Peer-reviewedCC BY-NCSocial science & medicine (1982)
Exceptionally low mortality despite widespread COVID-19 infection among Indigenous Tsimane and Moseten of Bolivia
21 affiliations
- 1Unité des Virus Émergents (UVE: Aix-Marseille Univ, Università di Corsica, IRD 190, Inserm 1207, IRBA), France.
- 2Gran Consejo Tsimane, San Borja, Bolivia.
- 3Tsimane Health and Life History Project, San Borja, Bolivia.
- 4Universidad Mayor de San Simon, Cochabamba, Bolivia.
- 5School of Collective Intelligence, Mohammed VI Polytechnic University, Rabat, Morocco
- 6School of Human Evolution and Social Change and Institute of Human Origins, Arizona State University, Tempe, USA.
- 7Center for Evolution and Medicine, Arizona State University, Tempe, USA
- 8Economic Science Institute, Argyos School of Business and Economics, Chapman University, Orange, USA.
- 9Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- 10Leonard Davis School of Gerontology, University of Southern California, Los Angeles, USA.
- 11Center for Economic and Social Research, University of Southern California, Los Angeles, USA.
- 12Department of Anthropology, University of Utah, Salt Lake City, USA
- 13Department of Biological Sciences, Vanderbilt University, Nashville, USA
- 14Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, USA
- 15Department of Pediatrics, University of California Irvine School of Medicine, Irvine, USA
- 16Department of Anthropology, University of California Santa Barbara, Santa Barbara, USA
- 17School of Collective Intelligence, Universite Mohammed VI Polytechnique, Rabat, Morocco
- 18Department of Social and Behavioral Sciences, Toulouse School of Economics, and Institute for Advanced Study in Toulouse, Toulouse, France
- 19Division of Cardiology, University of California, Irvine, USA
- 20Department of Cardiology, Saint Luke’s Mid America Heart Institute, Kansas City, USA
- 21See ‘Research Team Membership ’ in Supplementary Materials .
Abstract
We report on the prevalence of and mortality from SARS-CoV-2 among the Tsimane and Moseten, two Indigenous subsistence groups in Bolivian Amazonia, and show that they evidence the lowest infection fatality rate ever reported. These populations have minimal access to medical care, a history of high parasite and pathogen exposures, and upregulated immune responses compared to industrialized populations. Between July and December of 2020, and again March - May of 2021, 85.4% of the Tsimane population aged 17+ were interviewed, and 42.0% provided blood samples. Among the Moseten aged 17+, 38.3% were interviewed and 38.6% provided blood samples. Blood samples were analyzed for SARS-CoV-2 antibodies with a mix of point-of-care IgG/IgM and ELISA with seroneutralization. The pandemic experience of these groups during the initial 2020 wave contrasts sharply with that observed in more industrialized contexts: while 71% and 63% of the Tsimane and Moseten populations were infected with SARS-CoV-2, mortality was minimal, with infection fatality ratios of 0.009% and 0.095%, respectively. The mortality rate for the Tsimane is 1/23rd the expectation based on rates observed elsewhere in the world. Disease severity-as measured by length of illness, ELISA antibody titers, and virus neutralizing test titers-did not increase markedly with age. We propose that low fatality, despite high transmissibility and non-negligible severity, may be due to a more vigorous and effective immune response to infection, with implications for future global pandemics.
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BibTeX
@article{inchauste2026exceptionally,
title = {{Exceptionally low mortality despite widespread COVID-19 infection among Indigenous Tsimane and Moseten of Bolivia}},
author = {Lucia Inchauste and Xavier de Lamballerie and Stepháne Priet and Maguin Gutierrez Cayuba and Juan Copajira Adrian and Daniel Eid Rodriguez and Raul Quispe Gutierrez and Sarah Alami and Jacob E. Aronoff and Kenneth Beutow and Daniel K. Cummings and Bret A. Beheim and Caleb E. Finch and Margaret Gatz and Suhail Ghafoor and Thomas S. Kraft and Amanda J. Lea and Wendy J. Mack and David E. Michalik and M. Katherine Sayre and Edmond Seabright and Jonathan Stieglitz and Gregory S. Thomas and Randall C. Thompson and Benjamin C. Trumble and Tsimane Health and Life History Project and HORUS Research Team and Hillard S. Kaplan and Michael D. Gurven and Paul L. Hooper},
journal = {Social science \& medicine (1982)},
year = {2026},
month = jun,
doi = {10.1016/j.socscimed.2026.119493},
url = {https://doi.org/10.1016/j.socscimed.2026.119493},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Exceptionally low mortality despite widespread COVID-19 infection among Indigenous Tsimane and Moseten of Bolivia
AU - Lucia Inchauste
AU - Xavier de Lamballerie
AU - Stepháne Priet
AU - Maguin Gutierrez Cayuba
AU - Juan Copajira Adrian
AU - Daniel Eid Rodriguez
AU - Raul Quispe Gutierrez
AU - Sarah Alami
AU - Jacob E. Aronoff
AU - Kenneth Beutow
AU - Daniel K. Cummings
AU - Bret A. Beheim
AU - Caleb E. Finch
AU - Margaret Gatz
AU - Suhail Ghafoor
AU - Thomas S. Kraft
AU - Amanda J. Lea
AU - Wendy J. Mack
AU - David E. Michalik
AU - M. Katherine Sayre
AU - Edmond Seabright
AU - Jonathan Stieglitz
AU - Gregory S. Thomas
AU - Randall C. Thompson
AU - Benjamin C. Trumble
AU - Tsimane Health and Life History Project
AU - HORUS Research Team
AU - Hillard S. Kaplan
AU - Michael D. Gurven
AU - Paul L. Hooper
PY - 2026
DA - 2026/06/17
JO - Social science & medicine (1982)
DO - 10.1016/j.socscimed.2026.119493
UR - https://doi.org/10.1016/j.socscimed.2026.119493
AB - We report on the prevalence of and mortality from SARS-CoV-2 among the Tsimane and Moseten, two Indigenous subsistence groups in Bolivian Amazonia, and show that they evidence the lowest infection fatality rate ever reported. These populations have minimal access to medical care, a history of high parasite and pathogen exposures, and upregulated immune responses compared to industrialized populations. Between July and December of 2020, and again March - May of 2021, 85.4% of the Tsimane population aged 17+ were interviewed, and 42.0% provided blood samples. Among the Moseten aged 17+, 38.3% were interviewed and 38.6% provided blood samples. Blood samples were analyzed for SARS-CoV-2 antibodies with a mix of point-of-care IgG/IgM and ELISA with seroneutralization. The pandemic experience of these groups during the initial 2020 wave contrasts sharply with that observed in more industrialized contexts: while 71% and 63% of the Tsimane and Moseten populations were infected with SARS-CoV-2, mortality was minimal, with infection fatality ratios of 0.009% and 0.095%, respectively. The mortality rate for the Tsimane is 1/23rd the expectation based on rates observed elsewhere in the world. Disease severity-as measured by length of illness, ELISA antibody titers, and virus neutralizing test titers-did not increase markedly with age. We propose that low fatality, despite high transmissibility and non-negligible severity, may be due to a more vigorous and effective immune response to infection, with implications for future global pandemics.
SN - 0277-9536
SN - 1873-5347
ER -