SINGAPORE, July 16 (Reuters) - Sinovac's (SVA.O) COVID-19 vaccine, under growing scrutiny over its effectiveness, has found a small but determined group of takers in Singapore - even though the country does not count them as being vaccinated in its official tally.
Singapore provides the more effective mRNA shots from Pfizer-BioNTech (PFE.N), (22UAy.DE) and Moderna (MRNA.O) free under its national vaccination programme but thousands have chosen to pay as much as S$25 ($18.5) for Sinovac's CoronaVac.
"I personally don't trust (mRNA) results, compared with something that is traditional, which has been used for over 100 years," said Tan Bin Seng, a retired Singaporean doctor, referring to inactivated-virus vaccines.
Some see no downside to taking the China-made vaccine, which is based on more established technology, as cases in Singapore are few. They say they are less confident in the long-term safety of newly developed messenger RNA (mRNA) vaccines.
Infectious diseases expert Leong Hoe Nam said many of the locals signing up at his Rophi Clinic for Sinovac were in their 60s and echoed such fears.
Safety concerns have been amplified on social media, where locals share posts and experiences about the side effects of the mRNA vaccines.
Europe's drug regulator last week said it had found a possible link between very rare heart inflammation and mRNA COVID-19 vaccines from Pfizer-BioNTech and Moderna, in line with U.S. findings last month, though both said benefits of the shots far outweigh the risks. read more Allergic reactions have been also reported after mRNA shots.
So far, regulators have mostly raised concerns about Sinovac's efficacy, and there have been few reports of adverse effects.
Private clinics in Singapore had given more than 17,000 doses of CoronaVac as of early July. read more More than 6 million total doses of mRNA vaccine have been given in the city-state, and about 2.4 million people are fully vaccinated with them.
As of July 1, Pfizer has shipped more than 860 million doses of its COVID-19 vaccine worldwide.
Singapore, which has made vaccination a key pillar of its reopening plans, has reported many fewer cases than its neighbours, where fresh outbreaks have raised doubts about CoronaVac's efficacy against new virus variants.
Thailand this week said it would use the AstraZeneca (AZN.L) vaccine as a second dose for those who received the Sinovac shot, while Indonesia is considering a booster shot for those who received the two-dose Sinovac course.
The mRNA vaccines have shown efficacy rates of well over 90% against symptomatic disease in clinical trials, compared with trials for Sinovac that have shown results from as low as 51% to about 84%.
"There is no harm in taking Sinovac, its efficacy rate may be relatively lower but the risk of getting COVID-19 in Singapore is very low," said Singapore-based Chinese national Luo Qiufeng, 25.
Singapore, which has close ties with Beijing and Washington, gave the Sinovac vaccine an early vote of confidence through an advance purchase announced in December, which also included Moderna and Pfizer-BioNTech.
But it has only allowed private clinics to give the Sinovac vaccine after last month's emergency use approval by the World Health Organization (WHO).
"Singapore doesn't want to upset Beijing," said Chong Ja Ian, a political science professor at the National University of Singapore. With Sinovac, it has taken an "in-between route", where it is allowing people to take it if they want, but not really endorsing it, he said.
Singapore's health ministry has said that making CoronaVac available at private clinics allows access for those who do not wish to take the approved vaccines and that it was better to have some form of protection against COVID-19 than no protection at all.
Singapore-based Chinese citizens say they were also encouraged by vague online messages that imply China-made vaccines will make it easier to travel home. China does not have such a policy, and official government guidance states travellers will have to quarantine, regardless of vaccination status.
"It just feels like China would give more recognition to Chinese-made vaccines," said Chinese software engineer Cedric Lin, 29.
StarMed Specialist Centre had vaccinated 1,500 people, with another 4,000 bookings, CEO Louis Tan said. Half of the demand was coming from Chinese nationals, while the rest was mainly from ethnic Chinese Singaporeans.
Singapore has said it would not count Sinovac takers in its vaccination tally because of inadequate data, especially against the highly contagious Delta variant.
Incentives for being vaccinated under the national programme include not having to be tested for COVID-19 before attending some events. Those who have taken CoronaVac will still need to be tested.
The move has triggered an online petition to treat Sinovac like mRNA shots. About 2,000 people have signed it.
(This story was refiled to change StarMed Medical Centre to StarMed Specialist Centre in paragraph 21)
Our Standards: The Thomson Reuters Trust Principles.