Mayo Clinic researchers studied the outcomes of 483 high-risk patients treated for COVID with a five-day oral regimen of Paxlovid, a combination of nirmatrelvir and ritonavir. Only a handful developed COVID rebound symptoms, something which the researchers say needs further investigation. Their findings appear in the journal Clinical Infectious Diseases.
All of the patients benefited from Paxlovid and recovered, including the patients who developed rebound symptoms, which were generally mild.
“We found that rebound phenomenon was uncommon in this group of patients,” says senior author Aditya Shah, MBBS, an infectious diseases physician and researcher at Mayo Clinic. “The four individuals who experienced rebound [symptoms] represent only 0.8% of the group, and all of them recovered quickly without additional COVID-directed therapy.”
Most of the patients had been vaccinated, and many had received booster vaccinations. The median age was 63. While these patients were high-risk for COVID, none was immunocompromised. Only two patients were admitted to the hospital, and it was for reasons other than COVID.
The study focussed on four patients with rebound symptoms:
- A 75-year-old man with coronary artery disease who had increased cough and muscle aches 19 days after treatment.
- A 40-year-old woman with obesity, hypertension and kidney disease who developed fatigue and sore throat six days after treatment.
- A 69-year-old man with hypertension and obesity who exhibited nasal discharge and cough 10 days following therapy.
- A 70-year-old man with a history of prostate cancer, obesity, hypertension and high cholesterol, who developed significant sinus congestion 10 days after treatment.
Why did some rebound?
Researchers think one explanation could be that a replication of SARS-CoV-2 could have triggered a secondary immune response, which showed up as mild COVID symptoms. This question could be answered by prospective studies could answer the question. They also note that all four patients with rebound symptoms had many serious health problems known as comorbidities — a factor shown to complicate recoveries. And all four patients had been vaccinated more than 90 days before becoming infected with COVI.
Source: Mayo Clinic