The research, led by scientists at Britain’s Cambridge and Greenwich Universities, suggests lockdowns alone will not stop the resurgence of the new SARS-CoV-2 coronavirus, but that even homemade masks can dramatically reduce transmission rates if enough people wear them in public, Reuters reported.

“Our analyses support the immediate and universal adoption of facemasks by the public,” said Richard Stutt, who co-led the study at Cambridge.

He said the findings showed that if widespread mask use were combined with social distancing and some lockdown measures, this could be “an acceptable way of managing the pandemic and re-opening economic activity” long before the development and public availability of an effective vaccine against COVID-19, the respiratory illness caused by the coronavirus.

The study’s findings were published in the “Proceedings of the Royal Society A” scientific journal.

The World Health Organization updated its guidance on Friday to recommend that governments ask everyone to wear fabric face masks in public areas where there is a risk to reduce the spread of the disease.

In this study, researchers linked the dynamics of the spread between people with population-level models to assess the effect on the disease’s reproduction rate, or R-value, of different scenarios of mask adoption combined with periods of lockdown.

The R-value measures the average number of people that one infected person will pass the disease on to. An R-value above one can lead to exponential growth.

The study found that if people wear masks whenever they are in public it is twice as effective at reducing the R-value than if masks are only worn after symptoms appear.

In all scenarios the study looked at, routine facemask use by 50 percent or more of the population reduced COVID-19 spread to an R of less than 1.0, flattening future disease waves and allowing for less stringent lockdowns.

“We have little to lose from the widespread adoption of facemasks, but the gains could be significant,” said Renata Retkute, who co-led the study.

The research by the University of Hong Kong is some of the first to specifically investigate whether masks can stop symptomatic and asymptomatic COVID-19 carriers from infecting others.

Led by Professor Yuen Kwok-yung, one of the world’s top coronavirus experts, the team placed hamsters that were artificially infected with the disease next to healthy animals.

Surgical masks were placed between the two cages with airflow traveling from the infected animals to the healthy ones.

The researchers found non-contact transmission of the virus could be reduced by more than 60 percent when the masks were used.

Two thirds of the healthy hamsters were infected within a week if no masks were applied.

The infection rate plunged to just over 15 percent when surgical masks were put on the cage of the infected animals and by about 35 percent when placed on the cage with the healthy hamsters.

Those that did become infected were also found to have less of the virus within their bodies than those infected without a mask.

“It’s very clear that the effect of masking the infected, especially when they are asymptomatic — or symptomatic — it’s much more important than anything else,” Yuen told reporters.

“It also explained why universal masking is important because we now have known that a large number of those infected have no symptom.”

Yuen was one of the microbiologists who discovered the SARS virus — a predecessor of the current coronavirus — when it emerged in 2003, killing some 300 people in Hong Kong.

Armed with knowledge from that fight, he advised Hong Kongers early in the current pandemic to adopt universal masking, something embraced by the city’s residents.

At the time the World Health Organisation and many other foreign health authorities dismissed using masks widely among the public, saying they should instead go to frontline medical workers.

Four months after its first COVID-19 case was detected, Hong Kong has largely managed to contain the disease with just over 1,000 infections and four deaths.

Experts have credited widespread mask use as well as efficient testing, tracing and treatment in the city of 7.5 million for the relatively low numbers.