Data from the Greece for the duration of the presence antibodies against the SARS-CoV-2, after 8 months of natural infection, have recently been accepted for publication in the official journal of the European Society of Internal Medicine, European Journal of Internal Medicine. In this pioneering study, 148 people who recovered from infection were examined COVID-19, All participants had a confirmed diagnosis of SARS-CoV-2 infection by PCR followed by two negative PCR results for SARS-CoV-2, with an interval of 7 days. The coordinators of the study, are the Professors of Hematology at the School of Medicine of the EKPA, Evangelos Terpos, Marianna Politou and Meletios A. Dimopoulos (Rector of the University of Athens) and Professors Georgios Pavlakis, Director of the Department of Human Retroviruses at the National Cancer Institute (NCI), USA and Barbara Felber, Director of the Department of Human Retrovirus Biology at the National Cancer Institute (NCI), USA.
At the time of diagnosis of COVID-19, 91 (61.5%) patients were symptomatic but did not require hospitalization and 57 (38.5%) were hospitalized in Greek hospitals. Three blood samples were obtained for measurement of antibodies against SARS-CoV-2. The first sample at 2 months after the day of the first symptoms of the disease, the second after 6 months and the third after 8 months from the first symptoms of the disease. Antibodies were measured against the viral spike protein (Spike, S), against the receptor by which the virus enters human cells and located at the tip of the spike protein (Spike Receptor Binding Domain, S-RBD), against the nucleocapsid protein (Nucleocapsid, N) and against the part of the latter that binds to the viral RNA (Nucleocapsid RNA Binding Domain, N-RBD). At the same time, neutralising antibodies against the virus were measured at the above intervals using pseudovirus.
Antibodies against SARS-CoV-2 were detected in all subjects participating in the study, at the start of the study. Six and 8 months after the first symptoms of infection, the antibodies showed a two-phase reduction curve (significant reduction between 2 and 6 months and much smaller between 6 and 8 months). However, 8 months post-infection, all participants continued to have antibodies against S and S-RBD proteins, and 95% participants also had antibodies against N and N-RBD. Neutralizing antibodies showed a greater decrease and remained positive in the 75% of study participants. Of particular interest patients who were hospitalised had very high coronavirus neutralising antibody titres compared to those who did not require hospitalisation, at all time intervals of the study. The presence of neutralizing antibodies was strongly associated with the presence of antibodies against the viral antigen S-RBD.
This study is particularly important as it shows that natural antibodies are retained for 8 months after infection in the vast majority of patients after COVID-19, say the teachers. They believe that because vaccines produce very high antibody titres, higher than those of natural disease, the antibody immunity they provide will last for at least an equal period of time.
This study was made possible with the participation of many Greek scientists from various Greek centres and the NCI of the USA. In particular, the collection of samples for the study of antibodies and their laboratory detection was carried out in the following centres (with the respective researchers):
General Hospital of Athens «Alexandra» (E. Terpos, E. Koroboki, I. Haritaki, Th. Sergentanis, I. Danasis-Stathopoulos, T. Bagratouni and M.A. Dimopoulos)
University Hospital «Aretaio» (M. Politou)
Attikon University General Hospital (V. Pappa, A. Antoniadou, A. Bouchla, S. Papageorgiou and S. Tsiodras)
General Hospital of Athens «Evangelismos» (M. Pagoni, Ch. Yatra and A. Kotanidou)
Athens Cancer Oncology Hospital «St. Savas» (E. Grouzi and D. Moshandreou)
Department of Retroviruses NCI USA (B.K. Felber, D. Stellas, M. Rosati, D. Donohue, S. Karaliota, J. Bear, X. Hu and C. Pavlakis)
