Researchers are now testing a Covid-19 vaccine patch for long-term protection against the coronavirus, Pfizer says its Covid-19 antiviral drug appears to be effective against omicron, and more in this week's roundup of Covid-19 news.

• Researchers at Yale University have developed a clip-on device that can detect low levels of the coronavirus in the air and alert people of potential viral exposure, USA Today reports. The device, called the Fresh Air Clip, is a small 3D-printed badge that collects samples of air on a film. Between January and May 2021, researchers had 62 participants wear the clips at work for five days before testing the films inside the clips for the coronavirus. Overall, the researchers found evidence of the coronavirus in five clips and detected levels of the virus below the amount needed to be infectious. Currently, the researchers are testing the Fresh Air Clips in additional studies at health care facilities. "We are keen to expand use of the Fresh Air Clip and are exploring how best to scale application in workplaces, schools and with community members," said Krystal Godri Pollitt, an assistant professor of epidemiology at the Yale School of Public Health and the clip's creator. "We are currently using the Fresh Air Clip to monitor airborne viral exposures in high-risk settings and have risk of SARS-CoV-2 transmission but also common respiratory virus[es], such as influenza and rhinovirus." (Snider, USA Today, 1/20)

• According to new data from the U.K. Health Security Agency, protection against infection offered by a booster dose of Pfizer-BioNTech's Covid-19 vaccine is likely short-term, lasting less than six months. Although researchers found that protection against symptomatic infection was relatively high—at 70%—two weeks after a booster dose, the protection dipped to around 50% by three months. Researchers estimate that the level of protection will continue to decline going forward, dropping to around 40% after four months. However, researchers also found the boosters offered robust protection against severe disease, beginning at around 95% and remaining around 80% even after four months. Currently, there is only short-term data available for Moderna's vaccine, but its results are likely to be similar to Pfizer-BioNTech's numbers given their similar technologies and comparable performance against the delta variant, NPR reports. (Doucleff, "Goats and Soda," NPR, 1/19)

• Researchers are now testing Emergex Vaccine Holdings' new Covid-19 vaccine patch in hopes that it will provide long-lasting protection against the coronavirus, The Hill reports. The vaccine, which is called PepGNP-Covid19, works by applying a patch with microneedles to a person and then taking it off. Instead of generating an antibody response, the vaccine patch stimulates cellular immunity in T cells that could target the coronavirus and eliminate it. In the study, researchers will test two vaccine patches of slightly different strengths, on 26 participants who will be followed for six months. "With this new vaccine that generates this cellular immunity we hope to have a longer period of protection ... we don't know yet, but it could be one year, two years, three years," said Blaise Genton, who heads the study. (Lonas, The Hill, 1/19)

• The World Health Organization (WHO) last week recommended two new drugs to treat Covid-19. In a news release, WHO strongly recommended the use of baricitinib, an oral drug usually used to treat rheumatoid arthritis, for patients with severe or critical Covid-19. In addition, the organization conditionally recommended using the monoclonal antibody drug sotrovimab to treat patients with mild or moderate Covid-19 if they are at high risk of hospitalization. According to Axios, WHO's recommendations are based on evidence from seven clinical trials with over 4,000 patients who developed a wide range of Covid-19 symptoms. "The extent to which these medicines will save lives depends on how widely available and affordable they will be," WHO said, adding that it is working to "secure global supply capacity and equitable and sustainable access to the newly recommended therapeutics." (Chen, Axios, 1/15)

• A study published in Alzheimer's & Dementia found that hospitalized Covid-19 patients who had no prior history of dementia had elevated levels of brain injury biomarkers. For the study, researchers analyzed data from 251 hospitalized Covid-19 patients without a history of dementia, assessing them on seven serum markers for neurodegeneration. All patients in the study were hospitalized in New York City from March to May 2020. The researchers found that four serum markers were significantly elevated in Covid-19 patients with encephalopathy and those who died in the hospital, and that the remaining three were as high or higher in the Covid-19 patients as they were among Alzheimer's patients who had never had Covid-19. These findings suggest "a profound neurological insult in these patients," according to the researchers. "Traumatic brain injury, which is also associated with increases in these biomarkers, does not mean that a patient will develop Alzheimer's or related dementia later on, but does increase the risk of it," said Thomas Wisniewski, a researcher at the New York University Grossman School of Medicine. "Whether that kind of relationship exists in those who survive severe Covid-19 is a question we urgently need to answer with ongoing monitoring of these patients." (George, MedPage Today, 1/14)

• Pfizer on Tuesday announced that its oral Covid-19 drug Paxlovid appears to be effective against the omicron variant. According to the company, three separate lab studies showed nirmatrelvir, the drug's main protease inhibitor, can prevent omicron from replicating. "These data suggest that our oral Covid-19 therapy can be an important and effective tool in our continued battle against this devastating virus and current variants of concern, including the highly transmissible omicron," said Mikael Dolsten, Pfizer's chief scientific officer. "We will continue to monitor the treatment’s activity in real-world settings and believe that these in vitro findings will continue to be validated." FDA last month authorized Paxlovid's use for patients at high risk of severe Covid-19, but current supply remains limited. Fewer than 200,000 courses of the treatment have been distributed in the United States so far. (Weixel, The Hill, 1/18; Hopkins, Wall Street Journal, 1/18)