Study of aggressive Covid-19 strain in Brazil suggests vaccination limits in China

Researchers from Brazil, the United Kingdom and the United States have found that the plasma of eight people who were vaccinated with CoronaVac five months ago could not effectively neutralize the new Amazon strain, called P.1. The study did not show whether CoronaVac can still prevent people from getting the variant, one of the main objectives of vaccination campaigns.

While the sample size of the study was small and needs to be further tested, the fact that all eight samples yield the same result is a ‘significant phenomenon’, suggesting that CoronaVac is less able to stop P.1 infections than versions. of the virus earlier in William de Souza, of the University of São Paulo in Ribeirão Prêto, one of the authors of the study, said in Brazil.

Sinovac, the Chinese firm that manufactures CoronaVac, did not respond to requests for comment. In an interview with state broadcaster CGTN that Sinovac announced this week, CEO Yin Weidong said that, if necessary, it would take less time to develop a vaccine for the variants than from scratch.

“It’s like there’s the thief we’re already caught,” he said. “Even though it is mutating, we can fully utilize the current research and production capacity to effectively develop a vaccine for the new variant.”

Mr. Weidong said in the interview that Sinovac found that a person’s antibodies drop six months after vaccination with CoronaVac, adding that the firm is still investigating how long protection lasts and will release this data soon. He said the firm is also investigating the effectiveness of offering additional boost shots.

As the P.1 strain spread rapidly in Brazil and in more than 20 other countries, concerns arose about how well existing Covid-19 vaccines would be against the variant and the many others in Latin America’s largest country. work.

CoronaVac, which is expected to spread across much of Latin America and other developing countries in Africa and Asia, is Brazil’s best hope of overcoming the pandemic in the short term, public health specialists said.

The disease has killed more than 260,000 people in Brazil. While other countries around the world are facing the worst pandemic, healthcare specialists say Brazil is still facing its darkest days, and the daily death toll is expected to surpass that of the US and in the coming weeks a reaches new high point.

“This is going to be the biggest humanitarian tragedy in the history of Brazil,” Edinho Silva, the mayor of Araraquara, a hit city in the state of São Paulo, warned this week. A recent study showed that more than 90% of the Covid-19 patients in Araraquara’s packaged hospitals tested positive for the P.1 strain.

The variant, which first appeared in the Amazon city of Manaus at the end of last year, is 1.4 to 2.2 times more contagious than versions of the virus found earlier in Brazil, and 25% to 61% more able to re-infect humans, according to a recent study.

The consequences are already being felt across the country. Hospitals in most states have already run out of ICU beds, or they are operating at almost full capacity, while oxygen deficiencies have recently led to many patients suffocating in the Amazon. Prosecutors are investigating reports that integrated patients in the region have been tied to their beds following a shortage of sedatives.

Public health specialists have said that Brazil is now facing a race to vaccinate its population before other potentially aggressive new Covid-19 variants appear. Researchers estimate that there are already hundreds of strains of the disease circulating in the country, although P.1 is widely regarded as the most worrying.

After President Jair Bolsonaro put an end to the pandemic for months and last year reached an agreement with Pfizer Inc. had the country relied heavily on CoronaVac since its vaccination campaign began in January. The Chinese vaccine, developed in partnership with the state of São Paulo, accounts for more than 70% of the Covid-19 shots administered in Brazil.

Despite an efficacy rate of approximately 50%, one of the lowest doses for any existing Covid-19 vaccine, CoronaVac prevented 100% of moderate and severe cases of the disease, late-stage clinical trials in Brazil showed.

The P.1 study, published March 1, which also relied on researchers from Oxford University and the Washington University School of Medicine, provides the first indications of how CoronaVac may respond to P.1.

However, specialists in infectious diseases, including the study authors, have warned that other broader studies need to be conducted to show how well CoronaVac works against new variants, and whether it can still prevent people from getting sick from P.1.

The study itself is not designed to specifically test CoronaVac, but to test how antibodies created by vaccination or by previous infections from other versions of Covid-19 react when dealing with the new P.1 strain. .

“It’s an exploratory study, a flickering yellow light, but not a red one,” said Carlos Fortaleza, an epidemiologist at São Paulo State University who was not involved in the study. “Preliminary results must be announced with great care,” he said.

Some scientists have expressed concern that such studies could deter people from being vaccinated with CoronaVac, which has been heavily criticized by the president himself.

Mr. Bolsonaro, a fierce critic in China, told his supporters late last year that CoronaVac could cause them to die or be disabled without providing evidence. He rather fought the antimalarial drug hydroxychloroquine, and more recently the use of an experimental nasal spray to treat Covid-19 patients.

Specialists in public health have the administration of mr. Bolsonaro was largely blamed for the rising death toll in the country. While many state governors imposed restrictions on keeping Brazilians at home, the president encouraged people to break the rules and rallied against face masks.

“Stop yelling and whining,” he said. Bolsonaro, an ardent former army captain, said this week. According to some experts, it was also an attempt to divert the attention of the press from a growing corruption scandal involving his son. “How long are you going to cry about it?”

—Chao Deng in Taipei contributed to this article.

Write to Samantha Pearson at [email protected] and Luciana Magalhaes at [email protected]