Hong Kong: First 'proven' case of COVID-19 reinfection
Medical staff wearing personal protective equipment (PPE) as a precautionary measure against the COVID-19 coronavirus approach Lei Muk Shue care home in Hong Kong on August 23, 2020.
AFP/May James
Hong Kong: First 'proven' case of COVID-19 reinfection
Marlowe Hood (Agence France-Presse) - August 25, 2020 - 7:27am

PARIS, France — Researchers in Hong Kong Monday identified what they said was the first confirmed case worldwide of COVID-19 reinfection, raising questions about the durability of immunity, whether acquired naturally or with a vaccine.

"Our study proves that immunity for COVID infection is not lifelong — in fact, reinfection can occur quite quickly," said Kelvin Kai-Wang To, a microbiologist at Hong Kong University's Faculty of Medicine and lead author of a forthcoming study that details the findings.

"COVID-19 patients should not assume after they recover that they won't get infected again," he told AFP in an interview.

Even people who have shaken off the virus should practice social distancing, wear masks and practise hand washing, he advised.

They should also get tested if suspect symptoms appear.

The case came to light when a 33-year old resident of Hong Kong passed through mandatory screening earlier this month at the Hong Kong airport on his way back from Europe. The so-called PCR swab test was positive.

This came as a surprise because the man had contracted -- and recovered from -- a COVID infection four-and-a-half months earlier, and was assumed to have immunity, especially after such a brief time since the infection.

To find out whether he had suffered a relapse or had been infected anew, To and his team sequenced the two virus strains and compared their genomes, or genetic coding.

The two viral signatures were "completely different", and belonged to different coronavirus lineages, or clades.

The first closely resembled strains collected in March and April, and the second strain matched the virus found in Europe -- where the patient had just been visiting -- in July and August.

"The virus mutates all the time," said To. "It is very unlikely that the patient would have gotten the second virus during the first infection."

The fact that a blood sample -- taken shortly after the positive test at the airport -- showed no antibodies is a further indication that the second virus had not been lingering unnoticed for months. 

"This is certainly stronger evidence of reinfection than some of the previous reports because it uses the genome sequence of the virus to separate the two infections," said Jeffrey Barret, a senior scientific consultant for the COVID-19 Genome Project at the Welcome Sanger Institute, commenting on the study.

Broader implications

Up to now, there have been many cases of suspected re-infection, but none were able to rule out the possibility that the virus has remained latent and reemerged after weeks or months.

But experts differed as to how alarmed the world should be by the new findings, which will be published in the peer-reviewed medical journal Clinical Infectious Diseases.

"This is a worrying finding for two reasons," said David Strain, a clinical senior lecturer at the University of Exeter Medical School.

"It suggests that previous infections are not protective. It also raises the possibility that vaccinations may not provide the hope that we have been waiting for."

If antibodies don't provide lasting protection, "we will need to revert to a strategy of viral near-elimination in order to return to a normal life", he added.

In the same vein, To said that scientists developing vaccines should look not just at the immune response, but at the duration of protection from infection. 

But other researchers suggested that the case uncovered was far more likely to be extremely rare.

"It is to be expected that the virus will naturally mutate over time," said microbiologist Brendan Wren of the London School of Hygiene & Tropical Medicine.

"This is a very rare example of re-infection and it should not negate the global drive to develop COVID-19 vaccines." 

Barrett agreed.

"This may be very rare, and it may be that second infections -- when they do occur -- are not serious," he said.

Indeed, the reinfection of the Hong Kong patient was complete asymptomatic.

But this could also mean that such an outcome may be more common than suspected, said To.

"People don't get tested all the time after they recover, especially if they have no symptoms," he said by phone.

As It Happens
LATEST UPDATE: October 26, 2020 - 10:23pm

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

October 26, 2020 - 10:23pm

The novel coronavirus has killed at least 1,155,301 people since the outbreak emerged in China last December, according to a tally from official sources compiled by AFP at 1100 GMT on Monday.

At least 43,080,500 cases of coronavirus have been registered. Of these, at least 29,194,100 are now considered recovered.

The tallies, using data collected by AFP from national authorities and information from the World Health Organization (WHO), probably reflect only a fraction of the actual number of infections. — AFP

October 26, 2020 - 8:25pm

Spain's Catalonia region said Monday it was studying imposing a lockdown on weekends to fight the spread of the coronavirus, a day after nighttime curfew came into effect across the country.

"It is a scenario which is on the table because it is during the weekend that there are more social interactions," the spokeswoman for the regional government, Meritxell Budo, told Catalan public radio.

Infections have soared in recent days in the wealthy northeastern region, home to around 7.5 million people, as well as the rest of Spain, which last week became the first European Union nation to surpass one million confirmed COVID-19 cases. — AFP

October 26, 2020 - 9:29am

Australian health officials on Monday report no new coronavirus cases or deaths in Victoria state, which has spent months under onerous restrictions after becoming the epicenter of the country's second wave.

It was the first 24-hour period without any new COVID-19 cases reported in the state since the five million residents of Melbourne were locked down after security bungles at quarantine hotels housing returned international travelers sparked a major outbreak in July.

Under the lockdown, people in the city — Australia's second-biggest — have been barred from leaving their homes for non-essential reasons and spent months under an overnight curfew.

Some restrictions were lifted last week, allowing haircuts and golf games to return, but further easing planned for Sunday was delayed to assess thousands of test results after a small outbreak in the city's north. — AFP

October 25, 2020 - 11:08am

The United States saw a record high number of new daily COVID-19 cases for the second day in a row on Saturday, figures from Johns Hopkins University showed, as warnings grew over its spread.

The country reported 88,973 new infections between 8:30 pm Friday and 8:30 pm Saturday, the figures showed, substantially above the previous day's 79,963.

A total of 8,568,625 cases have been reported in the United States with 224,751 deaths, the highest in the world in absolute terms. — AFP

October 24, 2020 - 4:04pm

The Department of Health reports 2,057 additional cases of the coronavirus disease, bringing the national tally to 367,819.

To date, there are 47,773 active cases. The DOH registers 19 new deaths and 442 additional recoveries.

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