The donation of plasma by cured patients who had contracted the coronavirus must be made as quickly as possible after their recovery if it is to retain the greatest possible amount of antibodies, according to research conducted by seven Greek hospitals and research institutes which has been accepted for publication in the respected New England Journal of Medicine.
The research, which involved the Attikon, Evangelismos, Alexandra, Patra University and Sotiria hospitals, as well as the Pasteur Institute and the National Blood Donation Center, found that antibodies in cured Covid-19 patients dwindle over time. What remains unclear is whether the reduction in antibodies in turn reduces immunity to the virus.
The research was conducted on 259 potential plasma donors with confirmed infection and two negative tests following their treatment for Covid-19. The plasma was taken from each of the patients on average 12 days after the initial test to check for antibodies. It indicated a drop of 10-15% in the level of antibodies.
The asymptomatic patients (7.7% of the total) had a smaller concentration of antibodies than those who had symptoms, irrespective of whether they were hospitalized for treatment or not.
The findings signal that the donation of plasma from recovering patients must be carried out without delay to ensure a high volume of antibodies, the researchers said.