China Covid Vaccine Induces Rapid Immune Response Within 4 Weeks: Study


A man works in a laboratory at Chinese vaccine manufacturer Sinovac Biotech developing an experimental vaccine.


Sinovac Biotech’s CoronaVac experimental COVID-19 vaccine triggered a rapid immune response, but the amount of antibodies produced was lower than that of people who had recovered from the disease. This was shown by preliminary test results on Wednesday.

While the early-to-mid-stage studies were not designed to evaluate CoronaVac’s effectiveness, the researchers said that based on their experience with other vaccines and data from preclinical studies with macaques, it may provide adequate protection.

The study follows positive news this month from US drug makers Pfizer and Moderna, as well as Russia, showing that their experimental vaccines were over 90% effective based on interim data from large, late-stage studies.

CoronaVac and four other experimental vaccines developed in China are currently being tested in late-stage studies to determine their effectiveness in preventing COVID-19.

Sinovac’s findings, published in a peer-reviewed article in the medical journal The Lancet Infectious Diseases, came from the results of Phase I and II clinical trials in China that included more than 700 participants.

“Our results show that CoronaVac is able to induce a rapid antibody response within four weeks of immunization by giving two doses of the vaccine 14 days apart,” said Zhu Fengcai, one of the authors of the paper.

“We believe this will make the vaccine suitable for an emergency during the pandemic,” said Zhu in a statement posted alongside the paper.

The researchers said the results of large late-stage or phase III studies would be crucial in determining whether the immune response generated by CoronaVac is sufficient to protect people from the coronavirus infection.

Sinovac is currently conducting three Phase III studies in Indonesia, Brazil and Turkey.

The results need to be interpreted with caution until the Phase III results are released, said Naor Bar-Zeev, a professor at Johns Hopkins University who was not involved in the study.

“But even then, we should remain cautious after the Phase III study is completed and licensed,” he said.



CoronaVac is one of three experimental COVID-19 vaccines that China has vaccinated hundreds of thousands of people as part of an emergency program.

The other two vaccines in China’s emergency program, both developed by institutes affiliated with Sinopharm, and another vaccine from CanSino Biologics <6185.HK>They have also been shown to be safe in early- and intermediate-stage studies and elicit immune responses, as shown by peer-reviewed articles.

Gang Zeng, a Sinovac researcher who was involved in the CoronaVac study, said the vaccine could be an attractive option because it can be stored at normal refrigerator temperatures of 2 to 8 degrees Celsius and can be stable for up to 3 years .

“(It) would provide some advantages for distribution to regions where access to cooling is difficult,” the author said.

Vaccines developed by Pfizer / BioNTech and Moderna use a new technology called synthetic messenger RNA (mRNA) to activate the immune system against the virus and require much colder storage.

Pfizer’s vaccine must be stored and transported at -70 ° C. However, it can be stored in a thermal shipping box in a regular refrigerator for up to five days or up to 15 days. Moderna’s candidate is expected to be stable for 30 days at normal refrigerator temperatures, but for storage up to six months it must be kept at -20 ° C.

CoronaVac will also be considered for vaccinations by Brazil and Indonesia in the coming months.

Indonesia has applied for an emergency permit to launch a mass vaccination campaign by the end of the year. The vaccines manufactured by Sinovac and Chinas Sinopharm are expected to be used in the early stages of the campaign.

The Brazilian company Sao Paulo is planning to introduce CoronaVac in January and has signed a supply contract with Sinovac.

“The excellent safety of CoronaVac compared to other vaccines under development leads to greater acceptance among the population,” Ricardo Palacios, study director of the biomedical center of the Butantane Institute in Brazil, which tests CoronaVac, told Reuters.

(Except for the headline, this story was not edited by GossipMantri staff and posted from a syndicated feed.)


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