BEIJING (Reuters) – A coronavirus vaccine candidate developed by the Chinese Academy of Sciences (CAS) has been found to be safe and stimulate immune responses in early and midterm trials, researchers said Tuesday.
End-of-term testing of the ZF2001 vaccine, which CAS is developing with a unit of Chongqing Zhifei Biological Products, began last month in China. It aims to recruit 29,000 people across China, Uzbekistan, Indonesia, Pakistan and Ecuador.
The applicant did not cause serious adverse events, with common mild side effects including injection pain, redness and swelling, researchers at the Chongqing Zhifei unit, CAS, and other Chinese institutions said in a previous paper published Tuesday ahead of peer review. bit.ly/3nKZzt0
The combined data from Phase 1 and 2 trials included 950 healthy Chinese participants aged 18–59. Low-dose and high-dose versions were tested, and a Phase 2 study also tested two doses versus three doses for both the low-dose and high-dose versions.
The higher dose given by three injections 30 days apart did not induce a better immune response compared to the lowest dose, the paper said. A Phase 3 test will look at the lowest dose version given over three injections, he said.
Neutral antibodies against the virus were found among at least 93% of participants who received three blows in different groups. Levels of vaccine-induced antibodies were higher than those observed in samples of patients diagnosed with the disease, researchers said.
However, these antibody-based readings alone are not enough to predict how effective ZF2001 will be in protecting humans from the virus, researchers said, warning that they could not yet control it. determining the duration of immune responses.
The vaccine also triggers cell-based mediated immune responses, an essential part of the human immune system that works differently from antibodies.
ZF2001 is a protein subunit vaccine, which uses a harmless extract of the SARS-CoV-2 virus rather than the entire germ.
Four other Chinese vaccines from Sinopharm, Sinovac Biotech and CanSino Biologics have also entered Phase 3 clinical trials.
Reciting with Roxanne Liu and Ryan Woo; Edited by Edwina Gibbs