Researchers Study Why Bolivian Amazon Communities Had Extremely Low COVID Death Rates

Two Indigenous communities have death rates of 0.009% and 0.095% despite being infected at high rates.

Aug. 21, 2026

2 min read

Key Highlights

The Tsimane and Moseten communities experienced extremely low COVID-19 death rates despite high infection prevalence.
Their immune systems may be primed by constant exposure to parasites and infectious diseases, leading to a robust immune response.
Low levels of cardiovascular diseases, inflammation, and diabetes contributed to milder COVID-19 symptoms and outcomes.
Blood tests showed elevated COVID-specific antibodies, indicating strong immune activation possibly due to environmental factors.
Understanding these immune responses could inform strategies for managing future pandemics and infectious diseases.

A new study published in Social Science & Medicine looks into why two Indigenous groups in Bolivian Amazon had extremely low death rates during the COVID-19 pandemic. CIDRAP has the news.

In the Tsimane community, deaths were only at a rate of 0.009%, and among the Moseten community, there was a death rate of 0.095%.

There was concern at the beginning of the pandemic that these groups may be hit harder due to historical trends when Indigenous groups are hit by introduced pathogens. Other Indigenous groups experienced high death rates from COVID. Indeed, the virus quickly spread to both of the groups studied, to 71.4% of the Tsimane sampled and 63% of the Moseten.

The infected people "never quite got to that second stage [of infection] where it enters your lungs." They also tended to have remarkably low levels of the cardiovascular diseases, inflammation, and diabetes that can lead to severe complications from infection. However, the groups tend to have high rates of parasitism and infectious diseases like tuberculosis.

Blood tests showed that COVID-specific antibodies were more than double those measured in a French cohort during the same COVID wave. The groups' persistent exposure to pathogens amid a lack of sanitation and abundant parasites and bacterial infections could explain why their bodies were ready to mount a robust immune response. A better understanding of these factors will be helpful for future pandemics and pathogens.