A patient who tested positive for Covid-19 for 411 days was finally cured by a combination of antibodies, British researchers announced on Friday, who had to genetically analyze his virus to find the right response.
A persistent infection, different from a long Covid or repeated episodes of the disease, can strike a small number of patients with already weakened immune systems.
They can test positive for months or even years, the infection “rumbling all the time”, explained Luke Blagdon Snell, infectious disease specialist at the Guy and St Thomas foundation of the British public health service, the NHS.
In about half, symptoms persist, such as lung inflammation, he told theAFPadding that many unknowns remained on the Covid.
Several treatments tested without success
In a study published in the journal Clinical Infectious Diseases, a team of researchers, led by Luke Blagdon Snell, describes how a 59-year-old man finally overcame his infection after more than 13 months.
This patient, with an immune system weakened by a kidney transplant, contracted Covid in December 2020 and tested continuously positive until January 2022.
To find out if he had been contaminated several times or if he had a persistent infection, the researchers used rapid genetic analysis (nanopore sequencing). The results proved the infection.
So the researchers administered a combination of monoclonal antibodies, casirivimab and imdevimab, which apparently worked.
But this success is linked to the fact that the patient was infected with an old version of the coronavirus. This variant, dominant in late 2020, has since been superseded by other incarnations.
Gold, “the new variants […] are resistant to all antibodies available in the UK, EU, and even the US”notes Luke Blagdon Snell.
This is evidenced by another case, which caused more difficulties for the scientist’s team and which is detailed in a second study, not yet reviewed by peers.
Researchers unsuccessfully tested existing antibody treatments on a critically ill 60-year-old man who had been infected since April.
Suddenly, the team mixed two antiviral treatments not previously combined – Paxlovid and remdesivir – and administered them to the unconscious patient via a nasogastric tube. These treatments were given twice as long as usually recommended.
The Covid infection eventually disappeared, the man was cured, giving hope for a new treatment option for patients with persistent and severe Covid.
In April, these same researchers announced, at the European Congress of Microbiology and Infectious Diseases, the longest known persistent infection with Covid-19, in a man who tested positive for 505 days, until his death.