A study by the King George’s Medical University (KGMU), has found that antibodies formed after vaccinations were stronger and lasted longer whereas those generated after infection fizzled out in less than four months. The study further found that the desirable herd immunity which can break the chain of virus can only be achieved by mass vaccination and not through the natural course of transmission of infection.
In the two-part study, there were 989 healthcare workers which included class four employees, junior doctors, staff, and senior faculty members, 869 (88 percent) had antibodies. Of 869, about 73 percent had completed a two-dose vaccination course, and 13 percent had taken only one dose. The remaining were those who had not taken vaccines but had acquired infection.
The test results showed that about 61 healthcare workers had not developed adequate antibodies even after taking both doses. Likewise, there were 25 workers who had taken a dose but had not developed antibodies. And the remaining who lacked antibodies had not been vaccinated so far.
Besides, of the 500-odd plasma donors who came for donation 14 days to three months after recovery, only 50 percent were found to be having adequate antibodies. These donors had either lost their antibodies prematurely or just did not produce enough. The reason could be because of low immunity or less severe infection.
“This shows the probability of developing adequate antibodies that also last for a long period through vaccination, rather than acquiring infection in a natural way. The high percentage of antibodies in this group is a good sign, hinting at herd immunity through vaccination. Generally, when a person is infected, memory cells in the body store the information of infection. Hence, even if antibodies are not formed, it is assumed that memory cells will be able to fight the infection if a person is exposed to the risk again. But the second wave saw many cases of re-infection due to which scientists presumed that memory cells did not work well in them,” notes Prof Tulika Chandra, head of the transfusion medicine department.
The University further targets a sample size of 4,000 which can bring about more revelations. Some of the vaccinated healthcare workers tested in the first round will be tested again later to determine the longevity of the antibodies developed from vaccination.