The public health ministry of Thailand on Sunday (Jul 11) said more than 600 medical workers who received two doses of China’s Sinovac vaccine have been infected with Covid-19 as local authorities weigh giving booster doses to raise immunity., Reuters reported.

The announcement comes as Thailand reported a total of 336,371 confirmed infections and 2,711 fatalities since the pandemic began last year.

Of the 677,348 medical personnel who received two doses of Sinovac, 618 became infected, health ministry data from April to July showed. A nurse has died and another medical worker is in critical condition.

An expert panel has recommended a third dose to trigger immunity for medical workers who are at risk, Sopon Iamsirithaworn, the Department of Disease Control deputy director-general, told a news briefing on Sunday.

"This will be a different vaccine, either viral vector AstraZeneca or an mRNA vaccine, which Thailand will be receiving in the near term," Dr Sopon said, adding that the recommendation will be considered on Monday.

The majority of medical and frontline workers were given Sinovac's shots beginning in February, with the viral vector vaccine from AstraZeneca arriving in June.

Thailand is expecting a donation of 1.5 million Pfizer-BioNTech vaccines from the United States later this month and has ordered 20 million doses that will be delivered after October.

In the neighbouring Indonesia, 131 health care workers, mostly vaccinated with the Sinovac shot, have died since June, including 50 in July.

Earlier last week, Indonesian health minister Budi Gunadi Sadikin defended the country’s use of China’s Sinovac vaccine, blaming a surge of Covid-19 cases over the past month on the more contagious Delta variant.

Indonesia, which has also heavily relied on Sinovac, said on Friday it would give the Moderna vaccine as boosters to medical workers.