Acute Coronavirus Disease (COVID-19) in Vaccinated Frontline Healthcare Workers in India: An Observational Cohort Study

Abstract

Background: Despite vaccination against SARS-CoV-2 (Covid-19), individuals may still develop acute COVID-19 illness. We examined the clinical profile and outcomes of healthcare workers (HCW) in India who developed Covid-19 infection despite being vaccinated. Methods: HCWs in India who developed acute Covid-19 infection despite receiving at least 1 dose of the vaccination were invited to complete an online questionnaire. Out of contacted 2160 HCWs, 316 (14.6%) developed acute Covid-19 infection post- vaccination. We compared their clinical profile based on whether they had received the first or second dose of vaccine, presence or absence of pneumonia and fever at presentation. Results: Of the 316 participants, 50 (15.8%) had developed Covid-19 after receiving only the first dose of the vaccine. Participants who completed both doses of vaccine (n=266) were more likely to be asymptomatic (13.9% vs 2.0%, p=0.016), but clinical outcomes such as hospitalization, need for mechanical ventilation and supplemental oxygen were similar. Participants with pneumonia (n=105, 33.2%) had elevated C-reactive protein (CRP, 25.4±21.2 vs 6.8±8.8 mg/L, p<0.001) compared with those without, and were more likely to require hospitalization (30.5% vs 6.2%, p<0.001) and supplemental oxygen (9.5% vs 0.0%, p<0.001). On multivariable analyses, the completion of both doses of vaccination was protective for the development of fever in Covid-19 illness (adjusted OR 0.33, 95%CI 0.15-0.72), after adjusting for age, prior medical conditions and CRP. Post-vaccination antibody titres to the spike protein were not significantly associated with symptoms or outcomes. Conclusion: Among HCWs vaccinated against Covid-19, a significant proportion (14.6%) developed acute infection. Although similar in terms of clinical outcomes and biochemical markers, participants who completed both doses of vaccination developed milder symptoms. Funding Statement: None. Declaration of Interests: VKS is the current recipient of Senior Clinician Scientist Award from National Medical Research Council, Ministry of Health, Singapore. Other authors have no financial disclosures. ACYC has received grant funding from the National Medical Research Council (NMRC), Singapore and support from the Ministry of Health (MOH), Singapore. Ethics Approval Statement: Ethics approval was obtained from the institutional review board (Zydus Hospitals Ethics Committee (Ref: 2021/05/04) prior to the conduct of this study. Informed consent was obtained from each participant prior to the conduct of the online questionnaire.