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[ANALYSIS] What do we know about the Chinese Sinovac vaccine?

There has been much political debate over the Chinese Sinovac vaccine recently. Some media outlets are reporting that the Philippines is negotiating to secure millions of doses of this vaccine to be delivered by March.

But what exactly do we know about this vaccine? In this piece, I would like to talk about the science, the procurement, and the public perception of this vaccine.

First, the science. On July 3, 2020, a scientific team from Sinovac described their vaccine candidate in a paper published in the prestigious international journal, Science.  Their vaccine was made by inactivating or killing the COVID-19 virus called SARS-CoV2 and mixing it with chemicals that would stimulate an immune response. This technology is an established approach to making effective vaccines that was pioneered over one hundred years ago by Louis Pasteur. It is the same technology used to make the polio vaccine.

The scientific paper published in July reported that the vaccine was able to generate an immune response in mice, rats, and monkeys. Animals that were vaccinated with this Chinese vaccine were able to make powerful antibodies that killed SARS-CoV2

On November 17, 2020, another research paper was published, this time in Lancet: Infectious Diseases, which described the results of Sinovac’s phase 1/2 clinical trial. In this randomized, double-blind, clinical trial, 743 volunteers received two injections of either a low-dose or a high-dose version of the vaccine.

The reported results were positive. Safety-wise, a third of the participants experienced some reaction, mostly mild, to the vaccine. The most common symptom was injection-site pain. However, no serious reactions were noted within 28 days of the vaccination. Efficacy-wise, all of the vaccinated individuals developed antibodies against the SARS-CoV2 virus after 28 days suggesting that the vaccine was effective.

Peer review

Since the publication of the scientific paper on November 17, 2020, there have been no other peer-reviewed scientific reports on the safety and efficacy of the Sinovac vaccine. Phase 3 clinical trials are ongoing in Brazil, Indonesia, and Turkey. Nonetheless, the Sinovac vaccine received emergency use authorization in China at the end of August for high-risk groups.

Indonesian health officials have reported no serious side effects among the Indonesian volunteers who had been vaccinated with the vaccine candidate. However, and this is critical, the Sinovac vaccine’s efficacy at preventing COVID-19 has still not been reported.

Second, on procurement. There has been a lot of media and political buzz about the national government’s announcement that it is negotiating with China to obtain millions of doses of Sinovac’s vaccine. Critics have argued that this is reckless given the lack of phase 3 clinical trial data.

To be fair, the Philippines is only doing what other countries have done and are continuing to do. Because of the dire circumstances of the pandemic, many nations are signing advance purchase agreements to buy millions of doses of a vaccine before phase 3 clinical trial data for that vaccine have been released.

Just a few days ago, for example, New Zealand announced that it had agreed to purchase 10.7 million doses of vaccine from Novavax in the United States. Notably, in the same way that we do not have all the data for the Sinovac vaccine, we still do not have efficacy and safety data for the Novavax vaccine.

One thing: I was surprised to learn of the high price point for the Sinovac vaccine. According to a price list made available recently by a Filipino senator’s office, the Chinese vaccine is nearly six times more expensive than the AstraZeneca vaccine and nearly 1.5 times more expensive than its Pfizer counterpart! Why is it so expensive? The Chinese are using older and relatively less sophisticated technology to manufacture its vaccine. Labor costs in China are also not as high as those in Europe or the United States. Again, why is it so expensive?

Finally, on public perception. Last night, I spoke to my 40 third-year industrial biology (3IBIO) students here at UST about the Sinovac vaccine. I wanted to gauge their impressions because of my concerns of vaccine hesitancy in the country.

A significant number of my 3IBIO students were wary of this and any other Chinese vaccine. Citing the melamine contaminated Chinese-made milk products a decade ago, they worried that the Chinese vaccine would be also contaminated in some way. They simply do not trust Chinese medical products and are especially concerned with the lack of transparency.

Who trusts the vaccine?

One student wondered why none of the Chinese communist leadership have been vaccinated with their own vaccine: US Vice President Michael Pence was vaccinated with the Pfizer shot days after it received its emergency authorization. Why have none of the Chinese authorities been similarly vaccinated as far as we know? In fact, another student found it curious that China has just agreed to buy 100 million doses of the Pfizer vaccine when the country is developing its own.

Clearly, these university students are not representative of the Filipino population. However, if their perceptions are shared by enough Filipinos, then the national government will have a lot of work to do to convince the people to receive this vaccine.

To sum up, my students were all worried that the Philippines would receive poor quality vaccines that China would not even give its own elite.

In the end, my students have convinced me that the national government will have to answer two important questions before the Sinovac vaccine is deployed.

First, given the Chinese record of producing substandard products, how will we really know that the Sinovac vaccine is safe and efficacious? Second, given the cheaper and seemingly more effective alternatives from the West, why are we paying so much for this vaccine? –

Reverend Fr. Nicanor Austriaco, O.P. is Visiting Professor of Biological Sciences at the University of Santo Tomas, and an OCTA Research Fellow.