The first of the China-developed Sinovac Covid-19 inoculations will be administered at selected private clinics in Singapore Friday, following health authorities' approval of 24 private clinics to draw on the government's existing inventory of the vaccine.

There was a queue of around 10 people outside Little Cross Family Clinic in Tampines Street Friday morning, making inquiries about the vaccine. As of Thursday, Singapore has reported 62,366 cases of the virus and 34 deaths.

In Vietnam, the country's infection tally of its new Covid-19 wave climbed to nearly 9,000 Friday morning with 81 new cases added and 60 of them are in Ho Chi Minh City.

Of the cases in Vietnam's biggest city, 51 have had direct contact with previously confirmed cases, four linked to the church cluster emerging May 26 in Go Vap District, officials said.

Meanwhile, a senior China epidemiologist said the U.S. should be the priority in the next stage of investigations into the origin of Covid-19 after a study showed the virus could have been circulating there as early as Dec. 2019, state media said.

Focus should shift to the U.S., which was slow to test people in the early phases of the outbreak, and is also the home of many biological laboratories, Zeng Guang, chief epidemiologist with China's Center for Disease Control and Prevention, told state-run tabloid Global Times.

"All bio-weapons related subjects that the country has should be subject to scrutiny," Zeng said.

A previous study has raised the possibility that the virus could have been circulating in Europe as early as September 2019, but health experts said this did not necessarily mean the disease did not originate in China, Reuters said.

In the Philippines, 1.5 million additional doses of Chinese-developed Sinovac vaccines arrived Thursday morning, the National Covid-19 Task Force said.

It is the third batch and so far the largest delivery of the CoronaVac vaccine to the country this month. The Philippines received 1 million doses of the same vaccine June 8 and 10.

In Malaysia, the government's Covid-19 immunization rate hit another high Thursday as 221,706 shots were administered throughout the country.

Some 177,876 people were given their first dose while 43,830 got their second dose, the Special Committee on Ensuring Access to Covid-19 Vaccine Supply said.

In Thailand, officials have given up attaining herd immunity as the government races toward fully reopening the country's borders to foreign visitors, and as Prime Minister Prayuth Chan-ocha assesses economic imperatives against risks to public health.

"I know this decision comes with some risk because, when we open the country, there'll be an increase in infections, no matter how good our precautions," Nikkei Asia quoted the prime minister as saying.

Over in Indonesia, more than 350 doctors and medical workers have been infected with Covid-19 despite being immunized with Sinovac. Officials said dozens have been hospitalized, as concerns grow about the effectiveness of some vaccines against more infectious variants.

Worldwide, there are 177 million Covid-19 cases. Some 3.84 million have died from the disease.