BEIJING, June 29 (Reuters) - Many countries from China to Indonesia and Brazil rely heavily on Chinese vaccines to inoculate their people against COVID-19, but there are growing concerns about whether they provide enough protection against the Delta variant, first identified in India.
June 29, 2021
12:07 PM +08Last Updated 3 days ago
Doses of the Chinese Sinopharm vaccine against the coronavirus disease (COVID-19) are seen at the Biblioteka kod Milutina restaurant in Kragujevac, Serbia, May 4, 2021. REUTERS/Marko Djurica/File Photo
Below are views from China's health experts about the effectiveness of home-grown vaccines against the Delta, which is becoming the globally dominant variant, and virus preventive measures China is taking.
DO CHINESE VACCINES WORK AGAINST DELTA?
China has not provided vaccine effectiveness results against the variant based on large-scale data in clinical trials or real-world use, nor offered detailed information from lab tests, but Chinese experts are urging people to get inoculated as soon as possible.
The lack of detailed data on the Chinese vaccines against the Delta has hobbled any meaningful peer reviews by foreign experts.
Researchers found that Chinese vaccines are somewhat effective in reducing the risk of symptomatic and severe cases caused by Delta, Zhong Nanshan, a epidemiologist who helped shape China's COVID-19 response, told reporters.
It is based on analysis of infections in Guangzhou city, and Zhong told Reuters the results are preliminary and the sample size is small.
Sinovac spokesman Liu Peicheng told Reuters preliminary results based on blood samples from those vaccinated with its shot showed a three-fold reduction in neutralizing effect against the Delta.
He said a booster shot following the two dose-based regimen could quickly elicit stronger and more durable antibody reaction against the Delta. However, he didn't provide detailed data.
Antibodies triggered by two Chinese vaccines are less effective against the Delta compared with other variants, Feng Zijian, former deputy director at the Chinese Center for Disease Control and Prevention, told state media last week.
Feng did not provide details including the name of the two vaccines.
The shots could still offer protection, since none of those vaccinated in southern Guangdong province, where China's first cases of the Delta variant were found, developed severe symptoms. All severe cases are from unvaccinated people.
Jin Dong-Yan, a virologist at the University of Hong Kong, said Feng's comment alone is not enough to back up the claim that Chinese vaccines are effective against severe cases, as more data is needed.
Indonesia, which has reported record daily cases recently due to a surge in the Delta variant, saw hundreds of medical workers infected by the COVID-19 despite being vaccinated with Sinovac's shot, officials said earlier this month.
It was not immediately clear, however, if the Indonesian medical workers were infected by the Delta variant.
That compared with 93% effectiveness against the Alpha variant, first identified in Britain.
Two doses of the AstraZeneca (AZN.L) vaccine were 60% effective against symptomatic disease from the Delta compared with 66% effectiveness against the Alpha, PHE said.
There is no substantial data showing how protective Johnson & Johnson's (JNJ.N) single-dose COVID-19 vaccine is, and U.S. infectious disease experts are weighing the need for booster shots using mRNA vaccines.
HOW SEVERE WAS THE GUANGDONG OUTBREAK?
Guangdong, China's major manufacturing and export hub, became the country's biggest cluster of Delta cases since reporting its first locally transmitted Delta variant infection in May.
The Delta infections included 146 cases in Guangdong's capital Guangzhou and several cases from the southern tech hub of Shenzhen and nearby Dongguan city.
No new domestic transmissions of any variant have been reported in the province from June 22.
WHAT CHINA HAS DONE?
Guangdong, which has 126 million people, has fast-tracked its vaccination effort since the outbreak. It had administered just 39.15 million doses as of May 19, but the number shot up to 101.12 million by June 20.
Guangzhou, Shenzhen and Dongguan quickly sealed off neighbourhoods where those who were infected and their contacts visited and launched multiple rounds of mass testing, following the protocols observed during previous outbreaks.
The cities also required those travelling out of the province to show proof of negative COVID-19 test results.
Zhong, the epidemiologist, said that without effective control measures 7.3 million people in Guangzhou city would have been infected in the first 20 to 30 days after the initial case.
Chinese COVID-19 vaccine maintains protection in variant-plagued Brazil
As potentially more dangerous coronavirus variants spread worldwide, scientists and clinicians have raced to discover how well the available COVID-19 vaccines protect against the mutant strains.
Preliminary results from a large study of health care workers now suggest one dose of CoronaVac, a vaccine developed by a Chinese company, is still about 50% effective against symptomatic COVID-19 in a Brazilian city where more than three-fourths of new cases are caused by the highly transmissible variant known as P.1.
A woman in São Paulo eyes the syringe about to be used to give her a shot of Sinovac’s COVID-19 vaccine.
ANDRE PENNER/AP
That real-world protection is about the same level clinical trials saw with two doses of CoronaVac against the standard, or “wild type,” pandemic coronavirus in the country, suggesting the variant’s mutations have not increased SARS-CoV-2’s ability to evade vaccine-evoked immune responses.
“This is very good news and supports the continued use of this vaccine in Brazil and other countries with the circulation of the same variant,” says Julio Croda, a physician and researcher at the Oswaldo Cruz Foundation, who led the study. The vaccine’s protection may be even better after the second dose, he adds, noting the study is ongoing.
Although 50% effectiveness is far below the greater than 90% real-world protection of COVID-19 vaccines made with messenger RNA (mRNA), it may still be good enough to curb the disease’s spread within Brazil; vaccines with that level of efficacy in a clinical trial qualify for emergency use in many places and meet the World Health Organization’s threshold, as well.
It’s also not clear how well the mRNA vaccines protect against the P.1 variant; their clinical tests happened before it was circulating or in places with little of the variant. Moreover, CoronaVac likely offers far greater protection against severe disease, hospitalization, and death than against milder cases of COVID-19. That was seen in two dose efficacy trials conducted in Brazil and other countries and is typical of COVID-19 vaccines. But the new study has not yet collected enough severe cases to calculate effectiveness, Croda says.
The study’s preliminary results, not yet peer reviewed, were posted to a preprint server yesterday and are the first to assess the effectiveness of the vaccine made by Sinovac Biotech in an area flooded with the P.1 variant. CoronaVac contains inactivated whole copies of SARS-CoV-2, in contrast to many other COVID-19 vaccines, including the mRNA vaccines, which just present the spike protein of the virus to the immune system.
The origin of the P.1 variant was traced to Brazil in January, and the strain has quickly spread to the rest of the world. Laboratory studies that assess whether vaccine-induced antibodies can neutralize SARS-CoV-2’s infectivity have raised concerns that the variant could escape the immune protection conferred by vaccines. The mutated virus is likely to be driving a recent COVID-19 resurgence in Brazil—the country currently has up to 60,000 new cases per day. COVID-19 has killed more than 340,000 Brazilians.
The CoronaVac study involved medical data from 67,718 health care workers from Manaus, a city in the Amazon region that is the epicenter of the P.1 variant. The mutant virus now accounts for 75% of all positive test results in the city, where the health system is collapsing because of COVID-19.
To estimate CoronaVac’s effectiveness, the researchers focused on 2656 health workers who had taken polymerase chain reaction (PCR) tests for SARS-CoV-2 infections beginning in January, with the initial rollout of the vaccine, through last week. The scientists identified 786 people with apparent COVID-19 symptoms, whom they divided into two groups of 393 each: those who tested positive and negative for the virus. Then, the researchers checked the proportion of vaccinated and unvaccinated people in both groups. In the positive group, 18.6% were vaccinated; in the negative group, the proportion was 24.4%. Using the unvaccinated people as a reference, the researchers calculated the risk of infection by SARS-CoV-2 14 days after the first dose.
The 49.6% real-world effectiveness is similar to the vaccine’s efficacy of 50.34% against symptomatic COVID-19 after both doses, found in a phase 3 clinical trial conducted in Brazil by the Butantan Institute, a state-owned research institute and vaccinemaker. “This is not a coincidence,” says epidemiologist Ricardo Palácios, who ran the vaccine tests at the institution, which is now producing CoronaVac under an agreement with Sinovac. “This is an independent confirmation that the vaccine is efficient in a scenario of a new variant.”
Epidemiologist Eric Feigl-Ding at the Federation of American Scientists, however, cautions that the new study did not sequence SARS-CoV-2 in the people with positive PCR tests to make sure their infections were caused by the P.1 variant. The authors’ conclusion that the vaccine protects against the variant rests on assuming it makes up most of the positive cases, he notes.
On the other hand, Feigl-Ding says, measuring vaccine effectiveness in Brazil may produce artificially low results because there is a high risk that people have some immunity because of previous contact with the virus. “This is a natural property of doing a trial in a highly previously infected population,” he says. This could also explain why the CoronaVac clinical trial in Brazil showed lower efficacy numbers (50%) than in other countries such as Turkey (83.5%) and Indonesia (65%).
CoronaVac may prove better in a general population, as the new trial’s data come from health care workers who are highly exposed to the virus, points out immunopathologist Bruno Filardi at the Brazil Cancer Institute. “Probably the effectiveness will be higher than the preliminary study is showing,” he says. In addition to Brazil, CoronaVac has been authorized and used in China, Chile, Bolivia, Mexico, Turkey, and Indonesia.
Croda and his colleagues will continue to analyze the effectiveness of various COVID-19 vaccines against P.1 and other variants with larger groups of people. In the next 2 weeks, they plan to look at data from Sao Pãulo, where more than 7 million people have been vaccinated with CoronaVac or AstraZeneca’s vaccine. That work is a top priority, according to infectious disease expert Jason Andrews at Stanford University, who works with the Brazilian research team and is a co-author on the preprint. “It will be critical to detect when vaccines are no longer effective against emerging variants,” he says. “Which is a question of when rather than if.”
The vaccine developed by Sinovac Biotech Ltd. was effective in controlling Covid-19 in a mass-inoculation study in a small Brazilian town after 75 per cent of adults were covered with a second shot, preliminary numbers show.
PHOTO: AFP
[SAO PAULO] The vaccine developed by Sinovac Biotech Ltd. was effective in controlling Covid-19 in a mass-inoculation study in a small Brazilian town after 75 per cent of adults were covered with a second shot, preliminary numbers show.
The study carried out by the Sao Paulo state government in the small town of Serrana - population 45,000 - may offer clues for other developing nations on how much of the public needs to be vaccinated in order to begin moving past the pandemic that continues to wreak havoc in Latin America and beyond.
While infection rates improved after first doses were administered, Covid-19 wasn't properly controlled in the town until after a second shot was given. A complete study will be published soon.
The study was led by the Butantan Institute, which produces Sinovac's so-called CoronaVac in Brazil. Almost two-thirds of Serrana's inhabitants got the vaccine between February and April with another third ineligible to receive the shot if they were under 18 years old or pregnant. About 95 per cent of the targeted adult population received the required two doses in the study.
"This is the first study of its kind in the world," Dimas Covas, Butantan's director, said at a press conference Monday. "This is primary data on the effects of vaccination in a population that will help authorities develop public policies." While neighboring cities were being hit hard by the pandemic, Serrana saw deaths fall by 95 per cent in the five weeks right after the mass-vaccination was completed. Symptomatic cases dropped by 80 per cent and hospitalizations decreased by 86 per cent.
"Now we can say that it's possible to control the pandemic with vaccines," Ricardo Palacios, research director at Butantan said, adding that Covid-19 numbers also fell for children. "This shows that it isn't necessary to vaccinate children to open schools."
No severe side effects from the vaccine were reported and there were no Covid-related deaths among participants 14 days after the second dose was applied. The area around Serrana, some 315 kilometers (195 miles) from Sao Paulo, was overrun by the P1 variant during the study, reaffirming the jab's effectiveness against the strain first found in Brazil, Palacios said.
Sinovac's vaccine is being used widely in the developing world including Chile, Turkey, Indonesia and the Philippines.
The findings also underline the importance of people returning for a second shot. In Brazil, some 66 million vaccines have been administered, covering 21.4 per cent of the population with a single dose. About 10.5 per cent of the country is now considered to be fully inoculated, according to the Bloomberg vaccine tracker.
Brazil says CoronaVac has an efficacy rate just over 50 percent, much lower than previously announced. More than 380 million doses have already been ordered.
Inspecting vials containing the CoronaVac vaccine, made by the Chinese company Sinovac, at the Butantan Institute in São Paulo, Brazil. Credit...Amanda Perobelli/Reuters
Scientists in Brazil have downgraded the efficacy of a Chinese coronavirus vaccine that they hailed as a major triumph last week, diminishing hopes for a shot that could be quickly produced and easily distributed to help the developing world.
Officials at the Butantan Institute in São Paulo said on Tuesday that a trial conducted in Brazil showed that the CoronaVac vaccine, made by the Beijing-based company Sinovac, had an efficacy rate just over 50 percent. That rate, slightly above the benchmark that the World Health Organization has said would make a vaccine effective for general use, was far below the 78 percent level announced last week.
The implications could be significant for a vaccine that is crucial to China’s global health diplomacy. At least 10 countries have ordered more than 380 million doses of CoronaVac, though regulatory agencies have yet to fully approve it.
A senior official in Hong Kong, a special administrative region of China that had already ordered CoronaVac, said on Wednesday that an advisory panel would strictly review the vaccine based on clinical trial data before it was rolled out there.
“Those countries that have ordered the Chinese-made vaccines are probably going to question the usefulness of these vaccines,” said Yanzhong Huang, a senior fellow for global health at the Council on Foreign Relations and an expert on health care in China.
“Countries with opposition parties might use this to challenge the decision made by the incumbent government, and that will likely have domestic political implications in these countries,” Mr. Huang said.
Sinovac did not respond to multiple requests for comment.
For months, Chinese officials had said the vaccines made by Sinovac and Sinopharm, a state-owned vaccine maker, would be important tools for fighting the pandemic in poorer countries that do not have extensive health care infrastructures. Unlike the vaccines made by the American drugmakers Pfizer and Moderna, they do not need to be frozen.
YOUR CORONAVIRUS TRACKER: We’ll send you the latest data for places you care about each day.
The Oxford-AstraZeneca and Johnson & Johnson vaccines, which can be refrigerated and are more effective than their Chinese counterparts, could provide an alternative. But it is now unclear if the governments that have bought CoronaVac can scrap their deals and turn to others.
CoronaVac, unlike some of the other vaccines, relies on older technology that uses chemicals to weaken or kill the virus, which is then put into a vaccine to spark antibodies in the recipient. But the process of killing the virus can weaken a vaccine’s potency, resulting in an immune response that could be shorter or less effective.
The lower efficacy announced Tuesday would mean it would take longer for countries that used CoronaVac’s vaccine to reach “herd immunity,” the point at which enough people are resistant to the virus — roughly 70 percent, many scientists have said — that it is vanquished in a population. By contrast, the vaccines made by Moderna and Pfizer-BioNTech have been shown to have an efficacy rate of about 95 percent.
“This was one of the reasons the Americans and Europeans didn’t go with this older technology,” said John Moore, a vaccine expert at Cornell University. “A well-maintained Ford Model T would probably get you from Wuhan to Beijing, but personally I would prefer a Tesla.”
Brazil’s health regulatory agency, Anvisa, is reviewing data from the trial, which relied on volunteers who are health care professionals. If Anvisa approves emergency use of CoronaVac, officials hope to start giving out shots in Brazil late this month. It has roughly 10.8 million doses of CoronaVac on hand. Last week, Brazil’s health minister, Eduardo Pazuello, said the government intended to buy 100 million doses of CoronaVac.
Natalia Pasternak, a microbiologist and the president of Instituto Questão de Ciência, a Brazilian nongovernmental organization, told reporters on Tuesday that the results of the trial meant it would not be a panacea.
“It is not the best vaccine in the world,” she said at the news conference during which the efficacy rate was disclosed. But she called it a “perfectly acceptable vaccine” that would lead to fewer patients developing serious cases or dying from the virus.
Dimas Covas, the director of the Butantan Institute, called the vaccine an “excellent” tool “waiting to be used in a country where currently 1,000 people are dying per day.”
Many of the countries that have ordered CoronaVac are relatively poor, desperate to halt the pandemic and protect their populations.
Indonesia, for example, has ordered 125.5 million CoronaVac doses. The country has reported nearly 850,000 coronavirus cases and nearly 25,000 deaths, the highest numbers in Southeast Asia.
On Wednesday morning, its president, Joko Widodo, was injected with CoronaVac on live television, kicking off a national vaccination program. “Covid vaccination is important for us to break the chain of transmission of this coronavirus and provide health protection for all of us,” Mr. Joko said after getting his shot.
Sulfikar Amir, an Indonesian associate professor of disaster sociology at Nanyang Technological University in Singapore, said the latest results from Brazil were a cause for concern.
“Why doesn’t Indonesia wait for a better vaccine?” he asked. “My impression is that this is rushed and forced.”
To its comparative advantage, Sinovac has immense manufacturing capacity. The company has said it can make 600 million doses this year.
In China, the weaker efficacy data from Brazil could be a setback for the country’s biotech ambitions. It had pinned its hopes on making a Covid-19 vaccine that would burnish its credentials as a global scientific power.
The tepid results could also be problematic for Chinese officials, given that they had touted the efficacy of the vaccines made by Sinovac and Sinopharm. Even though the vaccines had not received regulatory approval, and data from late-stage trials had not been made public, Beijing gave them to thousands of Chinese people under an emergency use policy; it plans to vaccinate 50 million people by the middle of next month.
State media in China played down the news from Brazil. Global Times, a state-owned nationalist tabloid, ran a headline that said the Sinovac vaccine was “100 percent effective in preventing severe cases, could reduce hospitalizations by 80 percent.”
The new data could heighten skepticism among people around the world who are already wary of Chinese-made vaccines, given that the country has a history of vaccine quality scandals. A study from the Chinese University of Hong Kong found that just 37.2 percent of respondents in Hong Kong were willing to be vaccinated.
Scientists had already raised questions about the piecemeal way in which efficacy data about the Chinese vaccines had been released. Indonesia said on Monday that its interim analysis found CoronaVac to have an efficacy rate of 65.3 percent. Last month, Turkey said it had an efficacy rate of 91.25 percent, but that was based on preliminary results from a small clinical trial.
The vaccine had long taken on a political dimension in Brazil. President Jair Bolsonaro had spoken derisively about CoronaVac, fueling an growing anti-vaccination movement in the country, where more than 200,000 people have died from Covid-19. The vaccine had been championed by São Paulo’s governor, João Doria, who is widely expected to run for president in 2022 and is among Mr. Bolsonaro’s most vocal critics.
In Brazil, officials say the higher efficacy rate previously announced for CoronaVac pertained to the protection it offered against developing Covid-19 symptoms significant enough to require treatment. While officials had asserted last week that the vaccine provided absolute protection against moderate to severe symptoms, they had not disclosed another group who had “very mild” infections despite having been vaccinated.
Denise Garrett, a Brazilian-American epidemiologist and vaccine expert, said there was no reason to doubt CoronaVac’s safety, adding that the data presented so far suggested it would provide a satisfactory level of protection. But Dr. Garrett said the vague and sometimes misleading manner in which information about the vaccine had been made public could shake people’s confidence in its reliability and fuel the political battle over the vaccine.
“The lack of transparency really damages people’s trust,” she said. “They’ve just reinforced the narrative that this vaccine is not good.”
Reporting was contributed by Manuela Andreoni, Letícia Casado, Richard C. Paddock and Muktita Suhartono. Elsie Chen contributed research.
Ernesto Londoño is the Brazil bureau chief, based in Rio de Janeiro. He was previously an editorial writer and, before joining The Times in 2014, reported for The Washington Post. @londonoe•Facebook
A version of this article appears in print on Jan. 14, 2021, Section A, Page 6 of the New York edition with the headline: Disappointing Results Pose a Vaccine Setback. Order Reprints | Today’s Paper | Subscribe
