Damage to endothelial cells may cause Covid-19's neurological symptoms, the omicron subvariant BA.2.75 has been detected in several U.S. states, and more in this week's roundup of Covid-19 news.

• Funding for the U.S. Agency for International Development's (USAID) global Covid-19 response will run out within the next few weeks unless Congress approves new funds, according to USAID Assistant Administrator for Global Health Atul Gawande. "We are grinding our operations to a halt," Gawande said. "The COVID task force will have to go away in the next couple of months." Since the beginning of the pandemic, USAID has helped more than 120 countries combat the coronavirus by delivering rapid tests and vaccines. "We've gotten through three of the four quarters in this football game, and we can't give up the game now on COVID," Gawande said. "We still have surges that will come." (Neukam, The Hill, 7/19)

• The Biden administration is considering expanding the eligibility for second Covid-19 boosters to all adults, instead of just those 50 and over, to combat a growing number of new infections and hospitalizations, the Washington Post reports. Currently, the United States is reporting an average of more than 100,000 new daily infections, although experts say the true number of cases is likely much higher since at-home tests often go unreported. Covid-19 hospitalizations and deaths are also on the rise, but they are still far below the levels seen in January. As of now, the plan to expand booster eligibility is still in its early stages and will need both FDA and CDC sign-off. However, some health experts have expressed skepticism about the necessity of a second booster dose for younger adults. "I do think [a second booster shot] does make sense for certain groups, but a universal boosting strategy doesn't make sense," said Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia and an outside advisor to FDA. "At some level, we're going to have to get used to mild illness and moderate illness as part of this virus — which is going to be with us for the rest of my life, the rest of my children's lives, the rest of their children's lives." (Diamond et al., Washington Post, 7/11; Stein, "Shots," NPR, 7/19; LaFraniere, New York Times, 7/11)

• Antibodies that damage endothelial cells lining the brain's blood vessels may cause the inflammation and neurologic damage experienced by Covid-19 patients, according to a new study published in Brain. Previously, researchers at the National Institute of Neurological Disorders and Stroke (NINDS) had found blood vessel damage and inflammation in the brains of deceased Covid-19 patients. To determine a potential cause of this damage, the researchers examined brain tissue from nine Covid-19 patients who had microvascular abnormalities on post-mortem MRI and compared them with 10 controls. They examined tissue from seven male patients and two female patients, ranging in age from 24 to 73 years. Overall, the researchers found that the blood vessel damage and inflammation was accompanied by extensive endothelial cell activation. "Deposition of complement cascade and immunoglobulins suggests an immune-mediated injury to the endothelial cells," the researchers wrote. "The inflammatory process results in microglia activation causing neuronal injury and neuronophagia."According to the researchers, these findings may help scientists understand how to treat long-term neurological symptoms in Covid-19 patients. (George, MedPage Today, 7/11)

• BA.2.75, the latest omicron subvariant to be identified, has been reported in seven U.S. states, including California, Illinois, and New York. Globally, 201 cases have been identified in more than a dozen countries, according to data from outbreak.info. BA.2.75 has several mutations that make it more transmissible and adept at evading immunity than BA.5, the subvariant that is currently dominant in the United States. So far, it is unclear whether BA.2.75 causes more severe illness or whether it will eventually outcompete BA.5 to become the dominant variant. "It spread to many different countries already, so we know that it has some sort of staying power," said Shishi Luo, associate director of bioinformatics and infectious disease for Helix Labs. According to Luo, because of BA.2.75's increased immune evasion, "we sort of know ahead of time that this one will cause some trouble." (Bean, Becker's Hospital Review, 7/20; Goodman, CNN, 7/18)

• Covid-19 patients are at a heightened risk of developing diabetes and heart disease in the first few weeks after infection, according to a new study published in PLOS Medicine. For the study, researchers analyzed EHR records from patients in the United Kingdom. They matched 428,650 Covid-19 patients with controls who did not have Covid-19 to compare the risks of new heart disease and diabetes diagnoses in the year post-infection. Overall, there was a six-fold increase in heart disease diagnoses, primarily due to an 11-fold increase in pulmonary embolism and a six-fold increase in atrial arrhythmias. This risk was particularly elevated during the first few weeks after infection before beginning to decline after five weeks and returning to baseline or lower levels within 12 weeks to a year. In addition, Covid-19 patients had an 80% higher chance of being diagnosed with diabetes in the first month after infection. This risk for diabetes remained elevated by 27% for up to 12 weeks. "It's definitely reassuring that over the longer timeframe, cardiovascular disease and diabetes risk does seem to return to baseline levels," said Emma Rezel-Potts, an epidemiologist at King's College London and one of the study's authors. "But we do have to be cautious in the acute period with cardiovascular disease and take note that the risk of diabetes seems to be elevated for several months, so that could be a good opportunity for risk prevention." (Carbajal, Becker's Hospital Review, 7/20)