LONDON: A UK patient with a severely weakened immune system had Covid-19 for almost ayear and a half, scientists reported, underscoring the importance of protecting vulnerable people. There’s no way to know for sure whether it was the longest-lasting Covid infection because not everyone gets tested, especially on a regular basis like this case. But at 505 days, “it certainly seems to be the longest reported infection,” said Dr Luke Blagdon Snell, an infectious disease expert at the Guy’s and St. Thomas’ NHS Foundation Trust.
Snell’s team plans to present several “persistent” Covid cases at an infectious diseases meeting in Portugal this weekend. Their study investigated which mutations arise — and whether variants evolve — in people with super long infec- tions. It involved nine patients who tested positive for at least eight weeks. All had weakened immune systems from organ transplants, HIV, cancer or treatment for other illnesses.
Repeated tests showed their infections lingered for an average of 73 days. Two had the virus for more than a year. Previously, researchers said, the longest-known case that was confirmed with a PCR test lasted 335 days. Persistent Covid is rare and different from long Covid. “In long Covid, it’s generally assumed the virus has been cleared from your body but the symptoms persist,” Snell said. “With persistent infection, it represents ongoing, active replication of the virus. ” Genetic sequencing showed that the virus changed over time, mutating as it adapted.
The person with the longest known infection tested positive in early 2020, was treated with the antiviral drug remdesivir and died in 2021. Researchers declined to name the cause of death. Five patients survived. Two cleared the infection without treatment, two cleared it after treatment and one still has Covid-19. At the last followup this year, that patient’s infection had lasted 412 days.