However, the researchers mentioned in the study that they don't know for sure how much the vaccine would be protective against COVID-19 since they don't know much about the effectiveness of antibodies and T-cell response against the disease.
However, the scientists, including those from the Beijing Institute of Biotechnology in China said further research is needed to confirm whether the vaccine protects against SARS-COV-2 infection.
A coronavirus vaccine trialled in 108 healthy volunteers in China safely triggered an immune response in the participants, a new study reveals.
"However, these results should be interpreted cautiously".
"The challenges in the development of a COVD-19 vaccine are unprecedented, and the ability to trigger these immune responses does not necessarily indicate that the vaccine will protect humans from Covid-19", Chen explained.
Currently, more than 100 candidate COVID-19 vaccines are in development worldwide.
The vaccine, called Ad5-nCoV, is being developed by the Chinese company CanSino Biologics, and was one of the first coronavirus vaccines to enter early human trials back in March.
It uses a weakened common cold virus, adenovirus, which infects human cells but is incapable of causing disease, to deliver genetic material that codes for the SARS-CoV-2 spike protein to the cells. Participants received either a low, middle or high dose of the vaccine.
On day 14, all the participants showed the presence of antibodies which peaked at day 28 and T-cell response peaked at day 14 after the vaccination. The cells then produce the spike protein and stimulate the human immune system into generating antibodies that will recognise the protein and, researchers hope, will fight the coronavirus.
In addition, the researchers reported to have tested three doses and said that the highest dose seemed to be the most effective.
Most of the people dosed with the vaccine had immune responses, although their levels of antibodies thought to neutralize the virus were relatively low. Fever (46%), fatigue (44%), and headache (39%) were the most common systemic adverse events. However these effects lasted no more than 48 hours.
Levels of neutralizing antibodies - a type of immune cell that binds to a virus and may be able to completely block infection - were closely monitored too.
The phase 1 trial involved the substance being administered to 108 healthy volunteers in Hubei province, the original epicenter of the outbreak.
The vaccine also stimulated a rapid T cell response in the majority of volunteers, which was greater in those given the higher- and middle-doses of the vaccine, with levels peaking at 14 days after vaccination. "Moreover, high pre-existing Ad5 immunity may also have a negative impact on the persistence of the vaccine-elicited immune responses".
"Now, a pair of new studies led by researchers at (the Boston hospital) suggests the answer to these questions is yes, at least in animal models", researchers said.
Citing the main limitations of the trial, the authors said the study had a small sample size and was conducted in relatively short duration, with a lack of randomised control group.
The researchers have now started a larger, phase 2 study of the vaccine involving 500 participants who will be given a low or intermediate dose of the vaccine, or a placebo.
Limitations to the study, Chen and colleagues said, include that it was not created to measure vaccine efficacy, and that no participants were older than age 60, with only 16% of participants older than age 50.