Throughout the pandemic, masks have been one of the most controversial public health measures in America, revealing sharp partisan divisions over the role of government and individual freedoms.
In May, the US Centers for Disease Control and Prevention (CDC) issued updated guidance, stating that people who have received two full doses of the vaccine do not need to wear masks, even in indoor spaces.
However, that was before the Delta variant appeared.
Three days later, health officials in Los Angeles County, California, followed WHO recommendations, calling on all residents, whether unvaccinated or fully vaccinated, to wear masks in public places, including
Vaccination point at Miami International Airport, USA earlier this month.
Dr. Barbara Ferrer, Los Angeles County health director, said the recommendation was necessary given the increase in cases due to the Delta variant and the high number of unvaccinated people, especially children, people of color and people of color.
About half of Los Angeles County’s population is fully vaccinated and about 60% have received at least one dose.
To control the pandemic, Los Angeles County needs to apply a multi-layered strategy, combining vaccination and restrictive measures, according to Dr. Ferrer.
`We don’t want to go back to the previous blockade or strict regulations. We want to maintain the current roadmap,` Ferrer said.
However, Chicago and New York officials said on June 29 that they have no plans to reimpose mask wearing regulations.
`When the CDC recommended removing masks, the agency certainly did not anticipate a situation where we would need to impose this rule again,` said Angela Rasmussen, a scientist at the Vaccine and Infectious Diseases Foundation at the University of Washington.
But the rapid spread of the Delta variant in the US and many other countries around the world shows that re-imposing epidemic control measures is increasingly necessary.
In Australia, four major cities including Sydney, Darwin, Perth and Brisbane are all blocked.
The Delta strain, which first appeared in India, was quickly present in more than 90 countries. It is considered the `smartest` variation of the original strain that caused the pandemic with the ability to hunt vulnerable people.
Studies in Australia show that the Delta variant can even be easily transmitted when two people `pass` each other without masks in a shopping mall.
Security cameras showed two strangers passing each other while shopping at Bondi Junction Westfield shopping center in Sydney more than two weeks ago, after which both were found to be positive for nCoV.
This has made officials in many Australian states feel worried.
Queensland Premier Annastacia Palaszczuk on June 28 announced the reimposition of mask wearing regulations and other restrictive measures to prevent Delta, when two cases of infection were discovered in this state.
`I really want Queenslanders to wear masks again, especially the south-east,` she said.
The mask mandate applies in indoor spaces such as shopping centres, public transport, hospitals, aged care facilities, churches and other work locations where this is not possible.
New South Wales state officials also started imposing mandatory mask wearing regulations in Sydney, Australia’s largest city, from June 24 and is expected to last a week, to prevent the latest outbreak.
Deserted street due to blockade in Sydney, Australia.
Even Israel, one of the countries with the highest vaccination rates in the world, from the beginning of this week re-established the mask-wearing requirement in indoor spaces and outdoor locations where crowds of people often gather, after
This is not the first time the world has had to confront an infectious variant of nCoV.
But Delta is considered a more terrifying mutation than Alpha.
The reason WHO maintains its recommendation to wear masks is that while vaccines may be effective in preventing severe illness and death, their effectiveness against mild and asymptomatic infections has not been firmly established.
`What we’re saying is that even if you’re fully vaccinated, continue to be vigilant, because it’s very possible that you will become part of the chain of infection. You’re not completely protected,` Bruce Aylward, consultant
Even countries with high vaccination rates are seeing an increase in cases of the Delta variant.
It’s unclear how Delta will affect the US.
The Delta variant can still attack vaccinated people, although the risk is not high, according to Bill Hanage, an epidemiologist at the Harvard T.H. School of Public Health.
Scientists do not recommend that people who have received the full dose of vaccine must always wear masks in indoor spaces, but some believe that this should be based on the actual local epidemic situation.
`Wearing masks in closed spaces should continue after vaccination, until we have all been vaccinated or there is a more effective vaccine against the Delta variant,` Ravindra Gupta, a virologist at the University
In the Canadian province of Saskatchewan, reopening is proceeding according to a roadmap based on vaccination rates.
`This strategy would be better than saying ‘if you’re fully vaccinated, ditch the mask,’` she said.
However, many scientists worry that it will be difficult to reimpose mask wearing regulations and other safety measures in the US.
`It’s very difficult to go back,` David Michaels, an epidemiologist and professor at the George Washington School of Public Health, said of the CDC’s mask recommendation.