CoronaVac doubles antibodies in those who already had Covid-19, research reveals

A study carried out by researchers at the Chongqing Medical University, in China, showed that CoronaVac, a vaccine by Chinese pharmaceutical Sinovac against Covid-19, manufactured in Brazil by the Butantan Institute, is able to double, in those who already had the disease, the amount of neutralizing antibodies and multiply by 4.4 times the level of immunoglobulin IgG.

Neutralizing antibodies are responsible for fighting any reinfection by SARS-CoV-2). IgG, on the other hand, is linked to the body’s defense process in which the immunoglobulins found in the blood stream act, and it also plays a key role in preventing viral reinfection.

Preliminary results of the research, carried out with 85 patients recovered from Covid-19, were published in Cell Discovery, a publication that is part of the British group Nature. Study participants were aged between 3 and 84 years and had mostly contracted the disease in early 2020.


According to the survey results, the level of neutralizing antibodies among people who took Covid-19, which was 36 a day before the first dose, rose until it reached 108 two weeks after the second dose. In the control group, this indicator reached 56 – that is, the amount of neutralizing antibodies generated by the vaccine in those who had already been contaminated with Covid-19 was double compared to those who had not had the disease.

Among convalescents, the level of immunoglobulin IgG, which was 3.68 the day before the vaccine, rose to 47.74 two weeks after the second dose of CoronaVac. It is an amount 4.4 times higher than the level of 10.81 detected in the control group.

However, over the 12-month follow-up of the 85 patients analyzed, the levels of neutralizing antibodies decreased from 631 at the end of the first month to 84 in the last month. In the case of immunoglobulin IgG, the indicator dropped from 28.6 to 7.2 in the same period.