Invasive Group A Streptococcal Disease in Persons Experiencing Postpandemic Homelessness in Canada

Area of Science:

• Infectious Diseases
• Epidemiology
• Public Health

Background:

• Invasive group A streptococcal (iGAS) infections and the number of persons experiencing homelessness (PEH) are both increasing.
• Understanding the epidemiology of iGAS infections among PEH is crucial for developing effective protection strategies.

Purpose of the Study:

• To assess the impact of the post-COVID-19 pandemic resurgence of iGAS infections on PEH.
• To compare the incidence, risk factors, clinical presentation, outcomes, and infecting strains of iGAS between PEH and housed populations.

Main Methods:

• A cross-sectional study utilizing population-based iGAS surveillance data from January 2022 to December 2023 in Toronto and Peel Region, Canada.
• Data on emm typing, population denominators, and clinical characteristics were collected and analyzed.

Main Results:

• iGAS incidence was 70.7-fold higher among PEH compared to housed persons.
• PEH were more likely to have iGAS presenting as soft tissue infections and less likely to be immunocompromised.
• Specific emm types were disproportionately associated with iGAS infections in PEH compared to housed individuals.

Conclusions:

• The post-pandemic resurgence of iGAS infections significantly affects PEH, with higher incidence and distinct epidemiological characteristics.
• Differences in risk factors, presentation, and infecting strains highlight the need for tailored prevention and intervention strategies for PEH.
• Development of improved iGAS protection, such as vaccines, is urgently needed for the PEH population.