According to details, the vaccine that is undergoing the third phase of a clinical trial in Pakistan has shown positive results with 95 percent recovery rate of the patients who were about to be shifted on a ventilator. Phase III results must be published to provide a more conclusive picture, said Naor Bar-Zeev, a professor from Johns Hopkins University who was not involved in the study, said.
This, the biotech said, is based on its experience with other vaccines and data from preclinical studies with macaques.
Commenting on the findings, Zhu Fengcai, one of the authors of the paper, said: "Our findings show that CoronaVac is capable of inducing a quick antibody response within four weeks of immunisation by giving two doses of the vaccine at a 14-day interval".
Two other drugmakers, Pfizer and Moderna, this week reported preliminary results from late-stage trials showing that their COVID-19 vaccines were nearly 95% effective.
The US regulators will meet on December 10th to discuss whether to authorise the Covid-19 vaccine developed by Pfizer and German partner BioNTech for emergency use, the US Food and Drug Administration has said.
Indonesia, Turkey and Brazil are now in phase 3 trials of CoronaVacwith tens of thousands of participants.
Dr. Andrew Pollard leads the University of Oxford study.
Vials of the Oxford coronavirus vaccine
China has been testing vaccines since April. Like with other kinds of vaccines, mass producing them for the coronavirus has proved to be a complex and delicate process requiring sterile conditions and precise control of temperature and humidity.
Researchers say their findings are promising as they show that the older people are showing a similar immune response to younger adults. "(It) would offer some advantages for distribution to regions where access to refrigeration is challenging", he said.
CoronaVac uses inactivated coronavirus, making it different from the mRNA, or messenger RNA, vaccines produced by Pfizer and Moderna.
Pfizer's vaccine must be stored and transported at minus 70 deg C, though it can be kept in a normal fridge for up to five days, or up to 15 days in a thermal shipping box.
Thirteen serious adverse events occurred in the six months since the first dose was given, none of which were related to either study vaccine.
Earlier in the week United States biotech firm Moderna released data suggesting its vaccine is nearly almost 95% effective.