Dr Kiattiphum said the study was conducted on 386 patients in Phuket with COVID-19, noted a report by the Bangkok Post.
The study found that six patients who had already received two doses of the Sinovac vaccine did not develop a lung infection, he said.
Only four of 31 people who became infected after receiving their first vaccination injection did have a lung infection, he added, said the report.
A separate study was also conducted on 1,366 high-risk people who had been quarantined for 14 days.
The study found that the Sinovac vaccine was 73.1% effective at reducing the risk of infection among first-dose recipients, Dr Kiattiphum said.
The study found the Sinovac vaccine reduced the risk of infection by 83.3% in patients, he added.
According to the report, Dr Kiattiphum said that some 22% of people in Phuket had received two injections of “COVID-19 vaccine”, at this stage presumed to be the Sinovac vaccine, while 45% had received their first injection.
However, at last report by the Phuket office of the Public relations Department (PR Phuket), as of May 21, 162,225 people in Phuket had received at least one COVID vaccination injection.
The PR Phuket report noted that the number of vaccination injections at that time amounted to 34% of the target 466,587 to be administered for the island to achieve its goal of vaccinating 70% of the island’s population.
PR Phuket and the Phuket Provincial Public Health Office (PPHO) have not released any updates to the number of people in Phuket to have received vaccination injections since that report, posted on May 22.
Meanwhile, Dr Kiattiphum said that as of May 17, there were no new infections in Phuket among people who had received two doses of teh Sinovac vaccine, said the Bangkok Post report.
Dr Kiattiphum warned that people should still wear masks, practise social distancing, and wash their hands frequently and maintain personal hygiene even if they have received two doses of the vaccine.
On containing COVID-19 in various clusters in upcountry areas, public health authorities moved quickly to detect infections and set up field hospitals to handle them. Dr Kiattiphum said 70% of people will be vaccinated by October, said the Bangkok Post report.
The government’s committee on national tourism policy earlier this month confirmed a plan to reopen Phuket to foreign visitors. That is due to begin on July 1, the report added.
News of the study promoting the effectiveness of the Sinovac vaccine follows a 43-year-old man from Phang Nga dying of a heart attack one day after receiving his first Sinovac injection at Phuket airport.
The man was known to have high cholesterol, but was reported by his wife to be otherwise healthy and said to enjoy playing sport.
Health officials are investigating the man’s death.