Universitas Pelita Harapan (UPH) Lecturer in Biotechnology, and also a researcher at the Mochtar Riady Institute of Nanotechnology (MRIN), Dr. rer. nat. dr. Juandy Jo, conducted a research on the antibody titers entitled ‘Assessment on Anti-SARS-CoV-2 Receptor-Binding Domain Antibodies among CoronaVac- Vaccinated Indonesian Adults’ published in the journal Clinical and Experimental Vaccine Research (2022;11(1):116-120). This study started in April 2021, with the purpose of observing the function of human antibodies after vaccination to combat the Covid-19 virus.
“Back then during the early days of Covid, we tested human antibodies or our body’s resistance toward Covid virus, which showed reactive or non-reactive results. In addition, when Indonesia started vaccination, people began to test antibody titers or antibody numbers so that they could understand whether there were enough antibodies to deal with the new coronavirus. Unfortunately, many do not know whether their antibodies really work in fighting with the Covid virus. This has then become the main purpose of this research,” said Dr. dr. Juandy Jo.
In this study, Dr. dr. Juandy Jo paid special attention to human antibodies vaccinated with Sinovac. Then he divided them into three categories for comparison. The first group were those who had been vaccinated with the Sinovac vaccine. The second group was for Covid survivors and the last group were people who were not vaccinated and who have never been confirmed to be infected with Covid. Interestingly, the results of this study showed a significant difference between the first group and the second group.
The result is that the two doses of Sinovac vaccine induced a complete conversion in naïve adults of SARS-CoV-2 with anti-SARS-CoV-2 Receptor-Binding Domain (RBD) antibody titers from 9,1 to 151,9 U/mL. A median of less than one was observed in adults who recovered from COVID-19 with mild symptoms (38,7 vs 114,5 U / mL). Nevertheless, 93,6% of vaccinated adults, unlike 76,5% of recovered adults, showed a level of inhibition above the limit to prevent RBD-ACE2 binding. This indicates that the two doses of CoronaVac are immunogenic and tend to have a protective effect on Indonesian adults.
“If we just measure the quantity or the amount of antibody, the result will be that the antibody of the Covid survivor with mild symptoms will be 4 times higher than that of those who have been vaccinated twice with Sinovac. If we look at the results of this study, people would think that Sinovac vaccine seems unnecessary. Finally, I did some research, which looked for the function of antibodies in the human body. It turned out that the function of the antibodies produced by the Sinovac vaccine is quite good; the level is almost the same with the antibody function of the survivors. This shows that the antibodies produced by the Sinovac vaccine, although they are only in small amounts, but they can work,” explained Dr. dr. Juandy Jo.
According to him, the Sinovac vaccine will really work, especially when the Delta variant is on the rise. This vaccine works by reducing the level of severity of those infected and reducing the death rate of those infected. These two things are very useful compared to people who have never been vaccinated.
“Don’t just measure the amount of antibodies. The large number of antibodies based on the test results does not guarantee that a person will be immune to Covid, and the amount of antibodies may vary from time to time. And then, the Sinovac vaccine can work effectively to reduce severity and even death,” he said.
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