The United States prison population plummeted during the early months of COVID-19 but the percentage of incarcerated Black people rose, according to a new analysis of prison data.

The higher percentage of incarcerated Black people by mid-2020 was found in almost all states, and temporarily reversed a decades-long decrease in the percentage of Black people in the national prison population, report researchers.

While several factors contributed to the increase in percentage of incarcerated Black people during the height of the pandemic, researchers argue that sentencing disparities between Black and white incarcerated people may have played a major role. As court closures at the height of the pandemic slowed the admission of individuals into the prison system, the makeup of prison populations was strongly influenced by differences in sentence lengths by race.

“And disparities in sentencing is something society can do something about,” says Brandon Ogbunu, an assistant professor of ecology and evolutionary biology at Yale University and a computational biologist. Ogbunu is co-corresponding author of a paper on the findings in the journal Nature.

By the end of spring in 2020, the US prison population had fallen by 200,000 people from pre-pandemic levels. This 17% reduction in prisoner population between March 2020 and July 2021 was “the largest decarceration in American history,” Ogbunu says. Courts closed and new admissions to prisons decreased. Many states instituted early release guidelines to reduce prison populations.

Prior to the pandemic, the percentage of incarcerated Black people in US prisons had fallen to 38.9%, the lowest level in decades, as more whites without a college education were imprisoned. However, at the height of the pandemic, from March and November of 2020, the percentage of incarcerated Black people increased by almost a full percentage point.

This spike in proportion of Black people in prison was temporary in most states and approached pre-pandemic rates in early 2021.

Read the full article about incarceration during COVID by Liz Goodfellow at Futurity.