Progression of COVID-19 in six South American countries with different vaccination coverage

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Jose-Luis Sagripanti Daniel R. Aquilano


COVID-19 seems to have progressed under two general assumptions: a) every new variant of SARS-Co V-2 should bear the worst consequences, thus justifying extension of government-mandated lock-downs, school and border closures, face mask wearing and other restrictive measures and b) that hastily developed experimental vaccines employing novel technologies would quickly and efficiently stop the pandemic by protecting from infection or, at the very least, by preventing complications and death. We tested these two hypotheses by analyzing the epidemiological data officially released by the governments of six countries in South America. We found that vaccination failed to prevent contagion by Omicron or by previous variants of SARS-Co V-2. Mortality has decreased with time since the start of global COVID-19 in early 2020 with Omicron showing the lowest mortality to date. This finding cursorily agreed with a beneficial effect of vaccination in each individual country but failed when countries with similar mortalities and different vaccination rates were analyzed. Thus, the slight but continued reduction in mortality through the duration of the pandemic and sharp decrease with Omicron do not correlate with the level of national vaccination among the countries studied. A more plausible explanation for the decrease in mortality through time is the natural attenuation of SARS-Co V-2 from successive passage through millions of susceptible and healthy hosts, as dictated by well-established principles of virology, immunology, and vaccinology dating at least from the mid 1950’s. The failure to prevent infection or to substantially reduce mortality as reported here should raise questions about the value of the massive vaccination campaigns in South America, particularly, considering the potential risks of adverse reactions (still to be fully determined) to experimental vaccines and the considerable cost to the stressed national economies of the region.

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SAGRIPANTI, Jose-Luis; AQUILANO, Daniel R.. Progression of COVID-19 in six South American countries with different vaccination coverage. Medical Research Archives, [S.l.], v. 10, n. 3, mar. 2022. ISSN 2375-1924. Available at: <>. Date accessed: 28 nov. 2022. doi:
Research Articles


1. Sabin AB. Present status of attenuated live-virus poliomyelitis vaccine. 1956. JAMA 1956: 162, 1589-1596. PMID: 13376323 DOI: 10.1001/jama.1956.02970350005002.

2. Dull B and Wherle PF. Prevention of communicable diseases. In: Communicable and infectious diseases7th Edition. 1972:20-31. F.H. Top and P.F. Wherle (Editors). C.V. Mosby Co. Saint Louis.

3. Murphy BR and Chanock RM. Immunization against viruses. In: Virology 2nd Edition.1990:469-502. B.N. Fields and D.M. Knipe (Editors).Raven Press, New York

4. BBCNews. Variante andina (lambda): qué se sabe de la nueva variante que circula en varios países de Sudamérica y por qué preocupa a la OMS. (Lambda variant: what is known about this variant present in several South American countries).June 16, 2021. Accessed January7, 2022. Accessed January 9, 2022

5. Argentine Government Report. Proyecto Argentino Interinstitucional de Genómica. (Argentine Interinstitutional Project of Genomics). June 6, 2021. Accessed December 20, 2021

6. Forchette L, Sabastian W, and Liu TA. Comprehensive review of COVID-19 virology, vaccines, variants and therapeutics. Current Medical Sci. 2021. PMID: 34241776 PMCID: PMC8267225 DOI: 10.1007/s11596-021-2395-1. Accessed December 5, 2021

7. World Health Organization. Update on Omicron. Release dated 28 November 2021. Accessed November 25, 2021

8. BBC News. Omicron: first confirmed cases in Latin America (Ómicron: confirman los primeros casos de la nueva variante del coronavirus en América Latina). November 30, 2021. Accessed December 5, 2021

9. Ministery of Health of Argentina. Argentine Government Report on Vaccination Campaign. Updated daily. Accessed February 5, 2022

10. Ministery of Health and Sports of Bolivia. Bolivian government report on the vaccination campaign. Updated daily. Accessed February 2, 2022

11. Ministery of Health of Brazil. Patria vacinada, Brazilian government report on the vaccination campaign. Accessed February 2, 2022

12. Chilean Government Report. Plan Nacional de Vacunación COVID-19 (National Plan of Vaccination COVID-19). Updated daily. Accessed February 2, 2022

13. Ministery of of Public Health and Social Welfare of Paraguay. Government report on the vaccination campaign. Updated daily. Available on line at: February 2, 2022

14. Ministery of Public Health of Uruguay.Plan Ncional de Vacunación COVID-19, Uruguay se vacuna (National Plan of Vaccination: Uruguay vaccinates).Updated daily. Accessed February 2, 2022

15. Sagripanti JL, and Lytle CD (2020) Estimated inactivation of coronaviruses by solar radiation with special reference to COVID-19. Photochemistry and Photobiology 96, 731-737. doi: 10.1111/php.13293. Epub 2020 Jul 9.

16. Sagripanti JL. Seasonality and progression of COVID-19 among countries with or without lock-downs.Open J Epidemiol. doi: 10.4236/ojepi.2021.113027.

17. Sagripanti JL and Aquilano DR. Progression of COVID-19 under the highly restrictive measures imposed in Argentina. J Public Health Res. 2022, 11:2490

18. World Health Organization. 10 Vaccines approved for use by WHO. Accessed February 2, 2022

19. World Health Organization. COVID-19 advice for the public: Getting vaccinated. Accessed January 25, 2022

20. US Food and Drug Administration. 2022. COVID-19 vaccines authorized for emergency use or FDA-Approved. January 23, 2022

21. Centers for Disease Control and Prevention. CDC Science Brief: COVID-19 vaccines and vaccination. Summary of Recent Changes.,interrupting%20chains%20of%20transmission. Accessed January 25, 2022

22. Ministery of Health of Argentina. Cuales vacunas estamos aplicando en el pais? [Which vaccines are available?]. Accessed December 15, 2021

23. Panamerican Health Organization. Bolivia se destaca por el proceso de introducción de las vacunas anti-COVID-19. [Bolivia ahead in introducing COVID-19 vaccines] Accessed January 5, 2022

24. Agencia Brasil. Brasil supera los 110 millones de dosis de vacunas aplicadas. [Brazil reaches 110 million administered vaccines]. September 7, Accessed November 20, 2021

25. Ministry of Health of Chile. Vacunas contra SARS- CoV-2 utilizadas en Chile mantienen altos niveles de efectividad para evitar hospitalización, ingreso a UCI y muerte. [Vaccines against SARS-Co V-2 in Chile have high effectiveness in preventing hospitalization, and death] August 3, 2021 Accessed November 20, 2021

26. El Surti. El estado de las vacunas anti-covid en Paraguay. [State of anti COVID vaccines in Paraguay]. October 15, 2021. November 20, 2021

27. Ministery of Public Health of Uruguay. ¿Qué vacunas llegarán a Uruguay primero? [Which vaccines are coming to Uruguay?] February 23, 2021. Accessed November 20, 2021

28. Roser M, Ortiz-Espina E, Ritchie H, Hasell J, Giattino C, Herre B, Dattani S. Our World in Data. Coronavirus pandemic (COVID-19). 2022. Updated daily. February 7, 2022

29. Ioannidis, JPA. Infection Fatality Rate of COVID-19 Inferred from Seroprevalence Data. Bulletin of the World Health Organization 2020. Accessed October 17, 2021

30. United Nations. World Population Prospects - United Nations population estimates and projections. 2019. Accessed January 5, 2022

31. Soper D. Analytics Calculators. Significance of the Difference between Two Slopes. Accessed January 31, 2022.

32. Good Calculators. Accessed January 31, 2022.

33. Melnick JL. Enteroviruses: Poliovirus, coxsackieviruses, echoviruses and enteroviruses. Pages 549-605. In Virology 2nd. B.N. Fields and D.M. Knipe (Editors). 1990. Raven Press, New York.

34. Sabin AB. 1957. Properties and behavior of orally administered attenuated poliovirus vaccine. JAMA 164, 1216-1223.PMID: 13438685.Also available at:

35. Murphy BR and Chanock RM. Immunization against viral diseases. In Knipe DM and Howley PM (Editors) Fields Virology 4th Edition pages 435-467. 2001. Lippincott Williams & Wilkins. Philadelphia.