Introduction and study aim: Very few studies have demonstrated the effects of a booster dose, and almost none after the emergence of the Omicron sub-lineage variants. The policy of giving a booster dose to healthcare workers started with the eminent third wave. The aim was to calculate the breakthrough infection rate among healthcare workers after receiving a booster dose during the third wave of the pandemic in India.
Patients and Methods: The authors conducted the study in a teaching hospital in India. The study defined breakthrough infection as a positive report on day seven or later. The study collected the list of healthcare workers who took booster doses from 10 January to 15 February 2022 and tested symptomatic for SARS-CoV-2. From 16 January 2022, we telephonically contacted all positive persons and obtained their history. Similarly, the authors collected daily information about positive healthcare workers from all wards and outpatient departments.
Results: Forty-eight healthcare workers had a breakthrough infection among 803 who took booster doses; however, 43 telephonically responded. The mean interval between booster dose and positivity was 13.93 (S.D.=6.10) days. The breakthrough infection rate was 194.51/per 100,000 person-days. The most affected profession was doctors (66.44%). The participants perceived that a history of contact (apart from their COVID-19 ward duty) was the commonest reason for contracting the infection. About one-fourth of them had some comorbidity. The commonest comorbidity was hypertension. All had mild symptoms.
Conclusion: Among healthcare workers, breakthrough infections were low during peak transmission.