The Ministry of Health of the Russian Federation recommends evaluating post-vaccination immunity by the presence of anti-RBD antibodies

The Ministry of Health of the Russian Federation recommends evaluating post-vaccination immunity by the presence of anti-RBD antibodies

On October 26, 2020, the Ministry of Health of the Russian Federation published the ninth version of the temporary guidelines Prevention, diagnosis, and treatment of the new coronavirus infection (COVID-19) on its official website.

In particular, the new version of the document contains a separate section on specific prevention of COVID-19 in adults. It states that the Russian Federation has registered two vaccines for the prevention of new coronavirus infection COVID-19 in adults aged 18 to 60 years, inducing the formation of humoral and cellular immunity against SARS-CoV-2 (Gam-COVID-VAC and EpiVacCorona). The use of these vaccines is recommended as a priority for the prevention of morbidity among employees of medical institutions, educational organizations, shops, the police, and a number of other groups of citizens who, due to their professional activities, are subjected to special risk.

At the same time, according to the new guidelines of the Russian Ministry of health, numerous studies have shown that more than 80% of virus neutralizing antibodies are directed towards the receptor-binding domain (RBD) of the SARS-CoV-2 S-protein. Therefore, it is the determination of antibodies to the receptor-binding domain (anti-RBD antibodies) that the Ministry of Health recommends in order to assess the intensity of post-vaccination protective immunity by the method of enzyme immunoassay.

The receptor-binding domain (RBD) is a special protein structure located on the «crown spikes» of the new coronavirus. Using RBD, the virus binds to the receptor of a human cell and enters it. In this case, the human immune system detects the receptor-binding domains of the virus and produces anti-RBD antibodies in response, blocking them and thereby preventing the virus from entering the cells. The SARS-CoV-2-RBD-ELISA-Gamalei reagent kit for the immunoassay detection of immunoglobulins G to the receptor-binding domain of the SARS-CoV-2 coronavirus surface glycoprotein S (spike) was developed by the N. F. Gamaleya National Research Center, and has already been launched into mass production using manufacturing capabilities of the Nearmedic Plus company.

In October, the first batch of such testing kits was delivered to the Nearmedic clinics in Moscow and the Moscow region.

«One needs to understand that it is not just any IgG antibodies that protect against catching the new coronavirus infection, but the anti-RBD antibodies, which, unfortunately, may not be produced in sufficient quantities even after a previous illness, especially if it was mild, or may disappear within 6 months after the disease. Therefore, only the new generation test systems for determining anti-RBD antibodies among all IgG immunoglobulins, which include the SARS-CoV-2-RBD-ELISA-Gamalei tests, can reliably determine the patient’s actual present COVID-resistance. This method is also relevant for assessing post-vaccination immunity,» explains Maria Kolomentseva, General Director of the Nearmedic chain of clinics.

The study for the determination of anti-RBD antibodies is carried out in a laboratory environment, with the use of venous blood serum as biomaterial; the analysis results may be obtained in a matter of one day to three days.