Tuesday, July 06, 2021
By Mr. Stavros Fountoulakis, Biopathologist, Head of the Biological Materials Laboratory, Euromedica Heraklion
Coronavirus (SARS-CoV-2) encodes 4 major structural proteins: protein S (Spike), protein E (Envelope), protein M (Membrane) and protein N (Nucleocapsid). Of these 4, the S protein is responsible for the entry of the virus and the infection of human cells. Therefore, monitoring of antibodies to the S protein, provides valuable information to the clinician as it will be possible to evaluate the effectiveness of the vaccine, depending on the age and the wider profile of the vaccinated. Similarly, valuable conclusions are given for those who have been infected with the coronavirus in the past.
The impending immune response leads to the production of antibodies (anti-sars-cov-2-Spike) that offer protection by neutralizing viral spikes after disease or vaccination, i.e. preventing the virus from entering the body’s cells.
Antibody test – useful conclusions
In the past three months, March to June, 500 people were tested for antibodies in all Euromedica medical unites, i.e. the diagnostic centers of Heraklion & Rethimno and the maternity clinic “Mitera Kritis” in Heraklion.
Of the 500 tests, 290 were positive and 210 were negative. In other words, 58% of the sample had either become ill or had been vaccinated. Out of the 290, only 24 people presented a positive but single-digit title, which may be related to reduced protection. 14 of them had been ill in the past, 8 had been partially vaccinated (1 dose) and 2 had been fully vaccinated (2 doses). The fully vaccinated were over 75 years of age and following a re-test two months later, their antibody title had a slight increase.
In addition, in the Euromedica “Mitera Kritis,, placental transfer of antibodies from mother to newborn was found in two cases. More specifically, in deliveries on 21/4 and 10/5, newborns were tested after their first 24 hours in life and presented with a negative molecular test but with a positive antibody title, while their mothers were positive for antibodies. These are essentially children born with coronavirus immunity from mothers who had developed antibodies.
Our observations lead us to the conclusion that on the one hand those who have been vaccinated with the disease should monitor the course of their antibodies, on the other hand with the continuation of the vaccination program, the coveted herd immunity is now close.
Antibody Test
Antibody test are performed in all diagnostic centers of the Euromedica group, by simple blood sampling and approved methods with certified reagents (CE – IVD) for the analysis. The test is recommended to be performed in the following cases:
– 14 days after the onset of symptoms or confirmation of infection (positive PCR test)
– 20 days after the 2nd vaccination
