A version of this story appeared in the August 26 edition of CNN’s Coronavirus: Fact vs. Fiction newsletter. Sign up here to receive the need-to-know headlines every weekday.

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The US Centers for Disease Control and Prevention has changed its Covid-19 testing guidelines, prompting confusion and concern from some doctors.

The agency no longer recommends testing for most people without symptoms, even if they’ve been in close contact with someone known to have the virus. Previously, the CDC said viral testing was appropriate for people with recent or suspected exposure, even if they were asymptomatic.

Asymptomatic carriers play a major role in spreading Covid-19. Testing and isolating these silent emitters are vital to providing a pathway out of the outbreak. Even the world’s fastest man, Usain Bolt, tested positive this week despite not showing any symptoms.

CDC’s modified guidelines say people who were within six feet of a Covid-19 positive individual for at least 15 minutes, and are not showing symptoms, “do not necessarily need a test.”

The change troubled health experts in America, which has been besieged by coronavirus testing failures and shortages. Asymptomatic testing “is key to contact tracing, especially given that up to 50% of all transmission is due to people who do not have symptoms,” Dr. Leana Wen, a public health professor at George Washington University, told CNN. “One wonders why these guidelines were changed – is it to justify continued [a] deficit of testing?”

New Covid-19 cases may be falling in many US states, but some officials across the heartland are reporting a worrying rise in numbers. Kansas Gov. Laura Kelly said the state’s infection rate “continues an alarming trend in the wrong direction.” In Kentucky, Gov. Andy Beshear warned cases could spike again as the state reported more deaths last week than “in any other week battling the virus.”

YOU ASKED. WE ANSWERED

Q: Should I send my children back to school?

A: Children can be more reluctant because they’re more sensitive to new things than adults are, said Christopher Willard, a psychiatry lecturer at Harvard Medical School.

Walmart provided its ambassadors and management with talking points for handling incidents with anti-maskers. Managers were instructed to ask customers if they’d like a complimentary mask, and if they refuse, the talking points advise letting them to continue shopping.

This week the CDC outlined a number of steps businesses can take, which include conflict-resolution training for their workers, installing security systems and identifying designated safe areas in stores employees can go to if they feel in danger. One of the agency’s main suggestions: “Don’t argue with a customer if they make threats or become violent.”

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

Melania Trump offers Covid-19 sympathies as polling shows deaths are a partisan issue

First Lady Melania Trump struck a markedly different tone from many of the speakers at this week’s Republican National Convention when she offered condolences to the Americans touched by the coronavirus pandemic.

“My deepest sympathy goes out to everyone who has lost a loved one and my prayers are with those who are ill or suffering. I know many people are anxious and some feel helpless. I want you to know you are not alone,” she told the nation in an address from the White House Rose Garden last night.

But pictures of her audience are the latest sign that the Trump administration is not taking things as seriously as it could be. Attendees in the Rose Garden did not observe social distancing. Few wore masks and some guests were not tested for Covid-19, according to a person who attended the speech. The First Lady’s chief of staff told CNN that the people seated in the rows near the President and Vice President were tested, as was anyone who came into close contact with them.

That kind of apathy towards the public health crisis is evident among many Republicans. A CBS/YouGov poll found that 57% of registered Republican voters say the Covid-19 death toll is “acceptable,” while only 10% of Democrats and 33% of independents would phrase it that way. What explains the discrepancy? Partisanship, mostly, Chris Cillizza writes.

One US business conference linked to 20,000 Covid-19 cases

One superspreading event may be connected to about 20,000 coronavirus cases in the Boston area, a researcher said on Tuesday. That event, a biotech conference attended by 200 people in late February, is now well known as a source of Covid-19 spread very early on in the pandemic.

The new study – which has not yet been peer-reviewed – claims to provide “direct evidence” that superspreading can profoundly alter the course of an epidemic, Jacqueline Howard and Carma Hassan write.

More recently, a Covid-19 outbreak sparked at a wedding in Maine has been linked to cases at a nursing home and a jail. And now dozens of cases across several states are being linked back to a motorcycle rally in South Dakota in early August – which experts warned at the time could become a super-spreader event.

Coronavirus disrupting polio vaccination efforts in Africa

Africa reached a milestone on Tuesday when the World Health Organization declared polio had been eradicated from the region. But vaccination will have to continue to keep the virus from coming back – and the coronavirus is disrupting that effort, the WHO’s regional director on Africa said yesterday.

The oral polio vaccine uses a weakened but not completely inactive strain of virus that can mutate into a pathogenic form if it circulates among incompletely immunized people. Vaccination must continue to keep this strain from causing outbreaks, the WHO said. The Covid-19 pandemic means that some immunization campaigns are being postponed in 16 countries that are dealing with this type of polio.

Countries strengthen their face mask mandates in Europe

Countries and regions in Europe are strengthening their face mask rules as kids start the new academic year. The UK government made yet another U-turn on its coronavirus response on Wednesday, mandating that secondary school children in regions under lockdown will now be required to wear masks in communal areas.

The Czech Republic has made face masks mandatory again, but not just in schools. On September 1 – the same day schools reopen – face masks will have to be worn in a number of settings, including health and social care facilities and public transport. Face masks will only be required in schools if the epidemiological situation deteriorates. The government said the national mask mandate was directly related to the reopening of classrooms.

Spain’s capital Madrid also announced Tuesday that face coverings would be mandatory at schools for children over the age of six. Similar rules were announced in the region of Catalonia for school children aged 12 and up.

Latin American countries brace for more infections

Argentina reported a record number of cases for a second day in a row on Tuesday, the same day Mexico said more than 1,300 healthcare workers had died from the virus since the pandemic began.

Mexico is now preparing for marked rise in new daily cases after it widened the criteria for detecting Covid-19 from suspected cases.

In Brazil, the virus continues to spread through its political class. Brazilian President Jair Bolsonaro’s eldest son, Flávio Bolsonaro, tested positive for Covid-19 on Tuesday. The development came as Butantan, one of Brazil’s vaccine research centers and producers, said it expects to have 45 million doses of the experimental Chinese Covid-19 vaccine CoronaVac by the end of December.

ON OUR RADAR

  • Researchers in Leipzig, Germany staged a 1,500-person experimental indoor concert on Saturday to better understand how Covid-19 spreads at big, busy events – and how to prevent it.
  • With mass layoffs at US air carriers expected this fall, thousands of pilots are learning how to fly drones.
  • Two first grade teachers in Florida transformed their students’ desks into little Jeeps so that their students felt comfortable while following social distancing guidelines.
  • Police in Springfield, Massachusetts are looking for a man who gave several Walmart shoppers a “Covid hug.”
  • Japanese airline ANA is testing a new hands-free bathroom door that passengers can open with their elbow or forearm.
  • New Zealand’s Prime Minister Jacinda Ardern extended Auckland’s lockdown to the end of this week after the country reported eight new cases on Monday.

TOP TIPS

The pandemic is threatening how we benefit from wider friendships. Here’s how to fix that:

“Recent research has observed a decrease in loneliness following the pandemic — this may reflect the fact that many people are now clinging to their closest ties. … Although physical contact is now much more limited, many of these other (virtual) bonding opportunities are just as abundant as ever,” Andrea Courtney, a postdoctoral research fellow in psychology at Stanford University in California, told CNN.

To keep up relationships, emotional closeness and trust during this time, stay in virtual touch as much as possible. And remind your loved ones, “I’m still here and thinking of you.”

TODAY’S PODCAST

They’re on the edge of the abyss.” – CNN International Correspondent Ben Wedeman

Public health experts estimate the United States needs 100,000 to 300,000 contact tracers for Covid-19. But we’re still far from that number. CNN’s Chief Medical Correspondent Dr. Sanjay Gupta looks into the status of contact tracing in today’s podcast. Listen Now.