Do you know someone with Covid? I will bet 25¢ you do! People who have avoided contracting Covid-19 for the past 2 years thought they were in the clear and bang...they awaken with body aches, a sore throat, runny nose and a positive home Covid test. They caught "The Rona."
We now have Paxlovid ( nirmatrelvir/ritonavir), the Pfizer antiviral that has been effective at keeping "at-risk" people from hospitalization and severe disease if taken within the first 48 hours of infection. There are a number of serious drug interactions with Paxlovid so it's not easy to prescribe. Your doctor needs to research each medication you are taking to make sure Paxlovid is safe for you.
Paxlovid does work and many people resolve their symptoms and test negative on home antigen tests after taking a 5 day course of the drug. But there is increasing evidence that some people, after resolving their symptoms, develop recurrent Covid symptoms 2-8 days later and then test positive. If you have symptoms and test positive, you have to assume you are infectious. It's "go back to jail" time.
The CDC issued a health advisory on May 24 about Covid-19 rebound in people who have taken Paxlovid. The rebound symptoms seem to be mild and no-one is suggesting we stop using Paxlovid in at-risk people. Especially since Paxlovid reduces risk for severe Covid and death by 46%. (Remember the most effective prevention of death from Covid is vaccination). We don't even have good evidence of how many people get rebound symptoms but by anecdotal reports it isn't rare.
Why do some patients get rebound Covid after taking Paxlovid? The two drugs that comprise Paxlovid work by blocking an enzyme that allows the virus to replicate in the body. Researchers at UC San Diego showed that the Covid virus did NOT mutate after Paxlovid treatment. That was a relief because it was the same strain and was still sensitive to the drug. The researchers suggested that there might not have been enough of the drug getting to infected cells to stop all viral replication. Since we know individuals metabolize drugs at different levels, perhaps some people need a longer duration of treatment. At this time we just don't know why rebound occurs and how to tailor treatment regimens to prevent it.
We know Paxlovid works the way it should. It prevents serious infection and death.
We don't know why some people get Covid rebound or how to prevent it.
Interesting Factoid: 100% of Covid infections are now from Omicron variants.