Immunity to SARS-COV-2 is maintained for at least six months after complete vaccination with the Pfizer / BioNTech vaccine, according to the latest results of the prospective study of EKPA conducted at the "Alexandra" hospital since the beginning of the vaccination of the Greek population.
The results so far have been published in the form of 20 articles in reputable international journals. In the most recent publication, the researchers presented the results from 308 health workers and employees of the Hospital, with a median age of 48 years, as he states in an interview with FM Agency and in the show of Tania H. Mantouvalos "104, 9 SECRETS OF HEALTH" - Oncology-Hematology, rector of EKPA, who is also the scientific responsible for the study Mr. Thanos Dimopoulos.
The rector, referring to the variation of neutralizing antibodies at 3 and 6 months, but also to the role that age plays, explains that more than 95% of those vaccinated had very high titers of virus neutralization about 4 months after the start of their vaccination. "Regarding the results of the 6 months after the full vaccination, the median value of neutralizing antibodies was 81%. At 3 months there was no one with neutralizing antibody values below the 30% positivity threshold, while 6 months after full vaccination only 2,59% (8 subjects) had antibody values below 30% and 12% had values below 50%. The decrease in antibody titer was greater in individuals aged 51-70 years, compared with those aged 20-50 years, at all times of the measurements.
Mr. Dimopoulos emphasizes that our healthy fellow citizens, especially up to the age of 70, do not need to have antibody tests, while when asked about how the scientific community will manage patients with hematological malignancies that are known to not have a good "answer "We have studied patients with various hematological malignancies and our results show that about 40% of these patients do not develop neutralizing antibodies. We do not know if a possible third dose of the same or another vaccine would be effective. We will see this in the new study of EKPA with this subject. On the other hand, the prophylactic administration of monoclonal antibodies, monthly (when they are approved for prophylaxis in these patients), during the period of an outbreak of the pandemic, could possibly protect individuals who may not have an immune response. There are such studies that are ongoing in the US. "The study of the Therapeutic Clinic of EKPA, according to the professor, will continue with the study of all vaccines and their effectiveness, up to 18 months after their first dose.
The text of the interview follows in detail:
Q: What was the purpose of your study, in which hospitals has it been conducted since when, and in what sample?
A: At the Therapeutic Clinic of the Medical School of EKPA, which is based at the "Alexandra" Hospital since the beginning of the vaccinations of the Greek population, we started an extensive prospective study to record the immune response to vaccination against SARS-CoV-2, with the main researcher Hematology of EKPA Mr. Evangelos Terpos. The purpose of this study, which has been approved by the competent authorities in the Scientific Council of the Hospital, is to assess the kinetics of antibodies against elements of the spike protein, and also to determine the neutralizing antibodies against the SARS-CoV-2 virus in health who were volunteers from the Hospital, to people over 80 years old, as well as to patients with various neoplastic diseases that we monitor and treat, within the Oncology Hematology Unit of the Therapeutic Clinic. These are people who have received a vaccine from either Pfizer or Moderna. The results so far have been published in the form of 20 articles in reputable international journals. In the most recent publication we have results in the health workers and employees of GNA "Alexandra" six months after their full vaccination with the Pfizer / BioNTech vaccine. The study involved 308 health workers and hospital staff (median age 48 years). The study of the Therapeutic Clinic of EKPA will continue with the study of all vaccines and their effectiveness up to 18 months after their first dose.
Q: Where and how were the antibodies determined?
A: The antibodies against the RBD portion of the virus spike protein were measured in the Biochemistry Department of the "Agia Sofia" Children's Hospital by the team of Mr. Ioannis Papasotiriou. The neutralizing antibodies were measured in the Biology Department of EKPA by the team of Professor Ioannis Trougakos. Antibodies were determined on days 1 (D1, before the first dose of the vaccine), D8, D22 (before the second dose of the vaccine), D36 (two weeks after the second dose), D50 (four weeks after the second dose), 3 and 6 months after the second dose.
Q: How does the value of neutralizing antibodies fluctuate between 3 and 6 months and what role does age play?
A: Neutralizing antibody values increased significantly on day 22 and reached their maximum value after the second dose (D36), showing a growth rate of 3% per day and reaching an average value of 97,2% of virus neutralization on day 36 , ie two weeks after the second dose of the vaccine. Values remained high on day 50 (median neutrality ≥95%) as well as 3 months after the second dose of vaccine (median neutralization 92,7%). Despite the small drop after the second week of full vaccination, which amounted to 0,11% per day, more than 95% of those vaccinated had the highest titers of virus eradication approximately 4 months after the start of their vaccination. Regarding the results of 6 months after full vaccination, the median value of neutralizing antibodies was 81%. At 3 months there was no one with neutralizing antibody values below the 30% positivity threshold, while 6 months after full vaccination only 2,59% (8 subjects) had antibody values below 30% and 12% had values below 50%. The decrease in antibody titer was greater in size in subjects aged 51-70 years compared with those aged 20-50 years, at all times of the measurements. Our study shows that in a healthy population under the age of 70 that was our sample, there is a slight decrease, but if one uses the values that have been standardized for neutralizing antibodies, at least six months, the coverage is satisfactory in the vast majority of people vaccinated.
Q: How long will we feel safe after the vaccine? We constantly hear different things about immunity
A. You are absolutely right. What we know from our own studies and from internationals with a large number of individuals, is that there is a gradual decrease in neutralizing antibodies, but it seems that at least in the healthy population, these levels are satisfactory for six to eight months. The results of our study show the high efficacy of the vaccine, as approximately 7 months after the first dose of the vaccine, almost all healthy study participants had very high COVID-19 protection titers. On the question of the duration of neutralizing antibodies after vaccination, judging by the results in Greek patients with COVID-19, and 75% retained the neutralizing antibodies at least 8 months after the first symptom, we believe that antibodies from vaccination will last for at least a year in the vast majority of healthy people. This is due to the fact that the vaccinated develop neutralizing antibody titers much higher even than those who contracted COVID-19 and needed hospitalization, while their rate of decline is low.
Q: Finally, how useful is it to do antibody tests
A: There is no indication that we should test for antibodies in the general population. The data I mentioned to you suggest that our healthy fellow citizens, especially up to the age of 70, do not need to have antibody tests, as the chance of not having developed high titers, even 6 months after full vaccination, is almost zero.
Q: We know that patients with haematological malignancies do not respond well to the vaccine. How will the scientific community deal with these cases?
A: We studied patients with various hematological malignancies, eg 276 patients with multiple myeloma, 170 with lymphomas of various types, 106 with chronic lymphocytic leukemia and 86 patients with systemic amyloidosis. The results show that about 40% of patients with the above diseases do not develop neutralizing antibodies. These diseases, by their nature, are accompanied by severe immunosuppression, while the treatments administered significantly affect the chemical immune response, ie the production of antibodies. In particular, those treated with monoclonal antibodies develop neutralizing antibodies in small amounts after vaccination (between 20% -40%). The question is what is the best treatment for these patients, who do not develop antibodies to SARS-CoV-2. We do not know if a possible third dose of the same or another vaccine would be effective. We will see this in the new study of EKPA with this subject. On the other hand, prophylactic administration of monoclonal antibodies, monthly when they are approved for prophylaxis in these patients, during a pandemic outbreak, could possibly protect those individuals who may not have an immune response. There are such studies that are ongoing in the US.
Q: Because the flu vaccine is about to start, do you know how the two vaccines will be given? Together or with a difference of days? What is provided?
A: There is no contraindication to doing them at the same time, but because sometimes we may have some mild side effects from the vaccines, one could do them a short distance, a week or a month.