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At the Marion Correctional Institution in Ohio, nearly 80 percent of prisoners tested positive for COVID-19.

What COVID-19 Prison Outbreaks Could Teach Us About Herd Immunity

Prisons turn out to be a key place to study how coronavirus spreads and how immunity to it works.

As states unevenly begin to reopen, researchers are scrambling to learn more about the coronavirus and “herd immunity.” That is when a large enough portion of the public has contracted the disease and developed antibodies so that it restrains the spread of the virus.

Prisons, it turns out, may be a key place to study the nature of this virus—including how it transmits and how immunity to it works. Because while antibody rates for the general public, estimated between 1 and 20 percent in most places, remain far too low for herd immunity to kick in, it’s an entirely different story in a number of prisons. At the Marion Correctional Institution in Ohio, nearly 80 percent of prisoners have tested positive for the disease. At the Lompoc federal prison in Santa Barbara, California, that number is around 74 percent. At one dorm in the Elyan Hunt Correctional facility in Louisiana, 192 out of roughly 195 women tested positive.

“There is sort of a natural experiment happening without anybody having to plan it, that we should be able to get data from and try and understand,” said Nina Fefferman, a mathematical modeler at the University of Tennessee.

That’s exactly what researchers from at least one university are trying to do. Joseph Tien, an applied mathematician at Ohio State University, said his team is talking with state officials in Ohio to get data from the Marion outbreak to model how coronavirus transmission there happened. He and other researchers said as valuable as studying prisons could be, they are also paying close attention to the fraught nature and barbarous history of medical research on incarcerated people.

Marion prison, an hour north of Columbus, has seen one of the nation’s most dramatic COVID-19 outbreaks. More than 2,000 prisoners tested positive and at least 13 died. In a letter published in The New York Times, a man incarcerated at Marion described tending to an infected friend with weakness, fatigue, vertigo and difficulty breathing. “With the symptoms seeming to linger and even reoccur, I am eager to be retested. It has been over 14 days since the tests. We should be negative by now. I am concerned that we are reinfecting each other,” the man wrote.

That is the type of question Tien’s team hopes to answer, armed with the testing results. “There’s a moral obligation to use this data if it can help us figure out how to slow the spread in other prisons or intervene once an outbreak has begun,” Tien said.

There may be lessons for other similar spaces too. “Here's a population where it's enclosed and there's difficulties with social distancing. So, the data that have already been collected can offer insights into what actually is the transmissibility of the disease in close quarters,” Tien said.

The Marion outbreak may also offer Tien’s team and others an early, anecdotal look at what could happen in the general public as social distancing measures are relaxed. It might also help answer how many people need to be infected and recover to trigger herd immunity.

“It might have pretty big implications for what your odds are of actually stopping the disease down the road, if we're fortunate enough to be able to develop a vaccine,” Tien said. “It could help establish an estimate of say, 80 percent coverage needed to stop the virus, versus 95 percent or 99 percent coverage.”

Although new scientific studies on COVID-19 are being published at a breakneck pace, there is still no consensus on how immunity works with coronavirus, said Jay Bhattacharya, a professor of medicine at Stanford University. “If it behaves like other coronaviruses, infection will generate some immunity, that will last for awhile and give you at least partial protection—and that will eventually fade over time,” he said.

How long that protection might last is, to this point, impossible to know for a virus that was only discovered six months ago, experts said. But the crowded conditions and lack of protection equipment that made prisons disproportionately vulnerable to outbreaks mean they are a good bet to be the places where we find out, said Susan Hassig, an epidemiologist at the Tulane School of Public Health and Tropical Medicine.

“If most of them stay in place, and there's another outbreak in three months, we know that immunity doesn't exist, whether it's a formal study or not,” she said of the prisoners at Elyan Hunt, where at least two people have died after contracting COVID-19.

Whether research inside prisons produces results that help decide broader public health measures remains to be seen, said Fefferman, the Tennessee researcher who has spent much of the last 15 years modeling infectious disease. She said the intuition to look into prison outbreaks is “absolutely correct,” but cautioned that there are many caveats that make it challenging or even impossible to apply those findings to the general public. Prisoners, for example, are disproportionately men, non-white and have weaker inmune systems than the broader U.S. population.

“Prisons are going to be the most controlled data, early on, for populations being exposed, but there are so many confounding factors that we don't understand yet about what coronavirus does in the body, that it's not as clear cut how to figure out how that translates beyond the prison system,” she said.

Fefferman is hopeful that observing the outbreaks in prisons could lead to more effective treatments for incarcerated people who may get COVID-19 in the future. For example, some early studies in the general population have suggested vitamin D may help the immune system fight the infection, but many prisoners don’t have enough vitamin D.

“If we're seeing much more severe cases, but only in the people who've been incarcerated for more than six months, then we can start considering: ‘maybe some of this is stress or vitamin D or nutrition’ in ways that may suggest slightly different medical interventions,” Fefferman said.

In a recent study, Fefferman found that because of the nature of infectious disease like COVID-19, and the near impossibility of social distancing in local jails, “large scale reductions in arrest and speeding of releases are likely to save the lives of incarcerated people, staff and the community at large.”

The Marion analysis would only use data that has already been collected—fairly similar to data being compiled by The Marshall Project—in an effort to work in the “least intrusive way possible,” Tien said. He noted the ethical challenges of working with prison populations in any capacity, a concern that all the researchers who spoke to The Marshall Project shared. Even when studies are voluntary, it is highly likely that prisoners would fear coercion or retribution for non-participation, experts said. U.S. prisons have been the site of ghastly experiments such as Pennsylvania’s Holmesburg prison, where inmates in the 1950s and 60s were exposed to chemicals, cosmetics, untested drugs and bacteria in order to allow medical researchers to study their effects. At Stateville prison in Illinois—the site of another coronavirus hotspot— prisoners were intentionally infected with malaria over three decades, so scientists could gauge the effectiveness of medical treatments for the disease.

But even if most researchers never lay a finger on prison-specific data about COVID-19, Hassig said there are already important public health lessons to be learned from prison outbreaks. One of the most confounding aspects of the high coronavirus rates in prisons is that most people testing positive haven’t shown symptoms. At Marion, 95 percent of those testing positive were asymptomatic. At Elyan Hunt prison in Louisiana, that was true for more than two-thirds. That data has led some Louisiana researchers to believe that the actual infection rate in the general community may be much higher than official numbers indicate.

“From a public health perspective it’s critical to be using any information we can garner from whatever population, in this case, to drive home the fact that you could be feeling just fine yet shedding virus,” Hassig said.

Jamiles Lartey Twitter Email is a New Orleans-based staff writer for The Marshall Project. Previously, he worked as a reporter for the Guardian covering issues of criminal justice, race and policing. Jamiles was a member of the team behind the award-winning online database “The Counted,” tracking police violence in 2015 and 2016. In 2016, he was named “Michael J. Feeney Emerging Journalist of the Year” by the National Association of Black Journalists.