SARS-CoV-2 reinfection is rare in individuals with evidence of previous infection in the pre-vaccination era

In a recent study published in pro swan Researchers in the United States (US) evaluated the risks associated with reinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), according to the journal.

Background

As of October 2022, approximately 618 million coronavirus disease 2019 (COVID-19) cases have been identified. The risk of reinfection exists with severe clinical consequences for survivors. In a recent analysis of a US national cohort, researchers observed that seropositivity was associated with a lower risk of future infection at a median 54-day interval.

Positive index Percentage of positives over 90 days after SARS-CoV-2 antibody testing nucleic acid The amplification test (NAAT) finding between index SARS-CoV-2 positive and index negative individuals was 0.1, indicating that previous infection elicited approximately 90% protection against reinfection.

About research

In the present study, researchers investigated the duration of the protective effect of SARS-CoV-2 infection against reinfection. The study population was 144,678,382 individuals collected from US Real Word Data (US RWD) sources vetted by HealthVerity, and health service data acquired between February 2, 2020 and April 30, 2021. Configured.

This dataset combines separate record sources from commercial laboratory databases, pharmacy databases, medical billing databases, hospital charge masters, and outpatient electronic health records (EHRs). This collection includes a SARS-CoV-2 antibody test or Contains information on people who received an index NAAT.

The main findings of the study included identifying a group of people who had been tested for SARS-CoV-2. Individuals were included based on their initial NAAT or SARS-CoV-2 antibody test results. Eligible individuals were required to report 12 months of ongoing closed medical registration, EHR, and billing activity by her index date.

A cohort of SARS-CoV-2-positive patients was identified as a secondary outcome. From February 29, 2020 to December 9, 2020, he recruited individuals whose NAAT or antibody test results for SARS-CoV-2 were first positive.

Individuals were eligible for cohorts based on their initial SARS-CoV-2 antibody or NAAT test results, while SARS-CoV-2-positive individuals fell into the exponential positive cohort. Those with negative results were part of the exponential negative cohort. This cohort included only individuals who had a positive SARS-CoV-2 test result as a secondary outcome.

result

For the primary outcome, nearly 27,070,023 people met the inclusion criteria, of whom 7,501 died and 4,275,540 were excluded from the study. About 22,786,982 people started follow-up 61 days after the index date. There were 2,023,341 SARS-CoV-2 index positive samples and 20,763,641 SARS-CoV-2 index negative samples.

During the follow-up period, 737,742 infections were recorded in the discordant population and 8,869 in the exponential positive cohort. During follow-up, the crude reinfection rate was significantly lower in the index-positive cohort than in the index-negative cohort. During the 375-day follow-up period after the index day, the cumulative incidence of reinfection was approximately 0.85% among those with positive index and 6.2% among those with negative index.

The probability of reinfection was consistent over a median follow-up of 5 months and up to 1 year in patients with a positive index. After adjusting for baseline comorbidities and demographic factors, the probability of reinfection was 87% lower in the index-positive cohort than in the index-negative cohort.

Propensity score concordance analysis yielded estimates of virtually equal coverage and duration of protection. The adjusted risk of infection remained fairly stable throughout the study. These findings indicate that SARS-CoV-2 infection provides strong protection against reinfection for at least 5 months and up to 1 year after recovery.

Over the follow-up period, the crude reinfection rate was approximately 11.75 per 1,000 persons per year, or 12,642 over 1,075,563 per year. People aged 85 years and older were more likely to be reinfected than those aged 18–29 years. They were 2.8 and 1.5 times more likely to report reinfection than non-institutional residents.

Conclusion

Research results have shown that SARS-CoV-2 reinfection is rare among persons with laboratory evidence of previous infection prior to the introduction of the vaccine. Protection against reinfection with SARS-CoV-2 was stable for up to 1 year.

Furthermore, the risk of reinfection was significantly associated with age over 85 years, concomitant immune disorders, and living in a collective care setting. Health care workers had a low risk of reinfection.