Singapore latest to cast doubt over Chinese Sinovac efficacy. Here’s why

Singapore has included only Pfizer and Moderna vaccines in its national vaccination program but has allowed private health clinics to administer Sinovac.

Singapore top health officials are the latest to cast doubt on the efficacy of vaccines manufactured by the Chinese company Sinovac, even as the island city-state started administering the shots on Friday, according to the New York Times. Citing cases of Indonesia, Kenneth Mak, Singapore’s director of medical services, said that he was worried about reports of people vaccinated with Sinovac getting sick with coronavirus disease (Covid-19), reported NYT.

Singapore has included only Pfizer and Moderna vaccines in its national vaccination program but allowed private health clinics to administer Sinovac.

“It does give the impression that the efficacy of different vaccines will vary quite significantly,” Times quoted Mak as saying.

Last month, the World Health Organization (WHO) issued an interim recommendation for use of the Sinovac-CoronaVac vaccine for inoculation against coronavirus disease (Covid-19). Phase 3 trials of Sinovac-CoronaVac around the world have reported the effectiveness of vaccine between 50 and 84 per cent.

However, Indonesian officials earlier this week revealed that more than 350 doctors and medical workers have been infected and dozens hospitalised despite being vaccinated with Sinovac, raising concerns about the vaccine against more infectious variants.

While most of the workers were asymptomatic, dozens were hospitalised with high fevers and falling oxygen-saturation levels, according to a senior health official in central Java. Indonesian healthcare workers were among the first to be inoculated against the virus when the vaccination started in the country in January.

The Indonesian Medical Association (IDI) said that almost all of them received the Covid vaccine developed by Sinovac. District of Kudus in Central Java is battling a Covid outbreak believed to be driven by a more transmissible Delta variant, first detected in India.

"The data shows they have the Delta variant (in Kudus) so it is no surprise that the breakthrough infection is higher than before, because, as we know, the majority of healthcare workers in Indonesia got Sinovac, and we still don’t know yet how effective it is in the real world against the Delta variant,” said Dicky Budiman, an epidemiologist at Australia's Griffith University.

Singapore has included vaccines manufactured only by Pfizer-BioNTech and Moderna in its national vaccination program but allowed 24 private health clinics to administer Sinovac following authorisation by the WHO. Despite the availability of Pfizer and Moderna vaccines, with 90% effectiveness in preventing infection, many in Singapore would choose to get Sinovac because they are either from mainland China or plan to travel there, according to Times.

Brazilian President Jair Bolsonaro had initially bashed the “origin” of Sinovac-CoronaVac and refused to buy it. While doctors say residents should get any shot available, Brazilians are spurning Sinovac’s CoronaVac, which they believe are substandard, in favour of hard-to-find Pfizer shots, reported Bloomberg.

(With inputs from agencies)