COVID Vaccination Prevented Infection, Reduced Absence for Health Care Workers During Second Wave, Studies Find

The rapid rollout of COVID-19 vaccines from December 2020 averted infection and reduced absence related to the virus for patient-facing NHS hospital workers in England during the second wave of the pandemic, according to research published in The BMJ.

Another study found that both the Pfizer BioNTech and Oxford-AstraZeneca COVID-19 vaccines provided strong protection against COVID-19-related hospital attendance and admissions for health care workers. Researchers hope these findings can be used to guide further prevention and control measures.

The study authors compared the efficacy of the Pfizer BioNTech and the Oxford-AstraZeneca COVID-19 vaccines against infection in health care and social care workers in England using data from the OpenSAFELY research platform. The 317,341 participants were vaccinated between January 4, 2021, and February 28, 2021.

The results showed strong protection from both vaccines with no substantial differences between the 2 vaccines in rates of infection or COVID-19-related hospital attendance and admission. These findings provide insight into SARS-CoV-2 infection in health care and social care workers.

Health care workers were among the first groups eligible to receive COVID-19 vaccination from December 2020. Though first-line health care workers were prioritized during rollout, coverage varied among health care worker groups, which may have led to disparities in exposure and protection across the workforce.

In the other study, researchers investigated the rate of, risk factors for, and impact of vaccines on SARS-CoV-2 infection in susceptible hospital health care workers during England’s second wave from September 1, 2020, through April 30, 2021. They analyzed data from the SARS-CoV-2 Immunity and Reinfection Evaluation (SIREN) study on 18,283 clinical, support, and administrative staff with no evidence of previous infection who were recruited from 105 NHS hospital trusts in England.

Participants completed a survey about their demographic, household, and occupational characteristics at enrollment. Subsequent questionnaires were completed every 2 weeks, including information on whether they had been vaccinated.

PCR tests were taken every 2 weeks and antibody tests every month throughout the study period. Researchers found that 13% (2353) of participants became infected during the second wave, after accounting for demographic, household, and occupational factors.

Infections peaked in late December 2020 and then decreased from January 2021, in line with the rapid vaccination coverage among health care workers and a national lockdown, according to the study authors.

Multiple factors were found to increase the likelihood of infection in the second wave: being under 25 years of age, living in a household of 5 or more people, having frequent exposure to patients with COVID-19, working in an emergency department or inpatient ward setting, and being a health care assistant.

Time to first vaccination was found to be strongly associated with infection. Each day without vaccination increased a participant’s odds of infection by 2%.

Mathematical Model simulations indicated that an additional 10% of all patient-facing hospital health care workers would have been infected were it not for the rapid vaccination coverage provided through the rollout. Additionally, staff absence due to COVID-19 could have been 69% higher without the rollout, according to the study.

The authors noted limitations of the study. Given the observational nature of the study, cause could not be established. Another limitation was the lack of detail needed to explore variations in hospital infection prevention and control policies.

However, the authors assert that SIREN is a large study well positioned to explore the incidence of SARS-CoV-2 infection in the hospital workforce.

This study “reinforces the importance of vaccination among health care workers during a significant wave of the SARS-CoV-2 pandemic in England,” they wrote.

“Greater understanding of transmission dynamics among health care workers, particularly according to role and setting, will support NHS trusts in protecting their workforce and patients from SARS-CoV-2 infection and potentially other seasonal winter viruses,” the authors concluded.

Reference

COVID vaccines averted infection in 10% of patient-facing healthcare staff during second wave. EurekAlert. News Release. July 20, 2022. Accessed July 22, 2022. https://www.eurekalert.org/news-releases/959208