Toronto, Nov 30 (IANS): Surgical masks are not inferior to N95 masks for stopping the spread of Covid-19 among health-care providers at hospitals, according to researchers.

According to a study led by researchers at McMaster University in Canada who tracked 1,009 health-care workers at 29 sites in Canada, Egypt, Israel and Pakistan between May 2020 and March 2022, surgical masks are indeed effective against Covid.

"The surgical masks were not statistically less effective than N95s in preventing infections in health-care providers looking after patients with Covid-19," said lead author Mark Loeb, professor of McMaster's Department of Pathology and Molecular Medicine and a Hamilton infectious disease physician.

The major thrust of this study is that there have been no other rigorous comparisons of surgical masks to N95 respirators.

"This was also the only randomised clinical trial - offering the highest standards of evidence - relating to this question throughout the pandemic," said the study published in the journal Annals of Internal Medicine.

Loeb said a systematic review of four previous randomized controlled trials on masks done between 1990 and March 2020 shows the use of surgical masks did not increase viral respiratory infection or clinical respiratory illness.

There have been conflicting recommendations on the use of N95 masks during the pandemic.

The US Centers for Disease Control and Prevention (CDC) recommended N95s for routine care of patients with Covid-19, while the World Health Organization (WHO) and Canadian Public Health Agency recommended either surgical masks or N95 respirators.

The study comes as low and middle-income countries are still struggling to procure N95 masks due to their high cost.

Loeb said many of these same countries faced an acute shortage of N95s throughout the pandemic.