FDA has authorized updated Covid-19 boosters for children as young as six months, a study finds monoclonal antibodies are no longer effective against some of the newer omicron subvariants, and more in this week's roundup of Covid-19 news.

• Amid rising cases and hospitalizations across the country, the Biden administration on Thursday announced a new "winter preparedness plan" against Covid-19. Over the last two weeks, Covid-19 cases have increased by roughly 55%, and hospitalizations have grown by over 20%. Covid-19 deaths have also jumped 65% during the same time period. Under the plan, the administration plans to collaborate with communities on mobile vaccination sites, provide more support to nursing homes, and long-term care facilities, and pre-positioning critical supplies (masks, gloves, gowns) from the Strategic National Stockpile. The administration is also restarting its program providing free Covid-19 tests to American households by mail. The program was initially paused in September after sending out over 600 million tests. Households can now order four at-home tests from COVIDTests.gov and have them mailed to their house for free, regardless of home many tests they ordered previously. According to an administration official, the tests are expected to ship out the week of Dec. 19. (Weintraub, USA Today, 12/15; Weiland, New York Times, 12/15; Weixel, The Hill, 12/15)

• FDA last week authorized updated Covid-19 boosters from both Pfizer-BioNTech and Moderna for children as young as six months. Under the authorization, children ages six months to five years can receive a Moderna booster if they have already received two shots of the company's original vaccine, and children ages six months to four years who have received two doses of Pfizer-BioNTech's original vaccine can get the updated booster as a third dose. However, children who have already received three doses of Pfizer-BioNTech's are currently not eligible for an updated booster since FDA is still evaluating data for this group. "Parents and caregivers can be assured that the FDA has taken a great deal of care in our review, and we encourage parents of children of any age who are eligible for primary vaccination or a bivalent COVID-19 vaccine booster dose to consider seeking vaccination now as it can potentially help protect them from COVID-19 during a time when cases are increasing," said Peter Marks, director of the FDA's Center for Biologics Evaluation and Research. In a statement, FDA Commissioner Robert Califf said it was important to get young children vaccinated before the holidays "where more time will be spent indoors." (Gonzalez, Axios, 12/8; AP/Modern Healthcare, 12/8)

• According to a new study published in the New England Journal of Medicine, the omicron subvariants BQ.1.1 and XBB were able to evade several monoclonal antibodies, but not antiviral drugs. For the study, researchers from the University of Tokyo used a live-virus neutralization assay to test how well different monoclonal antibodies and antivirals performed against BQ.1.1 and XBB viruses isolated from infected patients. Overall, none of the monoclonal antibodies tested, including bebtelovimab and Evusheld, were effective against BQ.1.1 or XBB. In comparison, antivirals, including remdesivir, molnupiravir, and Paxlovid, maintained their efficacy against B.Q.1.1 and XBB. Because of the lack of efficacy against newer coronavirus variants, FDA has rescinded authorization for most monoclonal antibodies aside from Evusheld. However, the agency has also warned of Evusheld's limited effectiveness against newer variants. According to the study's authors, "[t]he continued evolution of omicron variants reinforces the need for new therapeutic monoclonal antibodies for Covid-19." (Beusekom, CIDRAP News, 12/8)

• Pfizer has signed a deal with a Chinese-based pharmaceutical company, China Meheco Group, to sell its antiviral Paxlovid in the country. Currently, China is facing a surge of Covid-19 cases as it attempts to ease its "zero Covid" policy. The country initially approved Paxlovid in February, and the treatment was made available for high-risk patients in hospitals. The new deal allows for Chinese citizens to have broader access to the treatment through retail sales, which could also lead to a significant increase in earnings for Pfizer. According to a Chinese health care platform, Paxlovid sold out in just over half an hour after its listing was first reported in the media, highlighting surging demand for Covid-19 and flu medications in the country. In a statement, Pfizer said that it is "actively collaborating with all stakeholders to secure an adequate supply of Paxlovid in China and remains committed to fulfilling the COVID-19 treatment needs of patients in China." (Schonfeld, The Hill, 12/14; Reuters, 12/14)

• Increased stress from the pandemic appears to have physically changed and prematurely aged the brains of teenagers by at least three to four years, according to a new study published in Biological Psychiatry: Global Open Science. For the study, researchers from Stanford University evaluated brain assessments from 81 adolescents from before the pandemic and compared to 82 young adults who have lived through the pandemic. Overall, the researchers found that the brains from pandemic youth were more physically aged compared to those of their sex- and age-matched peers from before the pandemic. According to the researchers, these changes were similar to the brains of people who had experienced high levels of adversity during childhood and suggests that these individuals' developmental process sped up during the pandemic. The team also assess mental health, anxiety, and depression symptoms among the participants and found that the pandemic group was more likely to report severe symptoms of anxiety, depression, and internalizing problems. So far, it is unclear whether these brain changes are permanent. "Will their chronological age eventually catch up to their 'brain age'?" said Ian Gotlib, a psychology professor at Stanford and the study's lead author. "If their brain remains permanently older than their chronological age, it's unclear what the outcomes will be in the future." (Hou, "Changing America," The Hill, 12/1; Moreno, Axios, 12/2; Lewis, Washington Post, 12/1)