Study of Antibody Decay of SARS-COV-2

There have been recent questions regarding how long the immunity of a person who has been mildly affected by covid lasts. The rate of the depletion of the antibodies has not been determined very surely by a lot of researchers. The above researchers from the medical wing of UCLA, Los Angeles performed a group study where they chose people who had recovered from COVID-19 and had volunteered to be a part of the study. The study proceeded with the correct formalities and under the supervision of the board members. The study was started by drawing the blood and taking samples. These samples were assessed under the ELISA to detect the anti-coronavirus spike receptor-binding domain of IgG. Among the 34 participants, 30 had been confirmed for the coronavirus by the PCR test (polymerase chain reaction). The remaining 4 participants were also afflicted by the COVID-19 but were not tested due to limited resources and mild illness only. Out of the 34 participants, there were 14 men and 20 women chosen. The mean age range of the study ranged from 21 to 68 and the mean age was said to be 43. There were serial measurements taken for every individual for their IgG levels, for 31 participants two measurements were taken, and for the remaining 3, there were three obtained. These measurements were obtained after a particular period. The first one is said to be after 37 days of the onset of symptoms and the last one 86 days later. The initial mean IgG level was found to be 3.48log10ng per ml. There was a linear regression model that included the participants’ age and sex, even the days from onset of symptoms which showed a downward trend. The slope of the graph was derived to -0.0083log10 ng per ml. The change In the antibodies are variable from individual to individual and also varies drastically in time. The graph shows the variety of results that were obtained in every individual and how each of them had a variable slope of declination showing a different rate of depletion of the antibodies. There was a 95% confidence interval for the slope where the half-life was said to be expressed as 26 to 60 days.

Even after a lot of studies, the protective role of these antibodies against the Coronavirus is unknown but these antibodies usually give the needed antiviral immunity and help in making sure the virus can bind with the receptors. The decay of the antibody after exposure happens very rapidly and the slope is very sharp leading to the graph to be explained as an exponential one. Thus, the study performed by the group of researchers gives proof that humoral or immunity in the blood is not long-lasting for individuals who tend to have mild infections of the coronavirus, this is a little alarming as the majority of the individuals with Covid-19 show mild infections and not severe ones. The study could also not be continued after 90 days as the rate of the disappearance and decay slowly reduces and the amount of antibodies decelerates too. Thus, other measures such as vaccines, immunity passports, and herd immunity are needed to overcome this short-lived immunity
to a permanent long-term immunity.

Categories: News, Science