Vaccines featured prominently in a Southeast Asian tour by Chinese Foreign Minister Wang Yi this month, just as the efficacy of one of his country’s vaccines was drawing scrutiny around the world.

During a trip widely seen as China’s bid to shore up relations with its Association of Southeast Asian Nations (Asean) neighbours before a possible policy shift by the incoming Biden administration, Wang said China would give half a million free vaccine doses to the Philippines – widely believed to be the one developed by Sinovac, although Wang did not specify.

Wang also offered 300,000 doses to Myanmar, reportedly including vaccines produced by both Sinopharm and Sinovac, with “a batch” of the doses to be free.

The donations were made as the Butantan Institute, Sinovac’s partner in Brazil, dropped a bombshell by saying its trials had found Sinovac’s vaccine CoronaVac to be only 50.4 per cent effective. This referred to its data for general efficacy – protection against all severities of Covid-19 including mild cases not requiring treatment.

How well Chinese vaccines perform in late-stage clinical trials has drawn worldwide attention, with high expectations that China could help fill a supply gap for developing countries after most Western vaccines were snapped up by rich countries.

Butantan’s announcement whipped up political bickering in the Philippines, with some lawmakers arguing CoronaVac was too expensive given its apparently low efficacy, while regulators from some other places said they would review the data further.

However, developing countries continue to scramble for Chinese vaccines, and China for its part has redoubled its efforts to use what some have termed “vaccine diplomacy” – although China’s diplomats and state media resist using the label – to pursue its foreign policy goals.

In the longer term, the vaccine supply landscape for developing countries may change as the United States under its new president, Joe Biden, relinquishes the “vaccine nationalism” touted by the Trump administration and joins the global distribution initiative Covax.

After Butantan announced its efficacy data on January 12, Sinovac broke its long silence on its trial data to defend CoronaVac.

Sinovac said efficacy rates for different strata of the overall 50 per cent efficacy in Brazil’s trials showed CoronaVac to be 100 per cent effective in protecting against severe cases and 78 per cent effective in protecting people developing symptoms requiring treatment.

The efficacy rate on severe cases, however, has yet to be based on enough cases to make the distinction statistically significant.

The company also said the trials were conducted on health care workers, arguing the efficacy in protecting them may have been affected because they would have been constantly exposed to Sars-CoV-2, the coronavirus that causes Covid-19.

The Pfizer-BioNTech and Moderna vaccines both reported efficacy of about 95 per cent, while the Oxford-AstraZeneca vaccine was found to be 70 per cent effective.

But even with an efficacy of 50 per cent, scientists said it was an important supply line for developing countries.

“It is not yet known if the reduced efficacy of (CoronaVac) reflects weaker immune responses or different populations,” said Dan Barouch, director of the virology and vaccine research centre at Harvard’s Beth Israel Deaconess Medical Centre, who is co-developing a Covid-19 vaccine with Johnson & Johnson.

“Still, a vaccine with 50.4 per cent efficacy could have an important role in areas that currently do not have access to other vaccines.”

Sinovac also pointed to the better interim efficacy data in trials in Turkey, which are ongoing, and Indonesia, at 91 per cent and 65 per cent respectively. But Turkey’s 91 per cent efficacy was based on a small cohort of 1,322 volunteers out of the 7,800 recruited as of mid-December, while the Indonesian trial involved only 1,700 volunteers

Serhat Unal, professor in medicine at Hacettepe University, who coordinated those clinical trials in Turkey, said the aim was to recruit 13,000 volunteers and wait to reach 40 infections among them before making final efficacy analysis.

Jerome Kim, director general of the International Vaccine Institute, said it was important for trials in different countries to use the same protocols if the company wanted to combine the findings.

Sinovac chairman Yin Weidong last week said the three overseas trials were designed differently, without stating whether the firm intended to present a combined result later.

“(The protocols) were conducted independently by three different research (institutes),” he said. “All the findings were done by the researchers from the different countries independently.”

Kim said confusing data released by Sinovac and its partners would undermine public trust.

“When you only present a part of the data, then have to amend it, it damages your credibility,” he said. “For vaccine companies, credibility is important. We are going to give this vaccine – if safe, efficacious and manufactured at an international standard of quality – to healthy people to keep them healthy. Being able to stand with strong data on safety and efficacy is critical assurance.”

Huang Yanzhong, senior fellow for global health at the Council on Foreign Relations in New York, said lower efficacy may affect people’s willingness to take a vaccine if they have other choices, and it may take longer for developing countries to achieve herd immunity because higher vaccination rates would be required.

“Countries may face domestic pressure in terms of purchasing the China-made vaccines,” he said……

In terms of prices paid by governments, Chinese vaccines are more expensive than the Oxford-AstraZeneca one, though they should be cheaper than the mRNA vaccines.

www.msn.com/en-xl/news/other/china-s-covid-19-vaccines-in-demand-but-will-efficacy-data-affect-its-diplomacy-goals/ar-BB1d3tgF