Abstract
Background: Understanding the immune response to natural infection by SARS-CoV-2 is key to pandemic management, especially in the current context of emerging variants. Uncertainty remains regarding the efficacy and duration of natural immunity against reinfection.
Methods: We conducted an observational prospective cohort study in Canadian healthcare workers (HCWs) with a history of PCR-confirmed SARS-CoV-2 infection to (i) measure the average incidence rate of reinfection and (ii) describe the serological immune response to the primary infection.
Results: Our cohort comprised 569 HCWs; median duration of individual follow-up was 371 days. We detected six cases of reinfection in absence of vaccination between August 21, 2020, and March 1, 2022, for a reinfection incidence rate of 4.0 per 100 person-years. Median duration of seropositivity was 415 days in symptomatics at primary infection compared with 213 days in asymptomatics (p < 0.0001). Other characteristics associated with prolonged seropositivity for IgG against the spike protein included age over 55 years, obesity, and non-Caucasian ethnicity.
Conclusions: Among unvaccinated healthcare workers, reinfection with SARS-CoV-2 following a primary infection remained rare.
Keywords: COVID-19; SARS-CoV-2; prospective studies; reinfection; serology.
【저자키워드】 COVID-19, SARS-CoV-2, serology, Reinfection, prospective studies, 【초록키워드】 IgG, Efficacy, immune response, vaccination, pandemic, serology, SARS-COV-2 infection, obesity, prospective cohort study, variants, healthcare worker, Spike protein, Cohort, Characteristics, HCWs, management, healthcare, incidence rate, Seropositivity, understanding, age, Follow-up, Uncertainty, natural infection, serological, Other, Primary infection, natural immunity, PCR-confirmed, average, remained, conducted, median, absence, the spike protein, 【제목키워드】 healthcare worker, Cohort, estimation,