Observational studyDiabetes & metabolic syndrome
Symptomatic post-vaccination SARS-CoV-2 infections in healthcare workers- A multicenter cohort study.
Observational study in Diabetes & metabolic syndrome. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 18 papers, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
18 citing papers in PubMed, 1 synthesis or guideline pooled it, 21 citations in OpenAlex.
- Assessing the Impact of COVID-19 Vaccination Programs on the Reduction of COVID-19 Cases: A Systematic Literature Review.Annals of global health · 2024Pooled it
- Assessing breakthrough infections: Covishield (late schedule) versus Covaxin - A prospective comparative analysis in the general population.Journal of family medicine and primary care · 2025Article
- Revealing COVID-19 breakthrough infection rates among vaccinated individuals at a tertiary care centre in South India.Iranian journal of microbiology · 2025Article
- Post-vaccination SARS-CoV-2 infections among healthcare workers in a tertiary hospital in Ghana.PloS one · 2025Article
- COVID-19 vaccines are effective at preventing symptomatic and severe infection among healthcare workers: A clinical review.Vaccine: X · 2024Review
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- Efficacy and safety of Lianhua Qingwen capsules combined with standard of care in the treatment of adult patients with mild to moderate COVID-19 (FLOSAN): protocol for a randomized, double-blind, international multicenter clinical trial.Journal of thoracic disease · 2023Article
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- Article
- SARS-CoV-2 Breakthrough Infections in Health Care Workers: An Italian Retrospective Cohort Study on Characteristics, Clinical Course and Outcomes.Journal of clinical medicine · 2023Article
- Post-vaccination COVID-19 infection among health care workers in a medical college hospital.Journal of family medicine and primary care · 2022Article
- Demographics and Clinical Characteristics of COVID-19-vaccinated Patients Admitted to ICU: A Multicenter Cohort Study from India (PostCoVac Study-COVID Group).Indian journal of critical care medicine : peer-reviewed, official publication of Indian Society of Critical Care Medicine · 2022Article
- COVID Infections Breakthrough Post-Vaccination: Systematic Review.Journal of pharmacy & bioallied sciences · 2022Article
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- Article
- Global trends in COVID-19.Infectious medicine · 2022Review
- Article
- Post-Vaccination COVID-19 Infection among Health Care Workers: Description, Determinants, and Event-History Analysis.Indian journal of community medicine : official publication of Indian Association of Preventive & Social MedicineArticle
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
11 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
BACKGROUND AND
aimsDuring the COVID-19 vaccination program in India, the healthcare workers were given the first priority. There are concerns regarding the occurrence of breakthrough infections after vaccination. We aimed to investigate the effictiveness of COVID-19 vaccines in preventing and reducing the severity of post-vaccination infections.
methodsThis retrospective test-negative case-control study examined 28342 vaccinated healthcare workers for symptomatic SARS-CoV-2 infections between January 16 to June 15, 2021. They worked at 43 Apollo Group hospitals in 24 Indian cities. These cohorts received either ChAdOx nCOV-19 (Recombinant) or the whole virion inactivated Vero cell vaccines. Various demographic, vaccination related and clinical parameters were evaluated.
resultsSymptomatic symptomatic post-vaccination infections occurred in a small number of vaccinated cohorts (5.07%, p < 0.001), and these were predominantly mild and did not result in hospitalization (p < 0.0001), or death. Both vaccines provided similar protection, with symptomatic infections in 5.11% and 4.58%, following ChAdOx nCOV-19 (Recombinant) and the whole virion inactivated Vero cell vaccines, respectively (p < 0.001). Nursing and Clinical staff and cohorts >50 years contracted more infections (p < 0.001). Two-dose vaccination has significantly lower odds of developing symptomatic infection (0.83, 95%CI - 0.72 to 0.97). Maximum infections occurred during the peak of the second COVID-19 wave from mid-April to May 2021 (p < 0.001). No significant difference existed in the infection between sex, vaccine type, and the number of vaccine doses received (p ≥ 0.05).
conclusionSymptomatic infections occurred in a small percentage of healthcare workers after COVID vaccination. Vaccination protected them from not only infection but also severe disease.
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Registered trials
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