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Risk of COVID-19 infection among frontline healthcare workers during the COVID-19 pandemic
Kundavaram Paul Prabhakar Abhilash1, Mathew Varghese Nellimootil2, Binila Chacko3
1Department of Emergency Medicine, Christian Medical College Vellore, Vellore 632004, Tamil Nādu, India.
Insights
Healthcare workers in high-risk COVID-19 areas faced a greater infection risk before vaccination. Subclinical infections were common among healthcare workers, with similar rates in both high-risk and low-risk settings.
Area of Science:
- Epidemiology
- Infectious Diseases
- Occupational Health
Background:
- Healthcare workers (HCWs) were at high risk of exposure to the SARS-CoV-2 virus during the COVID-19 pandemic.
- Understanding infection risk in different healthcare settings is crucial for implementing effective control measures.
Purpose of the Study:
- To compare the risk of coronavirus disease 2019 (COVID-19) infection among HCWs in high-risk (HR) and low-risk (LR) areas.
- To assess clinical and subclinical infection rates and antibody seroprevalence in HCWs.
Main Methods:
- Prospective study collecting data on confirmed clinical infections and antibody testing (nucleocapsid and spike proteins) from HCWs at five time points.
- HCWs from emergency and intensive care units were categorized as HR, while those from pre-clinical and para-clinical areas were LR.
- Serological analysis included participants with baseline and second-wave samples, with subclinical infection defined by specific antibody detection in asymptomatic individuals.
Main Results:
- Overall clinical infection rates by T5 were similar between HR (32.8%) and LR (26.8%) groups.
- Before vaccination (T3), HCWs in HR areas showed a significantly higher infection rate (21.9%) compared to LR areas (8.8%).
- Subclinical infection rates (HR 34.9%, LR 35.6%) and hospitalization rates were comparable across both groups, with no reported mortality.
Conclusions:
- HCWs in high-risk COVID-19 environments experienced a heightened risk of infection prior to the widespread availability of vaccines.
- Seroprevalence data indicate that subclinical SARS-CoV-2 infections were prevalent among HCWs.
- Findings highlight the importance of protective measures for HCWs, especially in high-exposure settings.
Background:
In the initial stages of the coronavirus disease 2019 (COVID-19) pandemic, healthcare workers (HCWs) who were immunologically naive to COVID-19, were exposed to a highly transmissible virus.
Aim:
To compare infection risk among HCWs in high-risk (HR) and low-risk (LR) areas.
Methods:
Data on reverse transcriptase-polymerase chain reaction confirmed clinical infection and samples for nucleocapsid, and spike protein antibodies were collected at five time-points (T1 to T5) from HCWs in the emergency department and intensive care unit (HR group) and pre-clinical and para-clinical areas (LR). For the sero-study, only participants who provided at least one baseline sample and one during the second wave (T4 or T5) were analysed. Since CovishieldTM elicits only spike protein antibodies, subclinical infection was diagnosed if asymptomatic unvaccinated and CovishieldTM vaccinated individuals tested positive for nucleocapsid antibody.
Results:
Overall, by T5, clinical infection rate was similar in the HR (120/366, 32.8%) and LR (22/82, 26.8%) groups (P = 0.17). However, before vaccination (T3), more HCWs in the HR group developed COVID-19 infection (21.9% vs 8.8%, P = 0.046). In the sero-study group, clinical infection occurred in 31.5% (45/143) and 23.7% (14/59) in the HR and LR groups respectively (P = 0.23). Spike antibody was detected in 140/143 (97.9%) and 56/59 (94.9%) and nucleocapsid antibody was positive in 95/143 (66.4%) and 35/59 (59.3%) in the HR and LR groups respectively (P = 0.34). Subclinical infection rate (HR 34.9%, LR 35.6%, P = 0.37) and hospitalization rate were similar. There was no mortality.
Conclusion:
Before vaccination, HCWs in HR areas had a higher risk of infection. Seroprevalence studies suggest that sub-clinical infection was not uncommon.
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