The results of the first phase of clinical trials of a vaccine candidate in China show that it is safe, well tolerated and capable of generating an immune response against the SARS-CoV-2 coronavirus in humans.

The person responsible for this clinical trial – the vaccine has to pass three phases – is the Institute of Biotechnology in Beijing, China, and its results are published in the scientific journal The Lancet.

The study has been done in 108 healthy adults between 18 and 60 years old and shows “promising results” after 28 days, according to the authors, who nevertheless point out that more trials are needed to know if the immune response it provokes effectively protects against SARS-CoV-2 infection.

“These results represent an important milestone,” says Wei Chen of the Beijing Institute of Biotechnology, for whom this trial demonstrates that a single dose of the new vaccine, using an adenovirus vector type 5 (Ad5-nCoV), produces in 14 days specific antibodies against the virus and T cells – a type of white blood cell that plays a key role in the immune response.

This makes her “a potential candidate for further investigation,” says Chen, who nonetheless points out that the results should be interpreted with caution.

And, according to The Lancet, the ability to trigger immune responses does not necessarily indicate that the vaccine will protect humans from the disease.


“This result shows a promising vision for the development of the vaccine, but we are still a long way from making it available to everyone,” says Chen.

According to the magazine, the vaccine candidate evaluated in this trial is the first that has been tested in humans.

The vaccine, with the participation of the CanSino company, was well tolerated in all doses, with no serious adverse events reported in the 28 days after vaccination; in any case, most were mild or moderate.

The most common adverse reactions were mild pain, fever, fatigue, headache, and muscle pain.

Within two weeks of vaccination, all dose levels of the vaccine triggered some level of immune response in the form of binding antibodies (which can bind to the coronavirus but do not necessarily attack it); some of the participants had detectable neutralizing antibodies against SARS-CoV-2.

The vaccine also stimulated rapid T cell response in most volunteers, which was greater in those who received the high and medium doses of the vaccine.

The main limitations of the trial, the authors note, are small sample size, relatively short duration, and lack of a randomized control group, limiting the ability to detect rarer vaccine adverse reactions or to provide robust evidence. of its ability to generate an immune reaction.

Keep testing

Phase 2 of the trial has already started in Wuhan City to determine if the results can be replicated and if there are any adverse events for up to six months after vaccination.

Participating 500 healthy adults, 250 volunteers who were given a medium dose, 125 who were given a low dose and 125 who were given a placebo as a control.

For the first time, participants over the age of 60, a large population targeted by the vaccine, were included.

Earlier this week, US pharmacist Moderna reported the “positive” results of its vaccine also in a first phase of experimentation, which demonstrated “potential to prevent COVID-19 disease” in humans.