Analysis of COVID-19 reinfection and its influencing factors among primary healthcare workers in Jiangsu Province: a study based on the omicron variant epidemic.

Objectives: Since the global outbreak of SARS-CoV-2 in 2019, COVID-19 reinfection has become an increasing concern, particularly during the spread of the Omicron variant. Despite numerous international studies on COVID-19 reinfection, research focusing on healthcare workers, particularly those in primary care settings in mainland China, remains limited. This study aims to evaluate COVID-19 reinfection rates among primary healthcare workers (PHWs) in Jiangsu Province and to explore potential risk factors contributing to reinfection. Methods: This study utilized a combination of online questionnaires and on-site surveys to conduct two waves of investigation targeting PHWs after epidemic control policy adjustment in Jiangsu Province. Differences between the infection at the baseline visit and re-infection at the follow-up visit were analyzed, and multivariate logistic regression was used to assess the factors influencing reinfection. Results: A total of 5,541 PHWs were included in the study. At the baseline visit, the initial infection rate was 85.85% [95% confidence interval (CI): 84.93-86.77%], and the self-reported reinfection rate was 40.05% (95% CI: 38.65-41.44%). After adjustment, the reinfection rate was 29.41% (95% CI: 28.12-30.71%). The median reinfection interval between the two infections was 146 days (Interquartile range: 129-164 days). Logistic regression model revealed that female sex [odds ratio (OR) = 1.376, 95% CI: 1.190-1.592], history of fever clinic work (OR = 1.179, 95% CI: 1.045-1.330), working over 8 h per day (OR = 1.178, 95% CI: 1.040-1.336), being a nurse (OR = 1.201, 95% CI: 1.029-1.402), and a "less meat, more vegetables" diet (OR = 1.206, 95% CI: 1.020-1.426) were significant risk factors for reinfection. Additionally, regular physical exercise was found to be a protective factor (OR = 0.861, 95% CI: 0.754-0.983). Conclusion: COVID-19 reinfection rates were relatively high among PHWs in Jiangsu Province, particularly among women, nurses, those with fever clinic experience and working over 8 h per day. This study offers valuable insights for the prevention of COVID-19 reinfection and the development of protection strategies for PHWs. It is recommended that more targeted protective measures be implemented for high-risk groups, including appropriate work arrangements, regular health monitoring, and the promotion of healthy lifestyle habits.