After clinical trials showed Paxlovid could reduce the risk of hospitalization and death from COVID-19 by 89%, the drug was made available under an emergency use authorization from the US Food and Drug Administration on December 2021.
The treatment includes two drugs, nirmatrelvir and ritonavir, that work together to stop SARS-CoV-2 by blocking an enzyme that allows the virus to multiply in the body.
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It is easier to take at home than drugs like Remdesivir. Treatment should be started within five days of symptom onset and taken twice daily for five consecutive days.
How does COVID-19 work again?
The team first isolated the SARS-CoV-2 BA.2 virus from a COVID-19 recovered patient and tested it to see if it developed resistance. They found that after treatment with Paxlovid, the virus remained susceptible to the drug and did not develop the associated mutations that could reduce the effectiveness of the drug.
First author Aaron F. Carlin said: “Our main concern is that the coronavirus could develop resistance to Paxlovid, so the discovery of this case was not a huge relief.
Next, the team took plasma samples from the patients to test their immunity against SARS-CoV-2. The patient’s antibodies were still effective at preventing the virus from entering and infecting new cells, suggesting that the lack of antibody-mediated immunity is also not the cause of the symptoms. patient relapse.
A return of COVID-19 symptoms after the end of Paxlovid treatment may be due to insufficient drug exposure: not enough drug reached the infected cells to stop all viral replication. . They suggest that this could be because the drug is metabolized more quickly in some people or the drug needs to be delivered over a longer treatment period.
Carlin said he hopes doctors will be able to test whether patients need longer periods of Paxlovid treatment or if they can be best treated with a combination of drugs.
Paxlovid users should be aware of the possibility of a flare-up of symptoms and be prepared to wear a mask and re-quarantine if symptoms return.
Further studies are needed to measure the frequency of recurrence, which patient populations are most susceptible, and if a return of symptoms may lead to more severe disease.
“Paxlovid’s goal is to prevent serious illness and death, and so far no one has had a relapse that requires hospitalization, so it’s still doing its job,” Smith said.
“We simply need to understand why recovery occurs in some patients and not others. More research is needed to help us adjust treatment plans as needed. “
Source: Medindia
