Synovac Biotech’s experimental COVID-19 vaccine caused Coronavac to develop rapid immunity but antibody levels were lower than those recovered from the disease, preliminary trial results showed Wednesday.
While early mid-stage tests were not designed to assess coronavirus efficacy, the researchers said it could provide adequate protection based on their experience with other vaccines and prenatal study data with macaques.
This month, U.S. Drugmakers Pfizer and Moderna, as well as Russia’s Sputnik VN, follow up on these encouraging announcements that their experimental vaccine was more than 90 percent effective, based on interim data from large, late-phase trials.
Coronavac and four other experimental vaccines developed in China are currently undergoing late-stage trials to determine their effectiveness in preventing Covid-19.
The synovial findings, published in the medical journal The Lancet Peer-Review Paper on Infectious Diseases, come from the results of the first phase and second phase clinical trials in China involving more than 700 participants.
“Our findings show that Coronavac is able to elicit a rapid antibody response within four weeks of vaccination by administering two doses of the vaccine at 14-day intervals,” said Xu Fengkai of the Jiangsu Provincial Center for Disease Control and Prevention. One of the authors of the paper.
Coronavac is one of three experimental COVID-19 vaccines that China is using to inoculate hundreds of thousands of people under its emergency use program. [File: Thomas Peter/Reuters]
“We believe this makes the vaccine suitable for emergency use during an epidemic,” Xu said in a statement published with the paper.
Among the limitations of the second phase trial, the researchers noted that only healthy adults were involved and that individuals in COVID-19 susceptibility groups, including those 60 years of age or older with other underlying diseases, were not included in the study. .
It also did not evaluate the T-cell response, which they said would be part of the third phase of testing in Brazil. The third phase trial is also underway in Indonesia and Brazil, which have recorded the highest number of coronavirus cases in the world after the United States and India.
The findings of that large, late-stage study will be crucial in determining whether the immune response generated by coronavirus was sufficient to protect people from coronavirus infection, scientists said.
Naur Bar-Zive of Johns Hopkins University, who was not involved in the study, said the results must be interpreted with caution until the third phase results are published.
“But even then, after the end of the Phase III trial and the licensing, we must be prudent.”
‘Attractive option’
Coronavac is one of three experimental COVID-19 vaccines that China is using to inoculate hundreds of thousands of people under its emergency use program.
According to peer-reviewed papers, two other vaccines in China’s emergency program were developed by organizations affiliated with both synopharms, and another vaccine from Cancino Biologics also gave an immune response in early and mid-stage trials.
Synovac researcher Gang Zheng, who was involved in the Coronavac study, said the vaccine could be an attractive option because it can be stored at 2 to 8 degrees Celsius (36 ° – 46 ° F) in normal fridge temperatures and will remain stable. Three years.
“It will provide some benefits for distribution in regions where the reach of refrigeration is challenging,” Gang said.
Synovac is in the late stages, with large-scale trials of its pilot vaccines in Brazil, Indonesia and Turkey. [File: Diego Vara/Reuters]
In contrast, vaccines developed by Pfizer / Bioentech and Moderna use a new technology called synthetic messenger RNA (mRNA) to activate the immune system against the virus and require cold storage.
The Pfizer vaccine must be stored and transported in -70C, although it can be kept in a refrigerator for up to five days, or in thermal shipping boxes for up to 15 days. Moderna candidate expects to remain stable in normal fridge temperature for 30 days but needs to keep it at -20C for storage for six months.
Coronavac is also being considered for inoculation by Brazil and Indonesia in the coming months.
Indonesia has sought emergency approval to launch a mass vaccination campaign by the end of the year and is preparing to use vaccines produced by Sinowak and China’s Sinofarm in the early stages of the campaign.
Brazil’s Sao Paulo will begin importing the first of China’s 46 million doses of the Synovac vaccine against COVID-19 this week and plans to roll out the Coronavac in early January.
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