LONDON: British researchers believe they have documented the oldest known COVID-19 infection, in a patient who tested positive for a total of 505 days before his death.
The previous record for persistent infection, rather than repeated COVID episodes, is thought to be 335 days, the team from King’s College London and Guy’s and St Thomas’ NHS Foundation Trust said.
One of the study’s co-authors, consultant virologist Gaia Nebbia, said that in mid-2020 the unidentified person was diagnosed with respiratory symptoms that later improved.
But then they tested positive about 45 times before attending the hospital until their death.
Nebbia said persistent infection with SARS-CoV-2, the virus that causes COVID-19, has been described in patients with weakened immune systems.
She and her team studied how the virus from nine COVID patients in London changed over time and concluded that new variants can occur in immunocompromised patients.
“This is one of the hypotheses for the appearance of variants,” Nebbia told AFP.
“Regular sampling and genetic analysis of the virus showed that five of the nine patients developed at least one mutation seen in variants of concern.
“Some people developed multiple mutations associated with variants of concern, such as the Alpha, Delta and Omicron variants.
“However, none of the individuals in our work developed new variants that became widespread variants of concern.”
Of the nine immunocompromised patients who tested positive for at least eight weeks, infections persisted for an average of 73 days.
But two patients had persistent infections for more than a year.
All of the patients had weakened immune systems due to organ transplantation, HIV, cancer, or other medical therapies. They were studied between March 2020 and December of last year.
Of the nine, five survived. Two of the five recovered without treatment and another two recovered after antibody and antiviral therapy.
The fifth individual was still infected at his last follow-up exam in early 2022, even after treatment, and had COVID for 412 days.
If they test positive at their next appointment, they will break the record of 505 days, the researchers said.
Nebbia said the situation demonstrated the urgent need for new treatments to help immunocompromised patients recover.
The findings will be presented at the European Congress of Clinical Microbiology and Infectious Diseases in Lisbon, which starts on Saturday.