The patients who participated in this first test had a mean age of 36.3 years. The majority (51%) were men and all were healthy. They were divided into three equal groups: 36 received a low dose of the vaccine; another 36, a median dose; and the remaining 36, a higher dose.
Among volunteers who received the lowest dose, 30 (83%) reported at least one side effect in the first seven days after applying the vaccine. Another 30 (83%) of those who received the median dose and 27 (75%) of those who were vaccinated with the highest dose also reported at least one reaction.
The most common effect was pain, reported by 58 (54%) of the 108 patients. Fifty (46%) also had a fever; 47 (44%), fatigue; 42 (39%), headache; and 18 (17%), muscle pain. Most reactions, according to the study, were mild or moderate. No serious side effects were recorded within 28 days after vaccination.
The level of coronavirus neutralizing antibodies increased significantly on the 14th day, and peaked on the 28th day. The response of T lymphocytes, which also act to fight the disease, reached its maximum level on the 14th day after vaccination.
This differentiation is important because, according to the scientists, it is not enough that the vaccine is able to make the body produce antibodies against the coronavirus. It also has to induce the response of T cells, which are responsible for defending against unknown agents.
The findings are preliminary, but promising, and “suggest that the covid-19 vaccine with Ad5 vector deserves further investigation,” conclude the Chinese scientists.