Key words:
SARS-CoV-2, healthcare workers, COVID-19 vaccine
INTRODUCTION
The ongoing pandemic of the coronavirus disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had significant impact worldwide. Healthcare workers (HCWs) are considered to be at high risk of exposure to SARS-CoV-2 both in the community and in the workplace and may play a critical role, especially when asymptomatic, in the transmission of the infection within the workplace (both to their patients and co-workers) as well as in the community1.
Preventing SARS-CoV-2 infection among HCWs is critical to ensure safety for both patients and HCWs, to contain the ongoing pandemic, and to maintain a functioning healthcare system.
Many preventive measures have been implemented throughout the pandemic to contain the spread of the SARS-CoV-2 infection in healthcare settings, including universal masking, enhanced hand hygiene and personal protective equipment (PPE) training, symptom screening, and self-isolation of HCWs if symptomatic or in the case of close contact with an infected person. Notably, there has been a paradigm shift in the infection control practices against respiratory infections, which includes widespread testing of patients and HCWs, including asymptomatic individuals2,3.
Universal testing of HCWs enabled the prompt identification of asymptomatic and presymptomatic individuals, determined the effectiveness of control measures, and helped prevent transmission to patients and co-workers1,4,5.
Furthermore, COVID-19 vaccines were developed to overcome the pandemic.
Following the implementation of COVID-19 vaccines, HCWs were among the first prioritised for vaccination in many countries, including Poland. Data from the placebo-controlled randomized phase 3 clinical trial of the Pfizer-BioNTech BNT162b2 vaccine showed 95% efficiency in preventing symptomatic SARS-CoV-2 infection6. Benefits similar to those observed in clinical trials were also observed in real-world conditions7.
There is limited data on the incidence of SARS-CoV-2 infection among HCWs beyond the second wave of the pandemic, and limited data on the incidence of infection before and after the implementation of the vaccination programme, especially for European countries8. So far, most studies performed in Poland were voluntary seroprevalence studies in small cohorts of HCWs, so the representativeness of the results obtained may be limited9,10.
Knowing the factors associated with SARS-CoV-2 infection in HCWs informs preventive measures and improves the protection of HCWs and patients.
To further explore factors associated with SARS-CoV-2 infection, we retrospectively analysed the large real-world testing database obtained between October 20, 2020, and August 31, 2021, at The Children’s Memorial Health Institute (CMHI), a tertiary paediatric hospital in Warsaw. In this setting, 2,332 HCWs participated in the universal screening programme for early identification of the SARS-CoV-2 infection. The aim of the study was to analyse the incidence of new SARS-CoV-2 infections among HCWs (before and after vaccination with BNT162b2) and to explore the demographics and work-related factors associated with SARS-CoV-2 infection. We also attempted to assess the vaccine effectiveness in a real-world setting.
METHODS: