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August 19, 2022

Covid-19 roundup: Could a longer course of Paxlovid prevent viral rebound?

Daily Briefing

    The United Kingdom becomes the first country to authorize a booster targeting the omicron variant, Covid-19 patients may experience hair loss after infection, and more in this week's roundup of Covid-19 news.

    • The national Covid-19 public health emergency (PHE) is likely to be extended into January 2023, Politico reports. Currently, the PHE is set to end on Oct. 13, and HHS said it would give states and health providers 60 days' notice, which has not yet been given, before ending it. "Silence from the administration means that the public health emergency will almost certainly be extended into January 2023," said Larry Levitt, EVP for health policy at the Kaiser Family Foundation. In addition, Chip Kahn, CEO of the Federation of American Hospitals, said that now is not the right time to end the PHE since Covid-19 is still significantly impacting the health care system. "Even though the public has turned the page, we have to deal with it every day," he said. "The flu is coming, as well as the possibility of Covid spread that would lead to more hospitalizations. We're just not ready to make a big shift." So far, the PHE has been extended every 90 days since it was first issued in January 2020. (Lim, Politico, 8/17; Bettelheim, Axios, 8/16)
    • The United Kingdom on Monday authorized a bivalent Covid-19 booster targeting the omicron variant, making it the first country to do so. The booster, which was developed by Moderna, is designed to target the original strain of the coronavirus, as well as the original omicron variant, BA.1. "What this bivalent vaccine gives us is a sharpened tool in our armoury to help protect us against this disease as the virus continues to evolve," said June Raine, the head of the U.K.'s Medicines and Healthcare Products Regulatory Agency. According to Moderna CEO Stéphane Bancel, the authorization highlights "the dedication and leadership of the U.K. public health authorities in helping to end the Covid-19 pandemic." He also noted that the booster has "an important role to play in protecting people in the U.K. from Covid-19 as we enter the winter months." In comparison, health officials in the United States have asked vaccine manufacturers to develop boosters targeting omicron subvariants BA.4 and BA.5 instead. These two subvariants currently make up the majority of Covid-19 cases in the United States, and bivalent vaccines targeting BA.1 are not as effective against them. (Sullivan, NPR, 8/16; Gross, New York Times, 8/15; Roland, Wall Street Journal, 8/15; Doherty, Axios, 8/15)
    • As the next generation of Covid-19 boosters is being prepared for the fall, FDA is planning to take a controversial approach to evaluating their safety and efficacy, NPR reports. Instead of authorizing the new vaccines based on studies in humans, FDA will base its decision on studies involving mice, as well as human neutralizing antibody data from previous studies looking at bivalent BA.1 boosters. So far, some health experts have pushed back against the approach, saying that mice data cannot reliably be generalized to humans. "For the FDA to rely on mouse data is just bizarre, in my opinion," said John Moore, an immunologist at Weill Cornell Medicine. "Mouse data are not going to be predictive in any way of what you would see in humans." However, other experts argue that the United States does not have enough time to wait for human studies, which will likely not be available until late October or early November, to authorize new boosters. They also said that the country has had enough experience with Covid-19 vaccines to understand how safe they are and can treat them like flu vaccines, which are changed every year to match circulating strains but not routinely tested. "We're going to use all of these data that we've learned through not only from this vaccine but decades of viral immunology to say: 'The way to be nimble is that we're going to do those animal studies," said Deepta Bhattacharya, an immunobiologist at the University of Arizona College of Medicine. "We're really not going out too far on a limb here." Currently, Pfizer-BioNTech and Moderna are expected to submit their booster data to FDA by the end of the month, and the agency hopes that millions of new doses will be available in September. (Stein, "Shots," NPR, 8/18)
    • Some health experts are questioning whether Paxlovid courses should be extended to prevent potential viral rebound, TIME reports. According to data submitted to FDA, Pfizer found that rebound occurs in roughly 1% to 2% of patients taking Paxlovid. However, David Ho, a professor of medicine and director of the Aaron Diamond AIDS Research Center at Columbia University, said he believes the prevalence of viral rebound with Paxlovid is likely much higher. "The virus is rather persistent," Ho said. "And we believe that five days of treatment is not enough to have that form decay so that it's nonexistent at the end of those five days." Currently, Ho and his team are studying Paxlovid, and early results suggest that extending a Paxlovid course from five days to seven to 10 days could reduce the risk of rebound by tenfold. According to Ho, additional days of treatment could eliminate more intermediary forms of the virus in the body, but more research is needed to validate this idea. In a statement, a spokesperson from Pfizer said the company is working with FDA to set up a trial to study Paxlovid rebound further. (Park, TIME, 8/11; Twenter, Becker's Hospital Review, 8/15)
    • According to some studies, some Covid-19 patients may have an increased risk of hair loss following their illness. For example, a recent study published in Nature Medicine found that patients who previously had Covid-19 were almost four times more likely to suffer from hair loss than those who had never been infected. Similarly, another study in the Lancet found that roughly 22% of hospitalized Covid-19 patients experienced hair loss. Many clinicians have also said they have seen more patients reporting hair loss. "A day doesn't go by that I don't get asked about it," said Brian Abittan, director of skin and hair rejuvenation at Mount Sinai Health System. The most common type of hair loss experienced by post-Covid patients is telogen effluvium, which occurs when the hair's growth cycle is disrupted, often because of trauma or stressful life events. According to Alexis Young, a dermatologist at Hackensack University Medical Center, patients could start shedding hair as soon as two or three months after infection, and the shedding could last up to six months. However, because this type of hair shedding is not a scarring process, the hair can and likely will grow back on its own, although it typically takes around a year and a half to do so."The majority of people do, ultimately, grow their hair back," Abittan said. "It just takes time." (D'Ambrosio, MedPage Today, 8/12)

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