Hong Kong researchers report first documented coronavirus re-infection

Findings indicate disease, which has killed almost 820,000 people worldwide, may continue to spread

A news-stand vendor, wearing a mask to protect against the coronavirus, sits near QR codes for Alipay and WeChat, two popular online payment system in Beijing, China on Tuesday, July 21, 2020. AP

A Hong Kong man who recovered from Covid-19 was infected again four and a half months later, in the first documented instance of human reinfection, researchers said on Monday.

The University of Hong Kong researchers said the case indicated that the disease, which has killed more than 820,000 people worldwide, may continue to spread among the global population despite herd immunity.

The man, 33, was cleared of Covid-19 and discharged from a hospital in April, but tested positive again after returning from Spain through Britain on August 15.

The patient appeared to be previously healthy, researchers said in the paper, which was accepted by the international medical journal Clinical Infectious Diseases.

Health workers wearing Personal Protective Equipment use a fingertip pulse oximeter and check the health of a resident inside the Dharavi slum during door-to-door coronavirus screening in Mumbai. AFP

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Fernanda Mariotti cradles a picture of her mother Martha Pedrotti, who died of Covid-19, at her home in Buenos Aires, Argentina. AP Photo

Health officials collect a nasal swab sample from a man to test for the coronavirus, at a civil hospital in Amritsar in India. AFP

Japan's Prime Minister Shinzo Abe arrives at the prime mnister's office in Tokyo. AFP

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Meanwhile, two European patients were also confirmed to have been reinfected with the coronavirus, regional public broadcasters said on Tuesday.

The cases raised concerns about people's immunity to the virus as the world struggles to tame the pandemic.

That has fuelled fears about the effectiveness of vaccines against the virus, although experts say there would need to be many more reinfections for these to be justified.

Broadcasters said on Tuesday that a patient in the Netherlands and another in Belgium were reinfected with the virus.

Elsewhere, British Prime Minister Boris Johnson said on Tuesday he was "really pleased" by the work teachers had done in preparing to reopen schools from next week.

Mr Johnson, whose Conservative government has come under fire for how it has tackled education during the coronavirus crisis, said it was "crucial" for all children to return to school.

He said he would look at medical evidence to see whether he should change the government's advice on wearing face masks.

"I'm really pleased by the work that teachers, schools, parents, pupils have done to get ready," Mr Johnson said on a visit in south-west England.

And in Australia, the government will spend A$1 billion ($716.80 million) to upgrade defence facilities, offer additional paid employment to army reservists and upgrade military vehicles.

Prime Minister Scott Morrison will make the announcements on Wednesday, as Canberra seeks to support its defence industry.

Australia has reported far fewer cases of Covid-19 than other developed countries, but restrictions imposed to slow the spread have had a devastating impact on the country's economy, which will slip into a recession for the first time in three decades.

In Japan, Tokyo Governor Yuriko Koike said on Tuesday that the coronavirus situation in the capital was improving and she was still intent on the city hosting the Olympics next year.

"I think the situation is much better than before," Ms Koike said.

"We will do our best to prevent coronavirus infections here in Japan and to welcome the athletes from all over the world."

She said last month that Tokyo could declare a state of emergency if the coronavirus situation deteriorated.

Daily cases had soared past 400 a day amid increased testing.

New cases have trended lower in the past week, and were at 187 in Tokyo on Tuesday.

Ms Koike said Tokyo had established many concrete measures to combat contagion, but the arrival and distribution of effective vaccines is an "essential factor" that has to be determined before the Games can go ahead.