Brazilian researchers announced Thursday that Sinovac’s new coronavirus vaccine is safe and effective based on the result of phase III clinical trials in the country. That data is being submitted to Anvisa, the country’s regulatory authority, for emergency use application.
The much-awaited announcement, which has been delayed multiple times, was released with very few details, which raised some questions. Researchers at the Butantan Institute, a state-owned biologic research center that oversaw the vaccine’s phase III trials in the country, only said that results showed the vaccine was 100% effective in preventing severe symptoms of COVID-19, and 78% effective in preventing mild cases of COVID-19. The trial included 13,000 volunteers, 218 of which got COVID-19. Over 160 of those cases occurred in the placebo group.
“Throughout the pandemic we’ve seen a worrying trend of science by press release, without full disclosure of trials data, and the announcement by the Butantan Institute on the Sinovac vaccine provides very little data.”— Jonathan Cushing, head of the global health program, Transparency International
However, more data was left out that is critical to gain a better understanding of the vaccine and its performance.
“The availability of more data is essential to understand any vaccine — for example, age groups of those tested, did this group have any unusual characteristics, how were they selected, how were the clinical and laboratory endpoints defined, what were the rates of individual side effects, what was used for the placebo, how were the statistics done, where did the vaccine come from, doses and so on,” Dr. Keiji Fukuda, director and professor, University of Hong Kong School of Public Health, told Devex in an email.
“All of these are very basic parameters that should be made available to peer scientists, who can then ask further questions in order to understand the product’s performance as well as possible,” he added.
Several Southeast Asian countries — including Vietnam, Malaysia, and the Philippines — are hoping to finalize deals with Sinovac, the Chinese vaccine manufacturer behind the CoronaVac vaccine, despite limited data on the vaccine’s efficacy and safety to date. Delays in the release of efficacy results from its phase III trials have raised questions and created uncertainties on the timelines set by governments to commence vaccinations, as well as countries’ access to finance to purchase the vaccines.
“At this point, we don’t necessarily have data that would say that Sinovac is safe and efficacious,” Dr. Jerome Kim, director-general of the International Vaccine Institute told Devex, adding that the announcement made in Brazil provides little information.
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Publishing full data from clinical trials is critical not just for patient safety, but also to build public trust in COVID-19 vaccines. This is important, especially in the Brazilian context where there’s low public trust in the vaccines, said Jonathan Cushing, head of Transparency International’s global health program.
“Throughout the pandemic we’ve seen a worrying trend of science by press release, without full disclosure of trials data, and the announcement by the Butantan Institute on the Sinovac vaccine provides very little data,” he said.
“Given that the vaccine is due to be rolled out this month, it is imperative that Sinovac and their partners release details of their clinical trial results immediately to allow for proper peer review of the results, and to instil trust,” Cushing added.
While pursuing other Western vaccine candidates, Vietnam, Malaysia, and the Philippines are also eyeing deals with the Chinese vaccine manufacturer.
In the Philippines — the country with the second-largest caseload of COVID-19 in Southeast Asia — the government had discussions with the vaccine manufacturer for a vaccine supply of 25 million doses by March 2021. Philippines’ Food and Drug Administration Director General Eric Domingo said this week that Sinovac has asked for information regarding requirements for emergency use authorization of its vaccine in the country.
Amid criticisms of giving favor to Chinese vaccines, the government has said it is also pursuing vaccines from other manufacturers. But there are big challenges in supply given global demand for some of these vaccines.
Some countries have already inked deals and are gearing up for vaccination with Sinovac’s COVID-19 vaccine.
Singapore, the first and only country in the region to have started vaccinations using Pfizer-BioNTech’s BNT162 vaccine, has made advance purchase agreements with Sinovac.
Indonesia has received 3 million vaccine doses of a reported 125 million, as part of its supply deal with Sinovac, and aims to start vaccination on Jan. 13. It’s unclear whether it will go on as planned given regulatory authorities have yet to receive the vaccine’s clinical trial results, pending regulatory approval.
But the head of Indonesia’s Food and Drug Authority, Penny Lukito, said in a news briefing on Friday that an emergency use authorization will be issued before the government’s targeted vaccination schedule, according to Kompas.com.
In December, Indonesia’s state-owned vaccine manufacturer Bio Farma said the interim report from the vaccine’s phase III trial in Indonesia will be submitted to Badan POM, Indonesia’s regulatory authority, this month.
Authorities in Hong Kong, hoping to start vaccinations in February with Sinovac’s COVID-19 vaccine, are also waiting for Sinovac to release the much-anticipated data.
Thailand said this week that it has secured 2 million doses from the manufacturer and expects the first 200,000 doses to arrive in February. The government has also secured vaccine doses from AstraZeneca-Oxford. The first doses are expected to arrive in the second quarter of the year.
Kim said countries that have engaged early with the manufacturer, even before efficacy results are known, “seem to be better positioned to receive doses now.”
Cold chain requirements for Sinovac’s vaccine are also at 2-8 degrees Celsius (35-46 degrees Fahrenheit) — similar to AstraZeneca-Oxford’s COVID-19 vaccine for instance — making it easy to transport and store.
A number of high-income countries in 2020 pursued some of the current in-demand COVID-19 vaccines even before efficacy results were released. The United States was able to secure 600 million doses of Pfizer-BioNTech’s BNT162 vaccine in July 2020, even before the companies began phase 2b/3 clinical trials.
In December, Philippine Presidential Spokesperson Harry Roque said interest in Sinovac’s vaccine is due in part because it can be made available to the Philippines earlier than others.
However, the important question — how safe and efficacious the vaccine is — remains unknown.
“The announcement by one of the sites for the Global Efficacy trials of Sinovac is not what we were hoping for,” Kim said.
The announcement comes as COVID-19 cases reach over 69 million globally with over 1.5 million deaths and on the heels of regulatory approvals in the U.K., Bahrain, and Canada of the Pfizer-BioNTech COVID-19 vaccine.
There are also questions on the level of neutralizing antibodies the vaccine is able to produce, he said. Results from phase 1 and 2 trials of the vaccine, published in The Lancet, showed neutralizing antibodies were lower in trial participants compared to those who have recovered from COVID-19. The vaccine also produced lower levels of neutralizing antibodies compared to other vaccine candidates such as AstraZeneca and Pfizer.
Data from Sinovac’s phase III trials will be crucial, not only in getting countries’ regulatory approval but also for low- and middle-income countries hoping to access financing from the Asian Development Bank’s Asia Pacific Vaccine Access Facility, launched in December.
The facility is meant to help the bank’s low- and middle-income member countries procure and deliver COVID-19 vaccines. But it comes with strict criteria: the vaccine must be procured via the global vaccine initiative — more commonly known as COVAX, which aims for an equitable distribution of COVID-19 vaccines. If not, the vaccine should at least receive prequalification from the World Health Organization, or receive regulatory approval from a “stringent regulatory authority.”
Only Pfizer-BioNTech’s COVID-19 vaccine has received WHO’s emergency use listing recommendation to date, although WHO expects to receive Sinovac’s vaccine dossier for review this month. Meanwhile, Sinovac has received emergency use authorization in China. But an ADB spokesperson said the vaccine has not met the facility’s eligibility criteria, as China is not listed among WHO’s Stringent Regulatory Authorities.