The high protection provided by the vaccine against all coronavirus mutations is underlined by a study of the EKPA for the immune response after the full vaccination against SARS-COV-2.
The Therapeutic Clinic of his Medical School ΕΚΠΑ, from the beginning of the vaccinations of the Greek population, launched a comprehensive prospective study to record the immune response to vaccination against SARS-CoV-2.
Specifically, the purpose of the prospective study NCT04743388 carried out at "Alexandra" Hospital is to assess the kinetics of antibodies against RBD of Spike protein (S-RBD)and neutralizing antibodies (NAbs)against the SARS-CoV-2 virus in healthcare professionals, adults from 70 to 90 years and patients with neoplastic disease after vaccination with mRNA vaccine BNT162b2 (ComirnatyTM) of Pfizer / BioNTech. Antibodies detected by commercially available techniques are reported in the original SARS-CoV-2 strain, the Wuhan executive. However, these antibodies can neutralize other mutations such as the delta that currently dominates in our country.;
The study of EKPA shows that:
- Vaccination also provides high protection against the SARS-CoV-2 Delta strain, since it causes the production of very high neutralizing antibody titers against the original WA1 strain.
- SARS-CoV-2 booster vaccination increases the level of antibodies against WA1 and, hence, the increased ability to recognize the delta variant.
Vaccination with a single dose of COVID-19 vaccine, 6-10 months after their illness, provides them with complete protection against the delta variant.
In the EKPA study, the researchers measured the size and range of antibodies against the coronavirus Spike protein and their neutralizing ability against the original strain of the virus. (Wuhan-WA1 strain) and 3 variants of the virus (alpha-B.1.1.7, beta-B.1.351 and delta-B.1.617.2), which differ by one to three amino acids within the RBD receptor.
The measurements were made in 3 groups of volunteers:
(a)55 healthy recipients of two doses of BNT162b2 mRNA vaccine (Pfizer/BioNTech), 3 months after their full vaccination;
(b) 5 Patients who recovered from COVID-19 and received the first single dose of BNT162b2 mRNA 6-10 months after the onset of symptoms (the measurements were made here as well 3 months after the vaccine dose)·
(c) 23 patients recovering from COVID-19, in the intermediate period 2 months after the onset of symptoms.
The study was conducted in collaboration with the retrovirus team at the US National Cancer Institute (Professors George Pavlakis and Barbara Felber) and its main effects, published in the prestigious American Journal of Hematology, analyzed by the study coordinators, EKPA professors Evangelos Terpos (Professor of Hematology) and Thanos Dimopoulos (rector of EKPA). In addition, Margherita Rosati participated in the writing of the publication , Mahesh Agarwal, Evangelos Karalis, Jenifer Bear, Robert Burns, Xintao Hu, Dimitrios Papadimitriou, Ioannis Danasis-Stathopoulos and Ioannis Trougakos.
It was observed in all three groups studied strong antibody response against the Spike-RBD protein of strain WA1. Similar antibody levels were detected in healthy fully vaccinated and in patients after recovery by COVID-19, while 12 A higher level of antibodies was found in people with COVID-19 who received a single dose of the vaccine., as a result of a strong memory response in this group.
Compared to WA1 responses, Vaccine-induced antibodies showed lower recognition of Spike-RBD in alpha and delta variants and significantly reduced Spike-RBD binding to beta variant.
On the contrary, antibodies to Spike-RBD in vaccine recipients after recovery from COVID-19 but also in those recovering from COVID-19 infection showed similarly strong binding to Spike-RBD protein of all alpha variants, beta and delta.
The blood of the participants was also studied for its neutralizing action (neutralizing antibodies) against the original executive WA1 and 3 variants. A strong direct correlation was found between the neutralizing antibodies against the WA1 strain and the delta variant, showing that individuals with high titers of neutralizing antibodies (achieved by vaccination) against WA1 effectively neutralize the delta variant.
However, some differences were found between the three groups studied. The neutralizing antibodies produced by the vaccine have 20% approximately less effective against the delta variant than the original WA1 virus strain.
On the contrary, antibodies caused by SARS-CoV-2 infection have better neutralization function for the delta variant, while vaccination of those recovering from COVID-19 was able to increase the level and maintain the range of antibody neutralization against the delta variant, providing complete neutralization of the mutated virus.