Doctors in the UK have called for urgent new treatments to clear persistent Covid infections after identifying the world’s first person known to have harbored the virus for more than a year.
The patient, who had a weakened immune system, caught the virus in 2020 and was positive for Covid for 505 days before he died. Previously, the longest known case of Covid, confirmed by PCR, had survived cancer in the United States for 40 years, which was positive for 335 days.
Researchers at King’s College London and the Guy’s and St. Thomas’ NHS Foundation followed nine patients with persistent Covid to see how the virus developed during their infection. All patients had a weakened immune system due to organ transplantation, HIV, cancer or therapies for other diseases.
Infections usually last about 10 weeks, but two patients have had the virus for more than a year. In addition to the patient who was infected for 505 days, the latter has so far tested positive for 412 days and may exceed the 505-day record at his next follow-up. Last summer, doctors in Bristol revealed that a 72-year-old patient, Dave Smith, had tested positive for nearly 10 months.
Patients with weakened immune systems are particularly vulnerable to prolonged Covid infections. In the latest study, four of the nine patients died, with Covid contributing to perhaps a third to half of those deaths. Persistent infections may also be a source of new variants of Covid, as the virus acquires new mutations as it develops in the patient.
“These people seem to have a very bad result when they have a persistent infection,” said Dr. Luke Blagdon Snell, a clinical research associate at Guy’s. “There is an urgent need to develop better treatments to clear infections for the benefit of the patient. There may also be additional benefits in preventing variants, but this is not yet clear. “
Genetic analysis has revealed that in five of the nine patients, the virus has acquired at least one mutation found in anxiety variants that tend to cause large waves of disease. The virus, obtained from a patient who has been infected for 505 days, carries 10 mutations that occur separately in several major variants, including Alpha, Gamma and Omicron.
Many scientists suspect that some variants of anxiety, such as Alpha, have arisen in patients with persistent infections, but other sources of new variants are possible, such as animals that infect the virus and then transmit it back to humans. Snell said none of the mutated viruses found in patients in the study appeared to have spread beyond infected individuals.
One patient in the study probably had a rare “occult” infection, which means that he tested negative for PCR for Covid, even though he has a continuing infection. After falling ill with the Alpha variant in 2021, the patient’s symptoms subsided and the test was negative several times, but later they saw that the Alpha variant recovered and caused additional symptoms, although the variant was no longer present in the United Kingdom. The patient did not travel abroad. The virus may have been lurking deep in their lungs, where nasal and throat swabs can’t detect it, Snell said.
Dr Gaia Nebbia, co-author of the study, said new treatment strategies were “urgently needed” to help patients clear up persistent infections. “It can also prevent options,” she said. The work will be presented at the European Congress of Clinical Microbiology and Infectious Diseases in Lisbon on Friday,
Paul Hunter, a professor of medicine at the University of East Anglia who was not involved in the study, said there may be people who never clear their Covid infections. While antiviral drugs and antibody therapies help many patients, antibody treatment in clinics today is less effective against Omicron than previous options. “It would be no less important to manage the root cause of immune suppression in the hope that a person’s immune system can recover,” Hunter said.
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