Rates of COVID-19 Among Unvaccinated Adults With Prior COVID-19

Risk of SARS-CoV-2 reinfection among unvaccinated people with prior COVID-19 is a subject of debate.1,2 We performed a survival analysis in a large US population to assess the degree and duration of protection associated with natural immunity in unvaccinated individuals MethodsThis cohort study used data from patients tested for SARS-CoV-2 at 1300 sites of care …

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Risk of SARS-CoV-2 reinfection and COVID-19 hospitalisation in individuals with natural and hybrid immunity: a retrospective, total population cohort study in Sweden

Real-world evidence supporting vaccination against COVID-19 in individuals who have recovered from a previous SARS-CoV-2 infection is sparse. We aimed to investigate the long-term protection from a previous infection (natural immunity) and whether natural immunity plus vaccination (hybrid immunity) was associated with additional protection. MethodsIn this retrospective cohort study, we formed three cohorts using Swedish …

Continue reading Risk of SARS-CoV-2 reinfection and COVID-19 hospitalisation in individuals with natural and hybrid immunity: a retrospective, total population cohort study in Sweden

Risk and severity of SARS-CoV-2 reinfections during 2020-2022 in Vojvodina, Serbia: a population-level study

AbstractBackground: Data on the rate and severity of reinfections with SARS-CoV-2 in real-world settings are scarce and the effects of booster vaccination on reinfection risk are unknown. Methods: In a retrospective cohort study, all SARS-CoV-2 laboratory-confirmed residents of Vojvodina, registered in the database of the Institute of Public Health of Vojvodina, between March 6, 2020 …

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Necessity of COVID-19 vaccination in previously infected individuals

The purpose of this study was to evaluate the necessity of COVID-19 vaccination in persons previously infected with SARS-CoV-2. Methods Employees of the Cleveland Clinic Health System working in Ohio on Dec 16, 2020, the day COVID-19 vaccination was started, were included. Any subject who tested positive for SARS-CoV-2 at least 42 days earlier was …

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SARS-CoV-2 infection rates of antibody-positive compared with antibody-negative health-care workers in England: a large, multicentre, prospective cohort study (SIREN)

Increased understanding of whether individuals who have recovered from COVID-19 are protected from future SARS-CoV-2 infection is an urgent requirement. We aimed to investigate whether antibodies against SARS-CoV-2 were associated with a decreased risk of symptomatic and asymptomatic reinfection. MethodsA large, multicentre, prospective cohort study was done, with participants recruited from publicly funded hospitals in …

Continue reading SARS-CoV-2 infection rates of antibody-positive compared with antibody-negative health-care workers in England: a large, multicentre, prospective cohort study (SIREN)