FDA fully approved the first monoclonal antibody to treat Covid-19 in hospitalized patients, persistent smell loss may be due to nasal cell damage, and more in this week's roundup of Covid-19 news.

• FDA on Wednesday fully approved Roche's monoclonal antibody, Actemra, to treat Covid-19 in hospitalized adult patients. The treatment was originally approved in 2010 to treat moderate to severe rheumatoid arthritis before being authorized for emergency use as a Covid-19 treatment in July 2021. "Actemra is the first FDA-approved monoclonal antibody for treating patients with severe COVID-19, providing an important option for hospitalized patients and their healthcare providers who continue to be on the frontlines treating COVID-19," said Levi Garraway, Roche's CMO. Actemra is an intravenous drug and is administered in a single, one-hour infusion. It is approved to treat hospitalized Covid-19 patients who are receiving certain steroids and need supplemental oxygen, mechanical ventilation, or extracorporeal membrane oxygenation. (Twenter, Becker's Hospital Review, 12/21; Weixel, The Hill, 12/21)

• According to new research published in Neuroimmunology Reports, a combination of two existing medications could help reduce or even potentially eliminate brain fog among long Covid patients. For the study, researchers from Yale University tested a combination of guanfacine and N-acetylcysteine in 12 patients with long Covid. Of these patients, eight reported that their brain fog symptoms went away after treatment. According to the researchers, larger, placebo-controlled clinical trials are still needed to determine the drugs' true benefits, but the early data suggests that these medications, which are safe and affordable, may be a potential treatment for long Covid patients with brain fog. "There's a paucity of treatment out there for long COVID brain fog, so when I kept seeing the benefits of this treatment in patients, I felt a sense of urgency to disseminate this information," said Arman Fesharaki-Zadeh, an assistant professor of psychiatry and neurology at Yale and one of the study's authors. (Bean, Becker's Hospital Review, 12/21)

• A persistent loss of smell, or anosmia, among Covid-19 survivors may be due to inflammatory damage to nasal cells, according to a small new study published in Science Translational Medicine. For the study, researchers from Duke University, Harvard University, and the University of California-San Diego (UCSD), analyzed olfactory epithelial tissues, which contain smell cells, from 24 biopsies. Of these samples, nine were taken from long Covid patients who continued to suffer from a loss of smell. The researchers found the patients had fewer olfactory nerve cells and that cells responsible for smell were experiencing a continuous immune response. According to Carol Yan, an otolaryngologist and head and neck surgeon at UCSD and one of the study's authors, the findings suggest that persistent smell loss may be partially due to inflammation in the nose. One potential treatment for the smell loss is platelet-rich plasma (PRP). "What we found in the clinical trial is actually PRP has a greater likelihood of improving outcomes for covid 19-related smell loss compared to placebo," Yan said. However, she noted that PRP is not a "magic bullet" and more research is needed before it can be used for patients. (Ables, Washington Post, 12/22)

• Individuals who received an updated bivalent booster were better protected against severe Covid-19 outcomes compared to those who did not, according to two new CDC reports. In one report, researchers found that updated boosters reduced the risk of hospitalization from Covid-19 by 57% compared to being unvaccinated and 45% compared to those who had only received the original monovalent vaccines. The updated boosters were especially effective among adults ages 65 and older, who are at the highest risk of severe Covid-19 symptoms. In the second study, which focused largely on adults ages 65 and older, researchers found the bivalent booster was 84% effective at preventing hospitalizations compared to those who were unvaccinated and 74% effective compared to people who had only received two doses of a Covid-19 vaccine. "These early findings show that a bivalent booster dose provided strong protection against COVID-19–associated hospitalization in older adults and additional protection among persons with previous monovalent-only mRNA vaccination," the researchers wrote. "All eligible persons, especially adults aged ≥65 years, should receive a bivalent booster dose to maximize protection against COVID-19 hospitalization this winter season." However, booster uptake, even among older adults, remains relatively low. So far, only 14% of people ages five and older and 36% of people ages 65 and older have received an updated booster. Currently, health officials are encouraging people to get their boosters as soon as possible as respiratory viruses continue to surge across the country and more people travel for the holidays. (Weixel, The Hill, 12/16; Ahn, NPR, 12/18; Sun, Washington Post, 12/16; Mueller, New York Times, 12/16)

• Wearing a surgical mask over an N95 mask is not recommended since it may lead to leakage, according to a new study published in Infection Control & Hospital Epidemiology. For the study, researchers from Mayo Clinic Phoenix and the University of Tulsa observed 100 participants who completed quantitative fit testing while wearing a 3M 1870+ filtering facepiece respirator (FFR). However, when a surgical mask was worn over the N95 mask, 13% of participants then failed the fit testing. "The additional resistance created by an overlying face mask can lead to increased airway pressures that cause leakage at the N95 FFR facial seal," the researchers wrote. (Carbajal, Becker's Hospital Review, 12/21)