A version of this story appeared in the August 21 edition of CNN’s Coronavirus: Fact vs. Fiction newsletter. Sign up here to receive the need-to-know headlines every weekday.

CNN  — 

Masks aren’t a burden, they’re “a patriotic duty.” This was the message last night from Joe Biden, who promised to impose a national mask mandate as part of a beefed-up coronavirus strategy if he wins the US presidency in November.

The benefits of wearing masks are clear. Public health experts have spent months emphasizing that masks are one of the most effective tools to help fight the pandemic, and universal mandates will likely reduce the spread of the airborne virus in indoor and outdoor settings.

But the mere act of donning a piece of cloth has become a hyper-partisan issue in many countries. On Thursday, Brazil’s congress made masks mandatory in closed spaces, like workplaces and places of worship, in defiance of President Jair Bolsonaro, who has often refused to wear one.

Bolsonaro derided Covid-19 from the start, undermining his health ministry’s calls for social distancing with showy, unmasked outings. But even though Brazil has been hit harder than almost any other country – it topped 3.5 million cases yesterday – Bolsonaro is more popular than ever, according to a poll released last week.

As mask mandates harden in Europe, with France requiring coverings to be worn in offices from next month, the continent’s outlier is going in a different direction. Sweden’s chief epidemiologist said this week that he would not recommend face coverings because it could encourage people to take more risks.

“Face masks can be a complement to other things when other things are safely in place. But to start with having face masks and then think you can crowd your buses or your shopping malls – that’s definitely a mistake,” Anders Tegnell told the Financial Times.

The opposite is true, according to a new study published yesterday which found that mask-wearing leads to other protective behaviors, like physical distancing, hand washing and avoiding handshakes.

Meanwhile in China, the latest sign that the country’s epidemic is under control came Thursday, when Beijing’s mask mandate was scrapped – as long as residents do not have “close contact with other people.”

YOU ASKED. WE ANSWERED

Q: Can germicidal ultraviolet lights stop coronavirus transmission?

A: Lamps that use ultraviolet light to kill germs can inactivate coronavirus, but they are not always safe and it’s not clear how good a job they do at killing the virus, the Food and Drug Administration said in a newly-posted advisory.

The FDA said UVC wavelengths are better than UVA and UVB light at destroying viruses, but UVC lamps have their limits.

The effectiveness is unknown “because there is limited published data about the wavelength, dose, and duration of UVC radiation required to inactivate the SARS-CoV-2 virus,” the FDA said in a newly posted statement. Plus the lamps only work in limited circumstances, which don’t mimic many real life situations.

Send your questions here. Are you a health care worker fighting Covid-19? Message us on WhatsApp about the challenges you’re facing: +1 347-322-0415.

WHAT’S IMPORTANT TODAY

Argentinians protest the government's Covid-19 policies in Buenos Aires

Early CDC models had predicted up to 2.4 million US deaths

Early coronavirus models run by the US Centers for Disease Control and Prevention predicted that as many as 2.4 million Americans could be dead from the virus by October, Director Dr. Robert Redfield told the Journal of the American Medical Association Thursday

Now, however, CDC estimates that about 200,000 people will die by the end of the year, Redfield said – significantly fewer than the early models projected. Redfield held up the lower death toll as proof that the nation’s response to the pandemic had worked, though CDC and the Trump administration have been widely criticized for mismanaging the crisis.

Redfield also said that as many as 60 million Americans could have contracted the virus, adding that while cases should start dropping around parts of the country by next week, many in middle America need to stay alert. The US has the biggest number of infections and deaths in the world, with more than 174,000 deaths and over 5.5 million cases, according to Johns Hopkins University.

Europe’s travel windows are slamming shut

The vacation lights are going out all over Europe. Just weeks after many countries opened their borders to travelers within the continent, some are closing again, often at such short notice that people are left scrambling to get home before quarantine orders are put in place, Tamara Hardingham-Gill writes.

Such confusion, often coupled with acrimony and threats of reprisals from countries who feel unfairly added to so-called “red lists” of Covid-19 unsafe destinations, looks set to undermine efforts to salvage Europe’s vital summer tourism economy well before the warm sunshine months have cooled into winter.

The latest casualty is Croatia, which on Thursday was removed from the UK’s safe list. Earlier this week Croatia was also red-listed by Slovenia, its second largest tourist nationality, and Austria. This comes as Belgium adds Malta to its higher risk list, along with Denmark, Finland, Lithuania, Bulgaria and the UK. Norway has added a number of destinations including Greece, Ireland, and Austria.

It’s a far cry from the excitement the news the European Union was throwing open its doors in July brought about.

Ardern schools Trump, but questions grow over New Zealand’s strategy

Prime Minister Jacinda Ardern made a pointed comparison between New Zealand’s coronavirus situation and the epidemic in the United States today, two days after US President Donald Trump said the island nation had a “big outbreak.”

There were 11 new coronavirus cases reported in New Zealand on Friday, Ardern said, adding that the country has “one of the lowest death rates” from the virus, especially compared to the US. “To give you just one example, the United States has 16,563 cases per million, we have 269 per million people,” she said.

Yet there are growing questions over Ardern’s decision to seek the total elimination of Covid-19 from New Zealand by launching some of the world’s toughest restrictions – despite the economic damage that wrought. In light of the country’s fresh outbreak, critics are asking whether the sacrifices were worth it.

Protests across Latin America reflect a toxic cocktail of pandemic and recession

The impact of Covid-19 in Latin America is igniting protests in several countries, as the economic fallout from the pandemic aggravates existing social tensions from the streets of Buenos Aires and Panama City to remote parts of Brazil and Bolivia.

On Monday, at least 25,000 people marched through the Argentine capital Buenos Aires, protesting the government’s continued lockdown, a deepening economic crisis and the government’s plans for judicial reform. Protests were also held in the cities of Cordoba, Mar del Plata and Rosario.

Argentina’s experience echoes across the region, where discontent across a range of issues has coalesced with the pandemic and its economic impact. Hundreds of cafés, bars and restaurants in its capital have been forced to close, pointing to a troubling new chapter for Argentina’s battered economy.

Australia discussing a “No Jab, No Play” vaccine policy

Australia’s Health Minister Greg Hunt says a “No Jab, No Play” coronavirus vaccine policy is being discussed, after Prime Minister Scott Morrison announced that every Australian would be able to receive a potential Covid-19 vaccine for free.

Hunt said he would like to see 95% of the population receive a vaccine once it becomes available, and that a “No Jab, No Play” policy would mean that people would be excluded from certain public events or services unless they had received a vaccination. When asked whether refusal to take one could impact a person’s welfare payments, school attendance or travel, Hunt said it was possible.

Meanwhile in Russia, officials said they would begin post-registration clinical trials for their Covid-19 vaccine candidate next week, amid persistent calls for more data on the jab to be released.

ON OUR RADAR

  • At least 15 US states are now reporting positive cases of Covid-19 at colleges and universities.
  • California wildfires have killed four people, and many are being forced to weigh up the risk of whether to evacuate to shelters and risk catching Covid-19.
  • When it comes to educating the world about coronavirus, public health organizations around the world uniformly exceed recommended reading levels, researchers have found.
  • Another 1.1 million Americans filed initial claims for unemployment benefits on a seasonally adjusted basis last week, dashing economists’ hopes for a second-straight week with fewer than 1 million claims.
  • Costa Rica has joined a small list of countries reopening to US tourists. But there’s a caveat – only Americans from six US states will be allowed to enter.

TOP TIPS

Camping can inspire the most heavenly of thoughts. But in the middle of the pandemic, it inspires a sobering question as well: Is it safe? Here are some things to avoid, according to Dr. Matthew Sims, director of infectious disease research at Beaumont Health in Michigan.

  • Singing around a campfire aerosolizes more virus. If you’re going to sing around a campfire, that’s a potential risk. So if you’re having a moment and just need to burst into song, spread out.
  • Smoke from a campfire. That can make you cough and help spread the virus. If you have a fire, don’t crowd around it.
  • Shared food. This can be a problem when you’re camping, especially if you go with a larger group. If you make a big pot of stew and everyone goes and takes from the same pot and uses the same utensils and ladle, that’s a risk.

TODAY’S PODCAST

“The virus really affects the lungs and people get very, very hypoxic – or their oxygen levels can get really low – and the brain is the one organ that really can’t tolerate that and can get injured very easily.” – Dr. Sherry Chou from the University of Pittsburgh Medical Center

From brain fog to the loss of smell to strokes, we’ve been hearing a lot about the neurological symptoms of Covid-19. CNN’s Chief Medical Correspondent Dr. Sanjay Gupta speaks to Dr. Chou about it in today’s podcast. Listen Now.