British patient had COVID-19 for 505 consecutive days, study shows

A British patient with a severely weakened immune system had COVID-19 for almost a year and a half, researchers reported, emphasizing the importance of protecting vulnerable people from coronavirus.

There is no way to know for sure if it was the longest lasting COVID-19 infection because not everyone gets tested, especially on a regular basis like this case.

But after 505 days, “it certainly seems to be the most reported infection,” said Dr. Luke Blagdon Snell, an infectious disease expert at Guy’s & St. Thomas’ NHS Foundation Trust.

Snell’s team plans to present several “persistent” COVID-19 cases at a meeting of communicable diseases in Portugal this weekend.

Their study examined which mutations occur – and whether variants develop – in people with super-long infections. It involved nine patients who tested positive for the virus for at least eight weeks. All had weakened immune systems from organ transplants, HIV, cancer or treatment for other diseases. No one was identified for privacy reasons.

Repeated tests showed that their infections lasted an average of 73 days. Two had the virus for more than a year. Earlier, researchers said the longest-known case, which was confirmed with a PCR test, lasted 335 days.

Sustained COVID-19 is rare and different from long-lasting COVID.

“For a long time with COVID, it is generally assumed that the virus has been removed from your body, but the symptoms continue,” Snell said. “With persistent infection, it represents an ongoing, active replication of the virus.”

Each time researchers tested patients, they analyzed the genetic code of the virus to make sure it was the same strain and that people did not get COVID-19 more than once. Nevertheless, genetic sequencing showed that the virus changed over time and mutated as it adapted.

The mutations were similar to those that later appeared in widespread variants, Snell said, though none of the patients gave birth to new mutants that became variants of concern. There is also no evidence that they spread the virus to others.

The person with the longest known infection tested positive in early 2020, was treated with the antiviral drug stradesiver and died sometime in 2021. Researchers declined to name the cause of death, saying the person had several other diseases.

Five patients survived. Two cleared the infection without treatment, two cleared it after treatment, and one still has COVID-19. At the last follow-up earlier this year, the patient’s infection had lasted for 412 days.

Researchers hope that more treatments will be developed to help people with persistent infections fight the virus.

“We need to be aware that there are some people who are more susceptible to these problems like persistent infection and serious illness,” Snell said.

Although persistent infections are rare, experts said there are many people with compromised immune systems who remain at risk for severe COVID-19 and who try to stay safe after governments lifted restrictions and masks began to get rid of. And it’s not always easy to know who they are, said Dr. Wesley Long, a pathologist at the Houston Methodist in Texas who was not part of the research.

“Masking in crowds is a considerate thing to do and a way we can protect others,” he said.


The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institutes Department of Science Education. AP is solely responsible for all content.

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