The study of the aggressive strain Covid-19 in Brazil suggests limits of the China vaccine

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

While the sample size of the study was small and required further testing, the fact that all eight samples produced the same result is a “notable phenomenon”, suggesting that CoronaVac is less able to counteract P.1 infections than the virus versions found. previously 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-backed CGTN broadcaster Sinovac released this week, Executive Director Yin Weidong said that if necessary, it would take less time to develop a variant vaccine than from scratch.

“It’s like this thief I’ve already caught,” he said. Even if it is mutant, we can fully use 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 half a year after vaccination with CoronaVac, adding that the company is still researching how long the protection lasts and will publish this data soon. He said the company is also looking into the effectiveness of providing additional booster photos.

As the P.1 strain has spread rapidly in Brazil and 20 other countries, there have been growing concerns about how well Covid-19 vaccines will work against the variant and many others that appear in the largest country in Latin America.

CoronaVac, which is expected to be launched largely in 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 around the world have caused the worst pandemic, public health experts say Brazil is facing its darkest days, with the daily death toll expected to surpass that of the US, and to reach a new peak in the coming weeks.

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

The variant, which first appeared in the Amazonian city of Manaus at the end of last year, is 1.4 to 2.2 times more contagious than the virus versions previously found in Brazil and 25% to 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 completed intensive care beds or are operating at almost full capacity, while a lack of oxygen has recently led to dozens of patients suffocating to death in the Amazon. Prosecutors investigated reports that intubated patients in the region were tied to their beds due to a shortage of sedatives.

Public health experts say Brazil is now facing a race against time 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 in the country, although P.1 is thought to be the most worrying.

After President Jair Bolsonaro spent months reducing the pandemic and eliminating a vaccine supply agreement with Pfizer Inc. last year, the country relied heavily on CoronaVac since launching its immunization campaign in January. The Chinese vaccine, which was developed in partnership with the state of São Paulo, accounts for more than 70% of Covid-19 vaccines administered in Brazil.

Although it has an efficacy rate of about 50%, one of the lowest rates for any existing Covid-19 vaccine, CoronaVac has prevented 100% of moderate and severe cases of the disease, late-stage clinical trials in Brazil have shown.

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

However, infectious disease specialists, including the study’s authors, warned that further broader studies should be conducted to show how well CoronaVac works against new variants and whether it can prevent people from getting P.1.

The study itself was not designed to specifically test CoronaVac, but to test how antibodies created either by vaccination or by 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 was not involved in the study. “Preliminary results need to be published very carefully,” he said.

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

Mr Bolsonaro, a staunch critic of China, told his supporters late last year that CoronaVac could cause them to die or suffer disabilities without providing any evidence. He instead supported the antimalarial drug hydroxychloroquine and, more recently, the use of an experimental nasal spray to treat patients with Covid-19.

Public health specialists have largely blamed Mr Bolsonaro’s administration for the death toll in the country. While many state governors imposed restrictions on keeping Brazilians at home, the president encouraged people to break those rules and rallied against the face masks.

“Stop fussing and complaining,” former Bolsonaro, a former army captain, said this week, in what some experts said was also an attempt to divert media attention from a growing corruption scandal. involves his son. “How long will you keep crying about this?”

—Chao Deng of Taipei contributed to this article.

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