ArticlePloS one2022
Protective effect conferred by prior infection and vaccination on COVID-19 in a healthcare worker cohort in South India.
Article in PloS one, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 16 papers, 1 of them a synthesis that pooled it.
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Who cites it
16 citing papers in PubMed, 1 synthesis or guideline pooled it, 21 citations in OpenAlex.
- COVID-19 vaccines reduce the risk of SARS-CoV-2 reinfection and hospitalization: Meta-analysis.Frontiers in medicine · 2022Pooled it
- Article
- Revealing COVID-19 breakthrough infection rates among vaccinated individuals at a tertiary care centre in South India.Iranian journal of microbiology · 2025Article
- COVID-19 vaccines are effective at preventing symptomatic and severe infection among healthcare workers: A clinical review.Vaccine: X · 2024Review
- Review
- Effects of Severe Acute Respiratory Syndrome Coronavirus Vaccination on Reinfection: A Community-Based Retrospective Cohort Study.Vaccines · 2023Article
- Evidence of leaky protection following COVID-19 vaccination and SARS-CoV-2 infection in an incarcerated population.Nature communications · 2023Article
- Evolution of seroprevalence to SARS-CoV-2 in blood donors in Sarajevo Canton, Federation of Bosnia and Herzegovina: Cross-sectional and longitudinal studies.Influenza and other respiratory viruses · 2023Article
- Effectiveness of Covid-19 vaccines against symptomatic and asymptomatic SARS-CoV-2 infections in an urgent care setting.Vaccine · 2023Article
- Impact of COVID-19 Vaccination on Seroprevalence of SARS-CoV-2 among the Health Care Workers in a Tertiary Care Centre, South India.Vaccines · 2022Article
- COVID-19 and plasma cells: Is there long-lived protection?Immunological reviews · 2022Review
- Protection against SARS-CoV-2 after Covid-19 Vaccination and Previous Infection.The New England journal of medicine · 2022Article
- Covid-19: virology, variants, and vaccines.BMJ medicine · 2022Review
- SARS-CoV-2 variants: Impact on biological and clinical outcome.Frontiers in medicine · 2022Review
- Fully understanding the efficacy profile of the COVID-19 vaccination and its associated factors in multiple real-world settings.Frontiers in immunology · 2022Review
- Article
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Authors and funding
6 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundThe emergence of newer variants with the immune escape potential raises concerns about breakthroughs and re-infections resulting in future waves of infection. We examined the protective effect of prior COVID-19 disease and vaccination on infection rates among a cohort of healthcare workers (HCW) in South India during the second wave driven mainly by the delta variant. METHODS AND
findingsSymptomatic HCWs were routinely tested by RT-PCR as per institutional policy. Vaccination was offered to all HCWs in late January, and the details were documented. We set up a non-concurrent cohort to document infection rates and estimated protective efficacy of prior infection and vaccination between 16th Apr to 31st May 2021, using a Cox proportional hazards model with time-varying covariates adjusting for daily incidence. Between June 2020 and May 2021, 2735 (23.9%) of 11,405 HCWs were infected, with 1412, including 32 re-infections, reported during the second wave. 6863 HCWs received two doses of vaccine and 1905 one dose. The protective efficacy of prior infection against symptomatic infection was 86.0% (95% CI 76.7%-91.6%). Vaccination combined with prior infection provided 91.1% (95% CI 84.1%-94.9%) efficacy. In the absence of prior infection, vaccine efficacy against symptomatic infection during the second wave was 31.8% (95% CI 23.5%- 39.1%).
conclusionsPrior infection provided substantial protection against symptomatic re-infection and severe disease during a delta variant driven second wave in a cohort of health care workers.
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