The Biden administration will purchase an additional 1.5 million doses of Novavax's COVID-19 vaccine, COVID-19 infection could boost male patients' immune responses to different vaccines, and more in this week's roundup of COVID-19 news.

• A protein in the lung that attaches to the coronavirus may form a protective barrier and block infection from the virus, according to a new study published in PLOS Biology. For the study, researchers from the University of Sydney screened human cells for certain genes and examined the lungs of COVID-19 patients with CRISPR technology. The researchers found that the LRRC15 receptor protein can bind to the spike of the coronavirus and prevent the virus from infecting neighboring cells. According to Lipin Loo, a postdoctoral researcher, and Matthew Waller, a Ph.D. student, the protein "acts a bit like Velcro, molecular Velcro, in that it sticks to the spike of the virus and then pulls it away from the target cell types." Waller also noted that LRRC15 "also controls antiviral responses, as well as fibrosis, and could link COVID-19 infection with lung fibrosis that occurs during long COVID." Overall, the researchers said the study "opens up an entirely new area of immunology research" around LRRC15 and "offers a promising pathway to develop new drugs to prevent viral infection from coronaviruses like COVID-19 or deal with fibrosis in the lungs." It could also help explain why some people may develop severe COVID-19 infections while others never get sick even after exposure. (Falconer, Axios, 2/10)

• Growing evidence supports a link between COVID-19 infection and new-onset diabetes, according to a new study published in JAMA Network Open. However, vaccination may largely reduce the risk of diabetes post-infection. For the study, researchers from Cedars-Sinai Health System analyzed data from 23,709 adult patients who were treated for at least one COVID-19 infection at the health system between the start of the pandemic and June 2022. Of the participants, 14,856 were unvaccinated before infection, and 8,853 were vaccinated. Overall, the researchers found that COVID-19 infection was associated with a 58% increased risk of developing new-onset diabetes compared to another benchmark condition. However, this increased risk was mostly found in unvaccinated patients, who had a 78% increased chance. In comparison, there was no significant association between vaccinated patients and new-onset diabetes. In total, 2.7% of the unvaccinated group developed diabetes post-infection compared to 1% of the vaccinated group. "Our results validate early findings revealing a risk of developing type 2 diabetes after a COVID-19 infection and indicate that this risk has, unfortunately, persisted through the Omicron era," said Alan Kwan, the study's lead author. "These results suggest that COVID-19 vaccination prior to infection may provide a protective effect against diabetes risk." (Monaco, MedPage Today, 2/14)

• The Biden administration is planning to buy an additional 1.5 million doses of Novavax's protein-based COVID-19 vaccine, adding to its initial order of 3.2 million doses from July 2022. "This agreement acknowledges the need to offer the American people a diverse COVID-19 vaccine portfolio and underscores the importance of Novavax' partnership with the U.S. government to ensure continuous access to a protein-based option as part of public health measures," said Novavax president and CEO John Jacobs. So far, around 77,500 doses of Novavax's vaccine have been administered out of more than 1 million available doses. According to The Hill, the initial doses purchased by the government are set to expire near the end of the month. "[The U.S. government] and Novavax have worked within our existing contract to secure additional vaccine doses – providing continued optionality for the American people," said an HHS spokesperson. (Choi, The Hill, 2/13)

• A prior COVID-19 infection may boost immune response to a future flu vaccine, according to a new study published in Nature — but only for men. For the study, researchers from Yale University compared blood samples from 33 patients who had had mild COVID-19 and 40 age- and sex-matched controls who had not been infected. Later, all participants received a seasonal flu vaccine, and their blood samples were collected again at different points in time, including up to 100 days post-vaccination. Overall, the researchers found that male patients who had recovered from COVID-19 had stronger inflammatory responses and more effective-memory T cells than female patients who had recovered from COVID-19, as well as healthy controls. "You see significantly stronger inflammatory responses in the Covid-recovered males," said John Tsang, a systems immunologist at Yale and one of the study's authors. "That was a huge surprise. Often, you find that kind of response to be higher in females." According to the researchers, they hope that these findings can help improve vaccines or potentially predict how a person might respond to an infection. (Chen, Wired, 2/10)

• The potential association between long COVID and functional neurological disorder (FND), or abnormalities in brain signaling without significant structural damage to the brain itself, remains understudied, according to a new systemic review published in the European Journal of Neurology. This means that people with FND may be inappropriately diagnosed with long COVID, affecting their overall treatment and prognosis. For the review, researchers analyzed 102 studies on long COVID that included 412,726 patients. Among these studies, 31 specifically recruited long COVID patients while the others examined individuals with acute COVID-19 who were screened for long COVID symptoms. Overall, the researchers found that none of the studies systematically looked for positive features of FND, and there was not sufficient evidence to either support or refute an FND diagnosis based on the data collected. "Our systematic review shows that the possibility that some people labeled as having long COVID might in fact be experiencing a form of functional neurological disorder has, so far, been largely overlooked in the medical literature," said Tiago Teodoro, one of the review's authors from St. George's Hospital in London. "This is a major problem for understanding long COVID but primarily for patient management, as this is a condition with specific diagnostic criteria and for which effective treatments are available." (George, MedPage Today, 2/14)