The following is a summary of “Enhancing detection of SARS-CoV-2 re-infections using longitudinal sero-monitoring: demonstration of a methodology in a cohort of people experiencing homelessness in Toronto, Canada, published in the February 2024 issue of Infectious Diseases by Richard et al.
Precise assessment of SARS-CoV-2 re-infection is vital for comprehending the link between infection rates and adverse consequences. However, exclusive dependence on PCR testing leads to underreporting.
Researchers conducted a retrospective study to compare the efficacy of longitudinal serologic data integration with testing alone among individuals experiencing homelessness in assessing SARS-CoV-2 re-infection.
They enrolled 736 individuals experiencing homelessness in Toronto, Canada, from June to September 2021. Over a 12-month follow-up, participants completed surveys and provided saliva and blood serology samples every three months. Re-infections were defined as positive PCR or rapid antigen test (RAT) results exceeding 90 days post-initial infection, new serologic evidence in individuals with prior infection who sero-reverted, or increased anti-nucleocapsid in seropositive individuals experiencing declining levels.
The results showed that of 381 participants at risk, 37 re-infections were detected through PCR/RAT, while 98 re-infections were identified through longitudinal serology. The comprehensive method revealed 37.4 re-infection events per 100 person-years, surpassing the rate detected by PCR/RAT alone (9.0 events/100 person-years) by more than four-fold. Almost all test-confirmed re-infections (85%) were also identifiable by longitudinal serology.
Investigators concluded that Longitudinal serology unlocks more SARS-CoV-2 re-infections, highlighting multi-data approaches for impactful research and public health.
Source: bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-024-09013-9
