There is only "weak evidence" that advanced masks protect health workers better than surgical masks during the pandemic, a Covid inquiry has heard.

Professor Susan Hopkins, chief medical adviser to the UK Health and Safety Agency (UKHSA), said that in real life, respirator masks, known as FFP3s, may not perform any better than thin surgical masks.

Wearing tight-fitting FFP3s could cause "serious injuries" including blisters and difficulty breathing, she said.

"If there's strong evidence that FFP3 does protect people, and we see a significant reduction (infections), then they would be recommended," she said.

Not all scientists agree on this controversial issue.

British Broadcasting Corporation Previously reported research This seems to indicate that wearing advanced masks in hospital wards has significant real-world benefits.

In the first two years of the pandemic, groups representing doctors, nurses and other health workers repeatedly called for urgent improvements in personal protective equipment (PPE), including wider use of respirators.

The FFP3 is a tight-fitting mask with a built-in air filter designed to block tiny aerosol particles that can carry viruses.

Before use, each wearer must undergo a fit test to ensure the mask seals properly to the face.

For much of the pandemic, national guidance across the UK has said that except in critical care or in a small number of medical situations, healthcare workers should wear basic surgical masks rather than FFP3 masks.

The decision was harshly criticized by some staff at doctors' union BMA, who described it as a "matter of life and death".

National mask guidance from April 2020 was developed by experts from IPC (Infection Prevention and Control) groups across the UK.

Its members include representatives from the NHS, government departments and health agencies, including Public Health England (PHE), which was reorganized in 2021 as part of a reorganization ordered by then health secretary Matt Hancock Replaced by UKHSA.

The inquiry is part of the minutes of an IPC Cell meeting on December 22, 2020, just after the detection of the new Alpha variant of Covid, which appeared to be showing disagreement over the use of higher-grade FFP3 masks.

The record quotes Dr Colin Brown, UKHSA's deputy director of clinical and emerging infections at the time as Public Health England (PHE), as saying: "Our understanding of aerosol transmission has changed. Take precautions and move to using FFP3 masks (in all healthcare settings) should inform us while we await evidence."

However, the wider IPC group decided at that time that there was no need to upgrade the guidance, and NHS trusts were told to continue to provide staff with standard surgical masks in almost all settings outside intensive care units.

It was not until January 2022 that the advice changed, saying FFP3 respirators should be provided to "all relevant personnel" based on risk assessments.

By then, the World Health Organization and other health agencies had recognized that the coronavirus could spread more than 6.5 feet (2 m) through tiny particles in the air, something officials said was impossible at the start of the pandemic.

Professor Hopkins, who was PHE's chief coronavirus adviser before moving to UKHSA, told the inquiry that FFP3 masks provided a high degree of protection in laboratory studies, but the benefits in the real world were less clear.

"We have repeatedly studied and are still studying that there is insufficient evidence to suggest that FFP3 provides better protection than a fluid-resistant surgical mask," she said.

"The risk from March 2020 is that we never asked people to wear FFP3 masks for an extended period of time.

"We're seeing ulcers on their faces, difficulty breathing, difficulty staying hydrated."

Professor Hopkins said the UK was about to enter a "really challenging period" of the coronavirus pandemic when asked about the December 2020 IP Cell meeting minutes, which suggested Public Health England was behind the scenes Wider use of masks in health care. The third wave of the virus.

She said: "Public Health England raises and expresses different views and this is an example of (we) not engaging in groupthink."

The Covid inquiry is currently gathering evidence on the impact on the NHS and healthcare systems in all four countries of the UK.

More than 50 witnesses are expected to appear in the third part, or "module," which will run until the end of November.