People experiencing homelessness have high rates of COVID-19 reinfection, further endangering the health of an already vulnerable population, according to a study published Friday in the journal BMC Infectious Diseases.
Homeless people in Toronto who had had COVID-19 were more than twice as likely to get it again as people with housing, said lead author Lucie Richard, a senior research associate at the MAP Center for Urban Health Solutions at St. Michael’s Hospital.
The higher reinfection rates are likely due to increased exposure to the virus, as homeless people are “forced to reside in congregated, crowded shared environments that are high in transmission,” Richard said.
They are also more likely than the general public to have underlying health conditions that make them more vulnerable to illness, she said.
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Researchers followed 381 homeless people who had previously been infected with COVID-19 for about a year. The study period lasted from June 2021 to October 2022 – a period that began when the Delta variant was dominant and ended when the more infectious Omicron variant took hold.
They used PCR and rapid antigen tests to confirm reinfections among the homeless group, compared it to existing data on the reinfection rate in the general population, and found it to be twice as high.
But the researchers went further and also took blood samples provided by unhoused study participants. These serological tests detected even more COVID reinfections than PCR and rapid antigen tests.
This finding confirmed that PCR data underestimated infections, Richard said, noting that more serological testing should be done in the general population to get a more accurate read on the extent of COVID reinfections in the era of COVID-19. ‘Omicron and its sub-variants.
“Omicron shows up and all of a sudden everyone who was already infected is reinfected. And people who were never infected were infected for the first time,” Richard said.
When blood test results were taken into account, researchers found that about a third of the homeless participants had been reinfected with COVID-19 at least once.
Multiple infections can increase the risk of negative health consequences in the future, including long COVID, Richard said.
Results apply in different cities
Although more reinfections would likely also be detected in the general population if blood tests were used, Richard and other experts not involved in the study agree that the risk of reinfection for people experiencing homelessness would still be disproportionately higher.
“We’re seeing some of these trends work clinically and … from a patient care perspective,” said Dr. Andrew Boozary, a primary care physician and executive director of the University Network’s Gattuso Center for Social Medicine. Toronto Health Centre. .
“You can do everything you can and try to avoid COVID. But if you’re in a shelter where you’re filled with a much higher number of people, the air quality or conditions are different.” , said Boozary, who was not involved in the study.
“This (research) is in line with previous studies showing that there were mortality rates five times higher for unhoused people during COVID waves than for the general public,” he said. he declares.
Although the study was conducted in Toronto, the results would apply to other cities as well, said Dr. Brian Conway, president and medical director of the Vancouver Infectious Diseases Centre.
“It’s a warning that we need to take care of our inner cities, especially our homeless (people),” said Conway, who was also not involved in the study.
“(In Vancouver) we have more homeless people. We have more people living in shelters and in our downtown, the people who are housed are very inadequately housed in substandard housing,” he said. he declared.
Boozary and Conway shared Richard’s concern that higher rates of COVID reinfection would lead to a higher risk of long COVID among the homeless.
“When you look at the prospect of reinfection and then the greater likelihood of long COVID, you’re just compounding the disparities for people surviving homelessness,” Boozary said.
“We know that there is already a higher rate of chronic illnesses and chronic illnesses that unhoused people have to deal with. And then when you add in this very devastating long COVID syndrome… it’s devastating” , did he declare.
Conway said it’s important to give homeless people easy access to the latest COVID-19 vaccine targeting the XBB subvariant to help reduce reinfection — and it’s also critical to address the housing issue.
“It’s not us and them. It’s us and us. And these people are us, and they’re obviously living in circumstances that seem to cause them to repeatedly reacquire COVID. And we owe it to them to try to change these conditions,” he said.