant relevance in adult patients. Physicians need to be aware of this increase. The data of 2024 show a sustained increase and an incidence that has not returned to pre-pandemic levels.