SERPENCELESSNESS OF ANTIBODIES TO SARS-CoV-2 IN CHILDREN AGAINST THE BACKGROUND OF THE COVID-19 EPIDEMIC IN THE RUSSIAN FEDERATION
Authors:   Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Moscow, Russia, Popova A.Yu. , Smirnov V.S. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia, Andreeva E.E. ,   Moscow City Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Moscow, Russia, Arbuzova T.V. ,   Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Moscow, Russia, Babura E.A. ,   Kaliningrad Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Kaliningrad, Russia, Balakhonov S.V. ,   Irkutsk Antiplague Research Institute of Siberia and Far East awarded by the Labour Red Banner, Irkutsk, Russia, Bashketova N.S. ,   Saint Petersburg City Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Saint Petersburg, Russia, Bugorkova S.A. ,   Russian Research Anti-Plague Institute "Microbe" with the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Saratov, Russia, Bulanov M.V. ,   Vladimir Oblast Regional Center for Hygiene and Epidemiology with the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Vladimir, Russia, Valeullina N.N. ,   Chelyabinsk Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Chelyabinsk, Russia, Goryaev D.V. ,   Krasnoyarsk Krai Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Krasnoyarsk, Krasnoyarsk Krai, Russia, Gubanova A.V. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia, Detkovskaya N.N. ,   Primorsky Krai Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Vladivostok, Primorsky Krai, Russia, Ezhlova E.B. ,   Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Moscow, Russia, Zhimbayeva O.B. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia, Zaitseva N.N. ,   Academician I.N. Blokhina Nizhny Novgorod Scientific Research Institute of Epidemiology and Microbiology with the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Nizhny Novgorod, Russia, Zueva E.V. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia, Ivanov V.A. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia, Istorik O.A. ,   Leningrad Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Saint Petersburg, Russia, Kovalchuk I.V. ,   Stavropol Krai Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Stavropol, Stavropol Krai, Russia, Kozlovskikh D.N. ,   Sverdlovsk Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Yekaterinburg, Sverdlovsk Oblast, Russia, Kombarova S.Y. ,   G.N. Gabrichevsky Moscow Scientific and Research Institute of Epidemiology and Microbiology (Gabrichevsky MRIEM), Moscow, Russia, Kurganova O.P. ,   Amur Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Blagoveshchensk, Amur Oblast, Russia, Lomovtsev A.E. ,   Tula Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Tula, Russia, Lukicheva L.A. ,   Murmansk Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Murmansk, Russia, Melnikova A.A. ,   Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Moscow, Russia, Mikailova O.M. ,   Moscow Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Mytishchi, Moscow Oblast, Russia, Milichkina A.M. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia, Noskov A.K. ,   Rostov-on-Don Plague Control Research Institute with the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Rostov-on-Don, Russia, Noskova L.N. ,   Astrakhan Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Astrakhan, Russia, Oglezneva E.E. ,   Belgorod Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Belgorod, Russia, Osmolovskaya T.P. ,   Krasnodar Krai Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Krasnodar, Krasnodar Krai, Russia, Patyashina M.A. ,   Tatarstan Republican Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Kazan, Republic of Tatarstan, Russia, Penkovskaya N.A. ,   Crimean Republican Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Simferopol, Crimea, Ukraine, Petrova O.A. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia, Razumovskaya A.P. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia, Samoilova L.V. ,   Novosibirsk Oblast Regional Department of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Novosibirsk, Russia, Stepanova T.F. ,   Tyumen Research Institute of Western Siberia Krai Regional Infectious Pathology with the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Tyumen, Russia, Trotsenko O.E. ,   Khabarovsk Research Institute of Epidemiology and Microbiology with the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Khabarovsk, Khabarovsk Krai, Russia, Khamitova I.V. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia, Totolian A.A. ,   Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg, Russia
Published: May 2022

Objective: to study the seroprevalence of SARS-CoV-2 antibodies (AB) in children in the 2nd year of the COVID-19 pandemic in Russia. Materials and methods: prospective cohort study. The seroprevalence research was conducted among 3670 children aged 1 to 17 y/o from 26 modelling regions of Russia (that have been participating earlier in the five stages of seromonitoring during 2020-2021). The serological testing was carried out in December, 2021. The work was carried out according to a unified methodology set by the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being with the Pasteur Institute of Epidemiology and Microbiology (Saint Petersburg, Russia). The plasma was obtained from 3 ml of venous blood, in which the level of AB to nucleocapsid (NC), and the SARS-CoV-2 receptor-binding domain (RBD) was determined by immunoferment method using reagents for qualitative and quantitative analysis. Results: the analysis of AB seroprevalence to NC and RBD showed the statistically significant increase in the share of seropositivity to RBD in children of all modelling regions (p<0.05). The most seropositive volunteers contained low levels of AB: 31.3-125.6 BAU/ml NC and 22.6-220 BAU/ml RBD. An increase in the level of AB to NC and RBD was accompanied by a decrease in the percentage of seropositive patients. Evaluating the contribution of children to the level of humoral immunity, convalescents (had been ill shortly before the examination), the “anamnesis” (had been ill at previous stages of seromonitoring) and asymptomatic (had been asymptomatically ill) groups were distinguished. The maximum contribution was made by children with asymptomatic cases of COVID-19 in anamnesis: in 82.3% (95% CI 81.1-83.6), of which 76.9% (95% CI 75.5-78.3) AB detected to RBD. The contribution of children of two other groups to the overall level of humoral immunity was 33 times less. Conclusion: statistically significant predominance of AB to RBD above AB to NC and their main contribution to the level of humoral immunity to SARS-CоV-2 (p<0.001).