Wearing masks in hospitals may have had no impact on COVID-19 transmission during the Omicron wave, a new study reveals. Mask-wearing became part of the essential control measures to stop COVID-19 running riot throughout the pandemic.
But the latest data hints that it may not be as beneficial as people previously thought when fighting against the variant. The team undertook the study in St George’s Hospital, a large hospital in south-west London, during the first ten months of the Omicron wave between December 2021 and September 2022.
In the NHS, a mask mandate for staff was introduced in June 2020, specifying the use of type IIR, fluid-resistant surgical face masks by all staff and visitors. The NHS mask mandate remained in place in clinical areas in hospitals until June 2022.
During the first phase of the study, between 4 December and 1 June, all staff and visitors were required to wear face masks in both clinical and non-clinical areas. In phase two, between 2 June and 10 September, surgical mask-wearing policy was removed for the majority of the hospital but remained for staff in a few high-risk wards.
The team found that in June 2022 the removal of the mask policy was not linked to a significant change in the rate the infection passed throughout the hospital. The infection rate was no higher than when masks were mandatory.
There was also no change in the infection rate during the time when the mask-wearing policy was removed in June 2022 and the end of the study in September 2022. Even the group who continued wearing masks found no immediate or delayed change in infection rate.
Lead author, Dr Ben Patterson, from St George’s University Hospitals NHS Foundation Trust, London, said: “Our study found no evidence that mandatory masking of staff impacts the rate of hospital SARS-CoV-2 infection with the Omicron variant. That doesn’t mean masks are worthless against Omicron, but their real-world benefit in isolation appears to be, at best, modest in a healthcare setting.”
Senior author, Dr Aodhan Breathnach who is also from the hospital, added: “Many hospitals have retained masking at significant financial and environment cost and despite the substantial barrier to communication. We hope this empirical evidence can help inform a rational and proportionate mask policy in health services.”
The study will be presented at the European Congress of Clinical Microbiology & Infectious Diseases 2023, which will take place in Copenhagen between 15 to 18 April.
