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, with the infection "rumbling all the time", explained Luke Blagdon Snell, an 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 AFP, adding that many unknowns remained on the Covid.
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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.
Monoclonal antibodies acted on an ancient variant
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.
The researchers therefore administered a combination of monoclonal antibodies, casirivimab and imdevimab, manufactured by the company Regeneron.
And it 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This variant, dominant at the end of 2020, has since been replaced by other variants.
However, “the new variants (…) are resistant to all the antibodies available in the United Kingdom, in the EU, and even in the United States”, notes Luke Blagdon Snell.
Hope for newer variants
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.
Our case suggesting combination of remdesivir and Paxlovid may act synergistically to treat chronic COVID/persistent SARS-CoV-2.
Joining two cases from USA published in past week.
@GaiaNebbia @jonathanCIDR @samd2000 #covid https://t.co/Up6FZ5pzNk
— Luke Blagdon Snell (@lukebsnell) November 3, 2022
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.
