Aggressive Covid-19 strain study in Brazil suggests the limits of Chinese vaccines

Researchers in Brazil, the United Kingdom, and the United States have found that the plasma of eight people vaccinated with CoronaVac five months ago “could not be efficiently neutralized.” A new Amazon stock called P.1.. This study does not show whether CoronaVac can prevent the outbreak of disease caused by variants, which is one of the main goals of vaccination campaigns.

The sample size of the study is small and needs further testing, but the fact that all eight samples produced the same results is a “notable phenomenon”, and CoronaVac is more P. It suggests that the ability to stop the infection of 1 is low. Brazil is one of the authors of the study, said William de Souza of the University of Sao Paulo in Ribeirao Preto.

Sinovac, a Chinese company that manufactures CoronaVac, did not respond to requests for comment. In an interview with Sinovac’s state-run broadcaster CGTN this week, CEO Yin Weidong said it would take less time to develop a variant vaccine from scratch, if needed.

“It’s like having this thief we’ve already caught,” he said. “Even if it is mutated, we can take full advantage of our current research and production capacity to effectively develop new mutant vaccines.”

In an interview, Weidong said Sinovac found that human antibodies were reduced six months after CoronaVac vaccination, adding that the company is still investigating the duration of protection and will release the data shortly. He also said the company is investigating the effectiveness of offering additional booster shots.

How well the existing Covid-19 vaccine is against the variants and many other vaccines emerging in Latin America’s largest country, as the P.1 strain spread rapidly to Brazil and more than 20 other countries. There is growing concern about whether it will work.

CoronaVac, Deployed in most parts of Latin America And other developing countries in Africa and Asia Brazil’s best hope to defeat the pandemic In the short term, public health experts said.

The disease killed more than 260,000 people in Brazil. While other countries in the world are driving the worst of the pandemic, public health experts say Brazil is in the darkest day ever, with daily deaths surpassing the United States and going forward. It is expected 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 devastated town in the state of São Paulo, this week. A recent study showed that more than 90% of Covid-19 patients in a packed hospital in Araraquara were positive for the P.1 strain.

According to a recent study, 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 the virus version previously found in Brazil, 25% to 61% more. It has the ability to reinfect a person. ..

The effect has already been felt nationwide. Most state hospitals are already short of ICU beds or are almost at full capacity, Oxygen deficiency recently led to scores for choking patients Die in the Amazon. Prosecutors investigated reports that intubated patients in the area were tied to their beds following a sedative deficiency.

Public health experts say Brazil is currently facing a battle with time to vaccinate its population before the emergence of other potentially aggressive new Covid-19 variants. I did. Researchers widely believe that P.1 is the most worried, but estimates that hundreds of diseases are already prevalent in the country.

The country has been heavily dependent on Coronabac since it launched its vaccination campaign in January after President Jair Bolsonaro curtailed the pandemic and broke the vaccine supply contract with Pfizer last year. The Chinese vaccine, developed in collaboration with the State of São Paulo, accounts for more than 70% of Covid-19 shots given in Brazil.

Although effective at about 50%, one of the lowest rates of existing Covid-19 vaccines, CoronaVac has 100% prevented cases of moderate to severe illness in late-stage clinical trials in Brazil. Showed.

The P.1 study, published March 1, also relies on researchers at the University of Oxford and the University of Washington School of Medicine to first show how CoronaVac reacts to P.1.

However, infectious disease experts, including the authors of the study, show how well CoronaVac works for new variants and whether it can still prevent people from getting sick on P.1. It warns that other, more extensive studies need to be undertaken in order to do so.

The study itself was not designed to specifically test CoronaVac, but antibodies produced by vaccination or previous infections from other versions of Covid-19 have been added to the new P.1 strain. It was designed to test how it reacts when faced.

“This is an exploratory study, with a flashing yellow light, not a red light,” said Carlos Fortaleza, an epidemiologist at the State University of São Paulo who was not involved in the study. “Preliminary results must be published with great care,” he said.

Some scientists have expressed concern that such studies may discourage people from being vaccinated against coronabac.

Bolsonaro, a fierce critic in China, told supporters late last year that Corona Bac could kill or hurt them without providing evidence. He instead defended the antimalarial drug hydroxychloroquine and recently favored the use of nasal drops to treat Covid-19 patients.

Public health experts have blamed the Bolsonaro administration for the country’s surge in deaths. Many governors imposed restrictions to keep Brazilians home, but the president encouraged people to break those rules and opposed face masks.

“Stop the turmoil and whining,” said Bolsonaro, a fiery former Army captain, this week. Some experts said it was also an attempt to distract the press from the spread of corruption scandals involving his son. “How long will you keep crying?”

— Chao Deng of Taipei contributed to this article.

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