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

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

Although the sample size of the study was small and requires further testing, the fact that all eight samples produced the same result is a “remarkable phenomenon,” suggesting that CoronaVac is less able to frustrate P infections. .1 that versions of the virus previously found in Brazil, said William de Souza, of the University of São Paulo, in Ribeirão Prêto, one of the study’s authors.

Sinovac, the Chinese company that produces CoronaVac, did not respond to requests for comment. In an interview with state broadcaster CGTN that Sinovac launched this week, CEO Yin Weidong said that if necessary, less time would be needed to develop a vaccine for variants than from scratch.

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

Weidong said in the interview that Sinovac had found the fall of antibodies from a person half a year after vaccination with CoronaVac, adding that the firm was still investigating how long the protection would last and would release that data soon. He said the firm is also studying the effectiveness of offering additional reinforcement shots.

As the P.1 strain has spread rapidly throughout Brazil and more than 20 countries, concerns have grown about the operation of existing Covid-19 vaccines against the variant and the many others that appear in the largest country in the world. ‘Latin America.

CoronaVac, which is expected to be deployed in 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 experts said.

The disease has killed more than 260,000 people in Brazil. While other countries in the world have left behind the worst of the pandemic, public health experts say Brazil is facing its darkest days so far, as the daily death toll is expected to exceed that of the United States and reach a new high in the coming weeks.

“This will be the greatest humanitarian tragedy in the history of Brazil,” warned this week Edinho Silva, the mayor of Araraquara, a city affected by the state of São Paulo. A recent study showed that more than 90% of patients with Covid-19 in Araraquara hospitals tested positive for strain P.1.

The variant, which first emerged in the Amazonian city of Manaus late last year, is between 1.4 and 2.2 times more contagious than previously found versions of the virus in Brazil and a 25 61% more able to reinfect people, according to a recent study.

Its effects are already being felt across the country. Hospitals in most states have already run out of ICU beds or are operating at almost full capacity, while oxygen shortages recently led to the death of suffocators in the Amazon. Prosecutors have investigated reports indicating that intubated patients in the region were bedridden after a shortage of sedatives.

Public health experts said Brazil is now facing a race against the clock to vaccinate its population before other potentially aggressive variants of Covid-19 appear. Researchers estimate that there are already hundreds of strains of the disease circulating across the country, although P.1 is believed to be the most worrisome.

After President Jair Bolsonaro spent months minimizing the pandemic and eliminating a vaccine supply agreement with Pfizer Inc. last year, the country has relied heavily on CoronaVac since it began its vaccination campaign in January. The Chinese vaccine, which has been developed in collaboration with the state of São Paulo, accounts for more than 70% of Covid-19 shots administered in Brazil.

Despite having an efficacy rate of around 50%, one of the lowest rates for any existing Covid-19 vaccine, CoronaVac prevented 100% of moderate and severe cases of the disease, according to clinical studies. in the final phase in Brazil.

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

However, specialists in infectious diseases, including the study’s authors, have warned that further, larger studies should be conducted to show the extent to which CoronaVac works against new variants and whether it can still prevent people from getting sick. at P.1.

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

“It’s an exploratory study, a flashing yellow light, but not a red one,” said Carlos Fortaleza, an epidemiologist at São Paulo State University who did not participate in the study. “Preliminary results need to be published very carefully,” he said.

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

Bolsonaro, a fierce Chinese critic, told his followers late last year that CoronaVac could cause his death or disability, without providing evidence. Instead, he has advocated the hydroxychloroquine antimalarial drug and, more recently, the use of an experimental nasal spray to treat patients with Covid-19.

Public health specialists have largely blamed the administration of Mr. Bolsonaro of the increase in the number of deaths in the country. While many state governors have imposed restrictions on keeping Brazilians at home, the president has encouraged people to break those rules and rallied against face masks.

“Stop scolding and complaining,” Mr Bolsonaro, a former army captain, said this week in what some experts said was also an attempt to divert the attention of the press from a growing corruption scandal involving his son. “How long will you keep crying for this?”

—Chao Deng in Taipei contributed to this article.

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