It is an amazing ad. Joe Biden tested positive for Covid-19 again on Saturday and Sunday. However, the president of the United States tested negative a few days earlier, and this for four days, after the July 21 contamination. in a tweetannounced return to solitary confinement.
In a letter released by the White House, the president’s doctor, Kevin O’Connor, speaks of a “rebound” in the positivity of Covid-19. “It has not been recontaminated, it is a rebound of its own virus,” Bruno Megarbane, head of the intensive care unit at the Lariboisière hospital in Paris, confirms to BFMTV.
The antiviral treatment in question
“Rebound positivity is seen in a small percentage of patients treated with Paxlovid,” writes Kevin O’Connor. Joe Biden was actually taking this antiviral treatment – little used in France – which works by reducing the virus’s ability to replicate and prevents serious forms of the disease.
Paxlovid “allowed for the duration of the treatment to block the replication of the virus”, explains Bruno Megarbane. However, when the treatment was stopped, the virus multiplied again, which explains the return of positive tests for Joe Biden.
“It is possible that during the period in which Paxlovid was effective, his immune system was not well stressed to mount a sufficient neutralization response for him to recover definitively”, continues the professor.
In fact, it was this treatment that temporarily caused the president’s tests to turn negative. “We artificially broke the viral load,” Benjamin Davido, an infectious disease specialist at the Raymond-Poincaré hospital in Garches (Hauts-de-Seine), tells BFMTV.com.
“Joe Biden was tested because he is president of the United States”
According to a recently published study in the United States, about 2% of patients treated with Paxlovid experience such a rebound. However, this is a figure that should be taken with a grain of salt. “Joe Biden took the test because he is president of the United States, Benjamín Davido abounds. Otherwise, we no longer do control PCR tests until now after infection.”
With this low probability of retesting, it’s hard to know how many people are negative and then positive again, especially since, like Joe Biden, they are asymptomatic.
A “viral persistence” instead of a “rebound”
However, this situation does not mean that it is the antiviral treatment that causes this rebound. On the contrary, he made Joe Biden a “false negative” for a few days. However, without taking Paxlovid, the duration of positivity would not have been shorter for the president.
“We artificially broke the viral load but the natural evolution of the virus would have been the same because there is viral persistence,” explains Benjamín Davido.
In fact, the infectologist prefers to speak of “viral persistence” rather than rebound. “Without the antiviral treatment, I certainly wouldn’t have had this moment of negativity, but today I would have tested positive again,” he continues. If it reduces the risk of developing a severe form, Paxlovid does not necessarily reduce the duration of positivity and therefore the possibility of contagion.
A longer drop in viral load
Thus, Joe Biden is experiencing the viral persistence of Covid-19. Beyond the problem of antiviral treatments, it is the duration of the disease that is raised here. “We never really knew how to answer the question,” says Benjamín Davido.
After infection with the virus, the time to positivity is “extremely variable.” “It can last more than a month in some patients depending on the history,” explains the infectologist.
For example, several studies have found that people over the age of 60 have a longer decline in viral load and therefore may test positive longer. This is the case of Joe Biden, 79 years old. In addition, the variants of the Covid-19 that are currently circulating are “longer and with a particularly high viral load”, details Benjamín Davido.
Finally, there is also the issue of contagiousness of patients. It is possible that these people will become contagious again, hence the isolation of Joe Biden. On the other hand, a positive test can also be the result of traces of the virus, leading to a much lower risk of contagion. “However, if there are still symptoms, it is likely that the patient is still contagious,” concludes Benjamín Davido.
Source: BFM TV
