Good reputation and common interest in fighting the pandemic

Good reputation and common interest in fighting the pandemic

Good reputation and common interest in fighting the pandemic quickly brought Butantan and Sinovac together, explains clinical director of the chinese drugmaker

by Butantan Team

Published: October 27, 2021

The main reasons that led Chinese pharmaceutical Sinovac to become a partner of Butantan were the institute’s reputation and the shared value: to fight the pandemic as soon as possible. This is how Sinovac’s clinical director, Zeng Gang, on a visit to Brazil, explains why the Chinese company prioritized Butantan among several commercial partners interested in the joint production of a vaccine against Covid-19 in 2020.

Zeng recalls that when the pandemic emerged, Sinovac thought hard about whether it would direct efforts to the development of an immunizing agent against SARS-CoV-2. That’s because in 2003, during the SARS (Severe Acute Respiratory Syndrome) outbreak in Asia, the company had invested in a vaccine that ended up not being used, as the disease was soon brought under control. Despite the negative track record, executives chose to take the risk again in 2020.

“There was a concern that the pandemic would continue and there would not be a vaccine. To save lives, we decided to research and produce an immunizing agent to fight SARS-CoV-2”, completes the clinical director

Starting with the vaccine studied for the 2003 coronavirus outbreak, Chinese scientists dedicated themselves to adapting to the new pathogen. Phase one and two clinical trials took place quickly in China and the emergency use of the product in the country was approved in July 2020. CoronaVac’s inactivated virus technique, which is used in vaccines such as polio, hepatitis A and influenza, helped to streamline the process.

“It was a very mature technology that had worked for the last century. After all, we’ve had inactivated vaccines for many, many years,” says Zeng.

“To be honest, this must be the safest vaccine in the world in terms of serious and common adverse events.”

With its safety and ability to induce an immune response approved, it was time to analyze the vaccine’s effectiveness with phase three clinical trials – when an immunizer is tested on a large number of people. This step cannot be done in China, as the pandemic was under control there in mid-2020. In addition, until February this year, the National Health Surveillance Agency (Anvisa) required, for the granting of authorization for emergency use of a new immunization, that phase three studies were conducted in Brazil.

“In two or three weeks we created an agreement with Butantan. Once this agreement was closed, Butantan was responsible for carrying out the phase three clinical trials and it was very fast. After three weeks we had Anvisa’s approval and, after another two weeks, we started to immunize the volunteers”, says Zeng, noting that the relationship between Sinovac and Butantan is good and involves trust on both sides.

Phase 3 clinical trials in Brazil – carried out with healthcare professionals, the public most exposed to Covid-19 – showed an overall efficacy of 50.7% of CoronaVac in the 14-day interval between the two doses, and of 62, 3% when the range is 21 to 28 days. But most important, according to Zeng, is the vaccine’s performance in protecting against hospitalizations and deaths.

“This is what has to be remembered: serious cases have dropped a lot, thanks also to CoronaVac.”

Vaccine in children and continuation of the partnership

CoronaVac is the most used vaccine on the planet against Covid-19, with more than two billion doses manufactured, which represents 24% of the world’s total production. This number, coupled with the high security profile characteristic of the inactivated virus technology, is one of the reasons Zeng advocates the use of CoronaVac in children as well.

“We found that immunity in the pediatric population is three to five times greater than in the adult. In China, we already have 100,000 doses given to this audience. In Chile, mass vaccination of children has started. We also have other countries like Indonesia, Cambodia and Malaysia that have approved pediatric use”, points out the clinical director.

According to him, after six months, the seroconversion of children continues at around 80%, and it is possible that they do not even need a booster dose.

The vaccine from Butantan and Sinovac has also shown good results in the booster dose.

“Six months after the booster dose in seniors and frontline professionals, antibodies were higher than a month after the second dose,” says Zeng

Butantan and Sinovac plan to continue the partnership and produce second-generation vaccines. To do this, the researchers will monitor the effects of the booster dose and how effective it will be.

“There will always be new scientific questions to be answered in the near future, which will give us new opportunities for collaboration.”

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