'Test-&-trace' crucial but won't beat coronavirus alone: study
A man undergoes a swab test for coronavirus at a drive-through testing site of the Santa Maria della Pieta hospital in Rome on August 18, 2020. On August 16, Italy suspended its discos and ordered the mandatory wearing of masks from 6:00pm (1600 GMT) to 6:00am to clamp down on the spread of infection among young people, less than a month before the restart of school.
AFP/Tiziana FABI
'Test-&-trace' crucial but won't beat coronavirus alone: study
Marlowe Hood (Agence France-Presse) - August 19, 2020 - 7:51am

PARIS, France — Testing for COVID-19 and tracing the prior contacts of those found to be infected are crucial measures for slowing the disease's spread, but inadequate unless combined with other measures, researchers said Wednesday.

By itself, the test-and-trace approach can reduce the virus' reproduction rate, or R number, by 26 percent, they reported in The Lancet Infectious Diseases, using mathematical models to examine data from previously published studies.

The reproduction rate measures the number of people in a population, on average, infected by each person carrying the virus.

Anything above "1" means the disease is continuing to expand; below that threshold, it will eventually peter out.

Some countries that brought the spread of COVID-19 under control but are now struggling to prevent a resurgence have R numbers well above 1. 

In France, for example, it hovered at about 1.33 during the first week of August, according to national health authorities.

But the new finding comes with a caveat, said lead author Nicholas Grassly, a professor at Imperial College's School of Public Health.

"Our results show that test and trace can help reduce the R number but needs to be carried out effectively and quickly to do so," he said in a statement. 

Concretely, that means immediate testing with the onset of symptoms and results within 24 hours; the quarantine of contacts, also within 24 hours; and the identification of 80 percent of cases and contacts.

Very few countries -- notably South Korea, Taiwan and Germany -- have come close to staying within these guidelines, and most are still falling well short.

In France, for example, it generally take days to get an appointment for a so-called PCR nasal test, and on average 3.5 days for a result, according to official figures.

Herd immunity not close

In the United States and the UK, delays can be even longer.

Even if nations do adhere to these guidelines, it will still not be enough to bring the infection rate down sufficiently by itself, the new study concludes.

"Test and trace alone won't be enough to control transmission in most communities, and other measures alongside will be needed to bring the R number below 1," said Grassly.

Weekly screening of high-risk groups such as health and social-care workers -- regardless of whether they have symptoms or not -- can reduce transmission by an additional 23 percent, his team found.

Experts are still unsure as to what percentage of a population must be immune -- a threshold known as "herd immunity" -- to prevent the virus from continuing to spread. 

Estimates range from below 50 to 70 percent.

It is possible that some of the hardest hit regions -- New York City, northern Italy -- may be close to these levels, but at a national scale the numbers are still far lower, probably barely in double digits.

WHO emergencies director Michael Ryan said Tuesday that the planet was "nowhere close to the levels of immunity required to stop this disease".

People should "not live in hope of herd immunity being our salvation. Right now, that is not a solution," he added.

A vaccine, of course, would also provide immunity, but is unlikely to be available until next year.

Currently, only people who have fought off COVID-19 and survived have some degree of immunity, though it remains unclear how robust it is and how long it lasts.

It is also unclear the extent to which people with mild or asymptomatic cases have immunity at all. 

The novel coronavirus has killed nearly 775,000 people and infected almost 22 million since the outbreak emerged in China last December, according to a tally from official sources compiled by AFP.  

As It Happens
LATEST UPDATE: November 30, 2020 - 12:49pm

Follow this page for updates on a mysterious pneumonia outbreak that has struck dozens of people in China.

November 30, 2020 - 12:49pm

America should prepare for a "surge upon a surge" in coronavirus cases as millions of travelers return home after the Thanksgiving holiday, top US scientist Anthony Fauci warned Sunday.

The United States is the world's worst-affected country, with 266,831 COVID-19 deaths, and US President Donald Trump's administration has issued conflicting messages on mask-wearing, travel and the danger posed by the virus.

"There almost certainly is going to be an uptick because of what has happened with the travel," Fauci told CNN's "State of the Union." 

Travel surrounding Thursday's Thanksgiving holiday made this the busiest week in US airports since the pandemic began.

"We may see a surge upon a surge" in two or three weeks, Fauci added. "We don't want to frighten people, but that's the reality." — AFP

November 29, 2020 - 4:10pm

The Department of Health reports an additional 2,076 COVID-19 cases in the Philippines, pushing the national caseload to 429,864.

The DOH also records 10,579 new recoveries, bringing the total of recovered patients to 398,624. With 40 new reported deaths, the country's death toll is now at 8,373.

With the latest figures, total active cases in the country stand at 22,867.

November 29, 2020 - 3:02pm

Around 9,000 runners — some wearing face masks — took part in the Shanghai International Marathon Sunday, Chinese media said, a rare mass event in a year when coronavirus laid waste to most such sport.

Prior to the race officials touted it as an opportunity to show how China — where the virus emerged late last year before unleashing a pandemic — is moving ahead despite the continuing global health crisis.

The prestigious New York, Berlin, Boston and Chicago marathons all fell victim to coronavirus this year, while London and Tokyo were open only to elite runners.

Bucking that trend, the Shanghai marathon went ahead under sunny skies following several days of rain, and with virus prevention measures in place to thwart infections. — AFP

November 28, 2020 - 5:18pm

More than 400,000 deaths from the novel coronavirus have been registered in Europe, according to an AFP tally compiled from official sources around 0800 GMT Saturday.

The second-worst hit global region after Latin America and the Caribbean, 400,649 people have died of Covid-19 in Europe among 17,606,370 confirmed cases. Of these, 36,147 occurred in the past week alone -- the continent's worst seven-day total since the pandemic began.

Britain accounted for almost two-thirds of the European deaths at 57,551 from almost 1.6 million infections, followed by Italy with 53,677 deaths and 1.5 million infections, France (51,914 deaths, 2.2 million cases), Spain (44,668 deaths, 1.6 million cases) and Russia (39,068 deaths, 2.2 million cases). — AFP

November 28, 2020 - 4:04pm

The Department of Health confirms 1,893 new cases of the coronavirus disease. Total cases now at 427,797.

Out of the confirmed cases, 31,402 are registered active. There are 79 additional fatalities and 474 new recoveries.

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