In a large-scale trial headed up by Dr. Putrino and his team, the oral antiviral is being studied for use in the post-viral stage in patients who test negative for acute COVID-19 but have persisting symptoms of long COVID.
Similar to monoclonal antibodies, the idea is to quell viral persistence. If patients have long COVID because they can’t clear SAR-CoV-2 from their bodies, Paxlovid could help. But unlike monoclonal antibodies that quash the virus, Paxlovid stops the virus from replicating. It’s a different mechanism with the same end goal.
It’s been a controversial treatment because it’s life-changing for some patients and ineffective for others. In addition, it can cause a range of side effects such as diarrhea, nausea, vomiting, and an impaired sense of taste. The goal of the trial is to see which patients with long COVID are most likely to benefit from the treatment.
#4: Anti-inflammatories like metformin could prove useful
Many of the inflammatory markers persistent in patients with long COVID were similarly present in patients with autoimmune diseases like rheumatoid arthritis, according to a July 2023 study published in JAMA.
The hope is that anti-inflammatory medications may be used to reduce inflammation causing long COVID symptoms. But drugs used to treat rheumatoid arthritis like abatacept and infliximabcan also have serious side effects, including increased risk for infection, flu-like symptoms, and burning of the skin.
“Powerful anti-inflammatories can change a number of pathways in the immune system,” said Grace McComsey, MD, who leads the long COVID RECOVER study at University Hospitals Health System in Cleveland, Ohio. Anti-inflammatories hold promise but, Dr. McComsey said, “some are more toxic with many side effects, so even if they work, there’s still a question about who should take them.”
Still, other anti-inflammatories that could work don’t have as many side effects. For example, a study published in The Lancet Infectious Diseases found that the diabetes drug metformin reduced a patient’s risk for long COVID up to 40% when the drug was taken during the acute stage.
Metformin, compared to other anti-inflammatories (also known as immune modulators), is an inexpensive and widely available drug with relatively few side effects compared with other medications.
#5: Serotonin levels — and selective serotonin reuptake inhibitors (SSRIs) — may be keys to unlocking long COVID
One of the most groundbreaking studies of the year came last November. A study published in the journal Cell found lower circulating serotonin levels in patents with long COVID than in those who did not have the condition. The study also found that the SSRI fluoxetine improved cognitive function in rat models infected with the virus.
Researchers found that the reduction in serotonin levels was partially caused by the body’s inability to absorb tryptophan, an amino acid that’s a precursor to serotonin. Overactivated blood platelets may also have played a role.
Michael Peluso, MD, an assistant research professor of infectious medicine at the UCSF School of Medicine, San Francisco, California, hopes to take the finding a step further, investigating whether increased serotonin levels in patients with long COVID will lead to improvements in symptoms.
“What we need now is a good clinical trial to see whether altering levels of serotonin in people with long COVID will lead to symptom relief,” Dr. Peluso said last month in an interview with this news organization.
If patients show an improvement in symptoms, then the next step is looking into whether SSRIs boost serotonin levels in patients and, as a result, reduce their symptoms.
A version of this article appeared on Medscape.com.