Characteristic of herd immunity among the population of Stavropol region amid the COVID-19 epidemic

Introduction. The first pandemic in the 21st century, caused by the pathogenic representative of the coronavirus SARS-CoV-2, began in the Chinese city of Wuhan, where the first outbreak of coronavirus pneumonia was recorded in December 2019. The disease spread so quickly around the world that already on February 11, 2020, WHO was forced to declare a pandemic of the “coronavirus disease 2019” COVID-19. The first case of COVID-19 in the Stavropol Territory was registered on March 20, 2020, and three weeks later, starting from the 15th week of the year, a steady increase in the incidence began, which lasted until the 52nd week. During the study period, the incidence increased from 21.1 to 28.3 per hundred thousand of the population. Growth 1.3 times.

Purpose: to determine the dynamics of population immunity among the population of the Stavropol Territory in 2020-2021. during the period of an epidemic increase in the incidence of COVID-19. Materials and methods. The SARS-CoV-2 study was carried out according to a unified methodology within the framework of the program for assessing the population immunity of the population of the Russian Federation, developed by Rospotrebnadzor with the participation of the St. Pasteur. In total, 2688 people were examined, divided into 7 age groups. In the examined individuals, the level of specific IgG to the SARS-CoV-2 nucleocapsid was determined by the enzyme immunoassay.

Results. The level of seroprevalence among residents of the Stavropol Territory was 9.8%. The largest proportion of seropositive individuals was found in the age groups 1-6 and 7-13 years old (19.2% and 19.7%, respectively). Seroprevalence had no gender differences and ranged from 9.3% to 10.8%. When assessing the distribution of the proportion of seropositive persons in different geographic territories of the region, it was found that the maximum proportion was found in the Kochubeevsky district (23.1%), the minimum in Kislovodsk (7.7%). Among convalescents, the content of specific antibodies to SARS-CoV-2 was noted in 73.3%, which is 7.8 times higher than the average population level. When conducting seromonitoring in the 2nd half of 2020, a 10-fold increase in seroprevalence was recorded, accompanied by a decrease in incidence from the 5th week of 2021. Among asymptomatic volunteers in whom SARS-CoV-2 RNA was detected by the polymerase chain reaction, antibody titers to viruses were found in 78.6%, which corresponds to the seroprevalence of convalescents. The proportion of seropositive persons among those who have come into contact with COVID-19 patients was 16.4%, (1.8 times higher than the average for the population). Out of 262 seroprevalent volunteers, the asymptomatic form of SARS-CoV-2 was detected in 92% of the examined, which indicates a significant role of the number of asymptomatic forms of infection in the epidemic process of COVID-19.

Conclusion. The results of assessing the population immunity of the population of the Stavropol Territory indicate that it has not yet reached the threshold level at which a decrease in the intensity of the COVID-19 epidemic process can be expected. 

1. Smirnov V.S., Zarubaev V.V., Petlenko S.V. Biology of pathogens and control of influenza and ARVI. Saint Petersburg: Hippocrates, 2019, 334 p. (In Russian).

2. Ng L.F.P. The Virus That Changed My World PLoS Biol. 2003; 1 (3): e66. doi: 10.1371/journal.pbio.0000066.

3. Memish Z. A., Perlman S., Van Kerkhove M. D., Zumla A. Middle East respiratory syndrome Lancet. 2020;395(10229): 1063-1077. doi: 10.1016/S0140-6736 (19) 33221-0.

4. Lu H., C. Stratton W., Tang Y.-W. The Wuhan SARSCoV-2 — What’s next for China. J. Med. Virol. 2020;92(6):546- 54710.1002 / jmv.25738. doi: 10.1002/jmv.25738.

5. WHO Director-General’s remarks at the media briefing on 2019-nCoV on 11 February 2020. (Cited 15 Sep 2020) [Internet]. Available from: https://www.who.int/dg/speeches/ detail/who-director-general-s-remarks-at-the-media-briefingon-2019-ncov-on-11- february-2020 ...

6. Tay M.Z., Poh C.M., Rénia L., MacAry P.A., Ng L.F.P. The trinity of COVID-19: immunity, inflammation and intervention. Nat. Rev. Immunol. 2020: 1–12. doi: 10.1038/s41577-020-0311-8.

7. Gralinski L.E., Baric R.S. Molecular pathology of emerging coronavirus infections. J Pathol. 2015; 235 (2): 185-195. doi: 10.1002/path.4454

8. Rahman N., Basharat Z., Yousuf M., Castaldo G., Rastrelli L., Khan H. Molecules. 2020 May; 25 (10): 2271. Published online 2020 May 12. doi: 10.3390/molecules25102271

9. Vabret N., Britton GJ, Gruber C., Hegd S., Kim J., Kuksin M., Levantovsky R., Malle L., Moreira A., Park MD, Pia L., Risson E., Saffern M ., Salomé B., Selvan ME, Spindler MP, Tan J., van der Heide V., Gregory JK, Alexandropoulos K., Bhardwaj N., Brown BD, Greenbaum B., Gümüş ZH, Homann D., Horowitz A. , Kamphorst AO, Curotto de Lafaille MA, Mehandru S., Merad M., Samstein RM, The Sinai Immunology Review Project. Immunology of COVID-19: current state of the science. Immunity, 2020; 52(6): 910- 941. 2020. DOI: https://doi.org/10.1016/j.immuni.2020.05.002

10. Herroelen P.H., Martens G.A., De Smet D., Swaerts K., Decavele A.-S. Humoral Immune Response to SARS-CoV-2 Comparative Clinical Performance of Seven Commercial Serology Tests Am J Clin Pathol. 2020;154(5)610-619. doi: 10.1093/ajcp/aqaa140

11. Clemente-Suárez V. J., Hormeño-Holgado A., Jiménez M., Benitez-Agudelo J.C., Navarro-Jiménez E., Perez-Palencia N., Maestre-Serrano R., Laborde-Cárdenas C.C., TorneroAguilera J.F. Dynamics of Population Immunity Due to the Herd Effect in the COVID-19 Pandemic.Vaccines (Basel). 2020;8(2):E236. doi: 10.3390/vaccines8020236.

12. Randolph H. E., Barreiro L. B Herd Immunity: Understanding COVID-19. Immunity. 2020;52 (5):737-741. doi: 10.1016/j.immuni.2020.04.012

13. Anderson R. M., May R. M. Vaccination and herd immunity to infectious diseases Nature. 1985;318 (6044):323-329. doi: 10.1038/318323a0.

14. Popova A.Yu., Ezhlova E.B., Melnikova A.A., Bashketova N.S., Fridman R.K., Lyalina L.V., Smirnov V.S., Chkhinzheria I.G., Grechaninova T.A., Agapov K.A., Arsentyeva N.A., Bazhenova N.A., Batsunov O.K., Danilova E.M., Zueva E.V., Komkova D.V., Kuznetsova R .N., Lyubimova N.E., Markova A.N., Khamitova I.V., Lomonosova V.I., Vetrov V.V., Milichkina A.M., Dedkov V.G., Totolyan A.A. ... Population immunity to SARS-CoV-2 among the population of St. Petersburg during the COVID-19 epidemic. Problems of especially dangerous infections. 2020;3:124-130. (In Russian) DOI: 10.21055/0370-1069-2020-3-124-130.

15. Newcombe R.G. Two-Sided Confidence Intervals for the Single Proportion: Comparison of Seven Methods. Statistics in Medicine 1998;17:857-887. doi: 10.1002/(sici)1097-0258 (19980430) 17: 8 3.0.co; 2-e.

16. Hartog den G., Schepp R.M., Kuijer M., GeurtsvanKesse C., van Beek J., Rots N., Koopmans M.P.G., van der Klis F.R.M., van Binnendijk R.S. SARS-CoV-2 – Specific Antibody Detection for Seroepidemiology: A Multiplex Analysis Approach Accounting for Accurate Seroprevalence J Infect Dis. 2020;222(9):1452–1461, doi: 10.1093/infdis/jiaa479

17. Liu B. M., Yang Q.Q., Zhao L.Y., Xie W., Si X.Y. Epidemiological characteristics of COVID-19 patients in convalescence period Epidemiol Infect. 2020;148:e108. doi: 10.1017/S0950268820001181

18. Lee S., Meyler P., Mozel M., Tauh T., Merchant R. Asymptomatic carriage and transmission of SARS-CoV-2: What do we know? Can J Anaesth. 2020;67(10):1424-1430. doi: 10.1007/s12630-020-01729-x

19. Popova A.Yu., Andreeva E.E., Babura E.A., Balakhonov S.V., Bashketova N.S., Bugorkova S.A., Bulanov M.V., Valeullina N.N., Goryaev D.V., Detkovskaya N.N., Ezhlova E.B., Zaitseva N.N., Istorik O.A., Kovalchuk I.V., Kozlovskikh D.N.,. Kombarova S.Yu, Kurganova O.P., Lomovtsev A.E., Lukicheva L.A., Lyalina L.V., Melnikova A.A.,. Mikailova O.M, Noskov A.K., Noskova L.N., Oglezneva E.E., Osmolovskaya T.P., Patyashina M.A., Penkovskaya N.A., Samoilova L.V., Smirnov V.S., Stepanova T.F., Trotsenko O.E., Totolian A.A.. Peculiarities of SARSCoV-2 nucleocapsid in children during the COVID-19 epidemic of 2020. Pediatria n.a. G.N. Speransky. 2021;100 (3): 97–106. doi: 10.24110/0031-403X-2021-100-3-97-106

20. Popova A.Y., Smirnov V.S., Andreeva E.E., Babura E.A., Balakhonov S.V., Bashketova N.S., Bugorkova S.A., Bulanov M.V., Valeullina N.N., Vetrov V.V., Goryaev D.V., Detkovskaya T.N., Ezhlova E.B., Zaitseva N.N., Istorik O.A., Kovalchuk I.V., Kozlovskikh D.N., Kombarova, S.Y., Kurganova O.P., Lomovtsev, A.E., Lukicheva L.A., Lyalina L.V., Melnikova A.A., Mikailova O.M., Noskov A.K., Noskova L.N., Oglezneva E.E., Osmolovskaya T.P., Patyashina M.A. Penkovskaya N.A., Samoilova L.V., Stepanova T.F., Trotsenko O.E., Totolian A.A. SARS-CoV-2 Seroprevalence Structure of the Russian Population during the COVID-19 Pandemic. Viruses 2021, vol. 13, no 8, p.1648. https://doi.org/10.3390/v13081648. 43.

21. Ng K., Faulkner N., Cornish G., Rosa A., Earl C., Wrobel A., Benton D., Roustan C., Bolland W., Thompson R., AguaDoce A., Hobson P ., Heaney J., Rickman H., Paraskevopoulou, Houlihan SFC, K. Thomson, Sanchez E., Shin GY, Spyer MJ, Walker PA, Kjaer S, Riddell A., Beale R., Swanton C., S. Gandhi , Stockinger B., Gamblin S., McCoy LE, Cherepanov P., Nastouli E., Kassiotis G. Preexisting and de novo humoral immunity to SARS-CoV-2 in humans. Science 2020 ;370 (6522):1339-1343. DOI: 10.1126/science.abe1107

22. Rao V., Thakur S., Rao J., Arakeri G., Brennan P. A., Jadhav S., Sayeed M. S., Rao G. Mesenchymal stem cellsbridge catalyst between innate and adaptive immunity in COVID 19. Med. Hypotheses. 2020; 143: 109845. doi: 10.1016/j.mehy.2020.109845.

23. Meng Q.-S., Liu J., Wei L., Fan H.-M., Zhou X.-H., Liang X.-T. Senescent mesenchymal stem/stromal cells and restoring their cellular functions World J Stem Cells. 2020; 12(9): 966– 985. doi: 10.4252/wjsc.v12.i9.966

24. Vellas C., Delobel P., De Souto Barreto P. Izopet J. COVID-19, Virology and Geroscience: A Perspective. J. Nutr. Health Aging 2020;24:685–691. doi. 10.1007/s12603-020-1416-2

25. Tan J., Liu S., Zhuang L., Chen L., Dong M., Zhang J., Xin Y. Transmission and clinical characteristics of asymptomatic patients with SARS-CoV-2 infection Future Virol. 2020; 15(6):373–380. doi: 10.2217/fvl-2020-0087.

26. Huang A.T., Garcia-Carreras B., Hitchings M.D.T., Yang B., Katzelnick L.C., Rattigan S.M., Borgert B.A., Moreno C.A.,Solomon B.D., Trimmer-Smith L., Etienne V., RodriguezBarraquer I., Lessler J., Salje H., Burke D.S., Wesolowski A., Cummings D.A.T. A systematic review of antibody mediated immunity to coronaviruses: kinetics, correlates of protection, and association with severity. Nature Communications volume 11, Article number: 2020; 11: 4704. 10.1038/s41467-020-18450-4

27. Shirin T., Bhuiyan T.R., Charles R.K., Amin Sh., Bhuyan I., Kawser Z., Rahat A., Alam A.N., Sultana S., Aleem MA, Khan M. X., Khan S.R., LaRocque R.S., Calderwood S.B., Ryan E.T., Slater D.M., Banu S., Clemens D., Harris D.B., Flora M.S., Kadri F. Antibody responses after COVID-19 infection in patients who are mildly symptomatic or asymptomatic in Bangladesh Int. J. Infect. Dis. 2020;101:220-225. doi: 10.1016/j.ijid.2020.09.1484.