Masks in hospitals made ‘no difference’ to Covid infection rates, study finds

Masks made ‘no discernible difference’ to Covid transmission rates in hospitals, new research suggests.

Infections did not rise as mask mandates were removed in NHS facilities during an Omicron spike.

Experts said today the findings don’t mean face coverings are “worthless.”

But they called for a “rational and proportionate” masking policy in hospitals during future Covid flare-ups because the benefits are “modest at best.”

Governments around the world, including the UK, have mandated the wearing of face coverings in public indoor areas.

Researchers found that the removal of the mask policy in phase two did not cause a “statistically significant change” in the number of hospital-acquired Covid infections. Similarly, they saw “no delayed effect” in the number of Covid infections after the policy was removed, the study added

This was despite a lack of rigorous studies on their effectiveness.

Some hospitals are still urging patients to cover up before entering, though this is no longer required by law.

Researchers at St George’s Hospital in southwest London routinely analyzed collected infection control data over a 40-week period between December 4, 2021 and September 10, 2022.

It marked the time between the first week that Omicron became the dominant Covid variant and the week that universal PCR Covid screening tests were dropped for patients admitted.

During the first phase of the study – December 4, 2021 to June 1, 2022 – all staff and visitors were required to wear masks, both in clinical and non-clinical areas.

In phase two, the mandate was removed.

Instead, mask policy decisions were entrusted to individual hospitals.

High-risk wards, including wards that treat cancer patients and intensive care units, maintained the mask requirement.

Researchers found that the removal of the mask policy in phase two did not cause a “statistically significant change” in the number of hospital-acquired Covid infections.

Similarly, they saw ‘no delayed effect’ in the number of Covid infections after the policy was removed.

This was despite the spread of the virus within the community.

Those in high-risk wards — the control group — who continued to wear masks “also found no immediate or delayed change in infection rate,” the study said.

While masks were initially seen as a measure to prevent viruses, they have become a prominent symbol of the UK’s Covid culture wars.

Officials gave mixed messages about their effectiveness at the start of the pandemic.

Studies have not definitively shown that masks prevented Covid.

In February, one of the most comprehensive meta-analyses of face coverings to date, by the Cochrane Institute, revealed that masks made “little to no difference” to Covid infection or death rates.

As with any observational study, researchers behind the new UK study cautioned that there were potential limitations.

Those in high-risk wards — the control group — who continued to wear masks also “found no immediate or delayed change in infection rate,” the study said.

These include not being able to determine staff infection rates and not assessing compliance with mask-wearing policies.

Lead author Dr Ben Patterson said: “Our study found no evidence that mandatory masking of staff impacts the rate of SARS-CoV-2 infections in hospitals with the Omicron variant.

“That doesn’t mean masks are worthless against Omicron, but their real-world advantage on its own seems modest at best in a healthcare environment.”

Fellow researcher Dr Aodhan Breathnach added: ‘Many hospitals have retained masking at a significant financial and environmental cost and despite the significant communication barrier.

“We hope this empirical evidence can help inform rational and proportionate mask policies in health services.”

The research will be presented later this month at the European Congress of Clinical Microbiology & Infectious Diseases in Copenhagen, Denmark.