Sinovac vaccine is only 50.38% effective 2:25
Hong Kong (CNN) -
Public mass vaccination programs using a Chinese coronavirus vaccine are underway in Indonesia and Turkey, where tens of millions of people are expected to receive doses of the CoronaVac vaccine, made by the Sinovac company, with headquarters in Beijing.
On Wednesday, Indonesian President Joko Widodo appeared receiving the country's first dose of CoronaVac vaccine, after the government cleared it for emergency use.
On Thursday, meanwhile, Turkish President Recep Tayyip Erdogan announced that he had also been vaccinated.
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However, these vaccination programs come despite growing doubts about the effectiveness of the drug, which last week was revealed to have an efficacy rate of only 50.38% in late-stage trials in Brazil, significantly lower than previously. which showed the previous results.
That rate barely crosses the 50% efficacy threshold set by the World Health Organization, and is much lower than the 78% previously announced with much fanfare in China earlier this month.
The apparent discrepancy has raised concern among some scientists and shaken international confidence in vaccines made in China.
"Since many countries are planning to order, or have already ordered, Sinovac vaccines, this could undermine people's willingness to take them, because people may question the usefulness of the vaccines," said Yanzhong Huang, senior global health researcher. at the US-based Council on Foreign Relations and an expert on the Chinese health system.
"It could be a potential obstacle."
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The Brazilian results suggest that CoronaVac is much less effective than the vaccines developed by Pfizer-BioNTech and Moderna, which have an efficacy rate of approximately 95%.
Russia says its Sputnik V vaccine is 91% effective, while the UK vaccine, developed by the University of Oxford and AstraZeneca, has an average efficacy of 70%.
Sinovac's vaccine has a lower efficacy rate than its national rival, developed by state-run Sinopharm, which says it is 79.34% effective.
Employees work on the production line of CoronaVac, Sinovac Biotech's vaccine against the coronavirus Covid-19 at the Butantan biomedical production center, in Sao Paulo, Brazil, on January 14, 2021.
Chinese vaccines in review
The Sinovac and Sinopharm vaccines have been considered candidates for potentially affordable and readily available vaccines.
Unlike Pfizer-BioNTech and Moderna vaccines, Chinese vaccines do not require expensive cold storage.
Sinovac has agreements in place with at least six governments, with plans to provide 46 million doses of its CoronaVac vaccine to Brazil, 50 million doses to Turkey and 7.5 million doses to Hong Kong.
It will also supply 40 million doses of the vaccine in bulk (the vaccine concentrate before dividing it into vials) to Indonesia for local production.
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Thailand ordered 2 million doses of CoronaVac and expects to receive the first 200,000 doses in February, while the Philippines ordered 25 million doses, of which the first batch is also expected to arrive next month, according to Reuters.
However, following the publication of the Brazilian trial data, other countries are now reexamining potential plans.
Singapore's Health Minister said officials would review the Sinovac vaccine before applying it to their citizens.
Singapore has not approved the vaccine, but has a purchase agreement with the company.
Health Minister Gan Kim Yong said the vaccine should go through a regulatory process and approval by the Singapore Health Sciences Authority, according to the Straits Times.
Malaysia also said it would seek more data from Sinovac before approving and purchasing supplies, Reuters reported, while in Hong Kong, which signed an agreement with Sinovac, a senior medical adviser said a panel of experts would review each vaccine based on clinical data.
Despite the fact that Brazil's health agency regulator Anvisa voted in favor of authorizing the emergency use of Sinovac's CoronaVac vaccine on Sunday, it said it did not have access to important data about the vaccine in the study by Phase 3, such as the duration of protection provided by the vaccine and its effect on older adults and other specific groups, such as people with comorbidities.
Brazil authorizes two covid-19 vaccines for emergency use
Brazil's national vaccination program is scheduled to begin on January 20, according to the Ministry of Health.
And while the governments of Thailand and the Philippines have so far publicly endorsed the launch of Sinovac, politicians from both countries have questioned their implementation plans.
In response to concerns, Thai regulators have asked Sinovac to provide more detailed information on clinical trials.
On Wednesday, Sinovac defended the safety and efficacy of his vaccine.
"These Phase 3 clinical trial results are sufficient to demonstrate that the safety and efficacy of the CoronaVac vaccine are good worldwide," company president Yin Weidong said at a news conference, according to Reuters.
Different efficacy rates
Part of the confusion about the Sinovac vaccine revolves around the different efficacy rates and available data.
Turkey, which approved the Sinovac vaccine for emergency use on Wednesday, reported an efficacy of 91.25%, while Indonesia reported 65.3%.
Data from Brazil, meanwhile, showed an efficacy of 50.38% for those who suffered very mild cases of covid-19.
But the rate increased to 78% for mild to severe cases.
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“It is difficult to interpret all this information without looking at the complete data sets.
This highlights the problem of issuing data through press releases rather than publishing it in a peer-reviewed journal, ”Professor Lawrence Young, virologist and professor of Molecular Oncology at the University of Warwick, said in a statement.
"It also highlights the different approaches to the requirements for regulatory approval."
There are several reasons why one trial might produce a different efficacy rate than another, including the way they were done, or that the vaccine might be more or less effective in different age groups or different population groups, experts say. .
A Sinovac representative told CNN that the discrepancy in the results was due to different situations in the countries where clinical trials were conducted.
"The results are from different populations, in different places with different morbidity rates, and therefore cover a relatively large range," said the representative.
But amid the vast amount of information about new vaccines coming out every day, analysts say there is a risk that people may become confused and lose confidence.
"There is a danger of people misunderstanding science," said Dr. Nikki Turner, director of the Immunization Advisory Center at the University of Auckland in New Zealand.
“There is a really important point here about trying to effectively communicate the science behind these vaccines.
Especially when things are moving very fast.
And efficacy may not necessarily mean how effective the vaccine turns out to be.
"Once the vaccine moves from clinical trials to the community, you need to think broadly about the different aspects of what makes a vaccine work," Turner said.
"Some vaccines may be more effective at reducing disease, some vaccines may be more effective at reducing transmission, so it depends on what your goal is."
Where they are most needed
The concern that a country depends on a single vaccine with a lower efficacy rate is that it cannot necessarily develop the required herd immunity in a population.
That debate unfolded this week in Australia, where some scientists proposed a delay in large-scale vaccination.
Australia has obtained 54 million doses of the AstraZeneca vaccine from the University of Oxford and has plans to start implementing it later this year.
However, some scientists, including the president of the Australian and New Zealand Society for Immunology, have argued that the vaccine will not provide herd immunity and implementation plans should be halted, citing its low rate of efficacy compared to vaccines manufactured in USA
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Australia's chief medical officer, Paul Kelly, tried to ease such concerns, saying that "AstraZeneca is, based on the evidence we have so far, a safe and effective vaccine."
And he added that more data is expected.
Experts have said that while the scientific discussion about the availability of new data is a good thing, it should not detract from the fact that all vaccines that have been approved in countries around the world have been shown to be safe and effective in stopping death and serious illness.
Sinovac's Chinese vaccine has low effectiveness, according to Brazilian health authorities
Australia has recorded fewer than 30,000 COVID-19 cases and fewer than 1,000 deaths, according to Johns Hopkins University.
Several other nations in the Asia-Pacific region that have had similar success in controlling the pandemic have vaccine purchase agreements, but appear to be waiting for more data and to see what happens during large-scale vaccination in the more nations. affected, before vaccinating their own citizens.
New Zealand has been hailed as a global model for its handling of the outbreak;
has not had a case of local transmission since November 18.
No vaccine has been approved in the country, although it has reached agreements with several vaccine developers to access their candidates once local regulators give the green light.
Turner, from the University of Auckland, believes that waiting and evaluating new data on the safety and efficacy of vaccines will mean that the population can have greater confidence in them.
“There are communities around the world that are nervous about new vaccines, new vaccine technology.
Are they safe?
Are they effective?
So if we don't have to rush emergency decisions with preliminary data, we are in a good position to wait a few more months and get more comprehensive data on the effectiveness and safety of these vaccines, "he said.
However, waiting too long could risk another outbreak, particularly given the potentially more transmissible newer variants.
"This is a balancing act between introducing vaccines into the country to jump-start the economy and trying to prevent the disease from entering our country, versus moving forward and losing the trust of the community," Turner said.
Jamie Triccas, professor of medical microbiology at the University of Sydney's faculty of medical sciences, said that with the pandemic still raging, multiple vaccines from various vendors should be considered, and it's important to use all of them.
“The main thing is that we want to stop the deaths, that's the first thing you want.
If you vaccinate as many people as you can, you know that the vaccine may not prevent everyone from getting infected, but that it is good at stopping serious infections, hospitalizations and deaths, "he said.
Time is not on our side.
We are in a situation where we have more deaths and cases per day than ever.
It is time to cooperate and get all the vaccines out as quickly as possible, as long as they are safe and have an agreed level of efficacy as effective.
CNN's Nectar Gan and Jadyn Sham contributed reporting from Hong Kong and Rodrigo Pedroso contributed reporting from Sao Paulo.
China coronavirus vaccine