Clinico-epidemiological profile and outcome of infected health care workers during the three consecutive waves of COVID-19 pandemic: a longitudinal cohort study

Background: Health care workers are considered as high-risk population, who deal with many unknown, undiagnosed, and subclinical infectious diseases in their daily life. Currently, the COVID-19 pandemic posed as an add-on burden for these frontline workers in all aspects. Although, many adverse physical and mental effects of pandemic among health care workers (HCWs) were discussed worldwide, a long-term study for delayed complications needed to be explored.

Aim: The study evaluates and compares three waves of the pandemic in various aspects such as the incidence, prevalence, severity, risk factors, and variations in the pattern of COVID-19 infection, impact of vaccination, and post-infection complications among the HCWs.

Methodology: A longitudinal observational study was carried out over a period of 2 years and another 6 months for follow-up. The study included all HCWs who tested positive in any one wave of COVID-19 pandemic with any one of the confirmed COVID-19 test. Each COVID-19-affected HCW was followed up through telephone calls and direct interviews conducted at the study site. Admission details and other background details of the study population were collected from the hospital records.

Results: A total of 968 HCWs were COVID-19 positive in any of the three waves, and highest incidence (53.00%) was caused by the Omicron variant. High severity and hospitalization was observed in the first wave (no vaccination) and fully immunized personnel were found to be out of danger of being hospitalized during all succeeding waves (chi-square value: 87.04, p < 0.05). Predictors such as female gender, occupational exposure, and comorbid status were identified as possible risk factors for infection. A total of 70 HCWs reported with 104 complications, of which chronic diseases such as new onset of diabetes (n = 3), cardiovascular events (n = 8), worsening of preexisting comorbidities (n = 8), etc. were found out.

Conclusions: This study proves the benefit of being immunized rather than the risk of being infected. This study documents that immunization impacted complication and hospitalization rates of COVID-19 infection. This evidence may help in tackling vaccine hesitancy across the nations.