FDA authorizes a new at-home rapid Covid-19 test, a study finds that mental health-related ED visits increase after Covid-19 surges, and more in this week's roundup of Covid-19 news.

• Moderna on Wednesday released interim data from two clinical trials of its Covid-19 vaccine in children between six months and six years of age. In total, the trials included 2,500 children ages six months to 23 months and 4,200 children ages two to six, who were given two 25 microgram doses of the vaccine 28 days apart. Overall, the vaccine had a 43.7% efficacy rate against coronavirus infection among children six months to 23 months and a 37.5% efficacy rate among children ages two to six. Although the reported efficacy was lower than what was seen in previous vaccine trials in adults, Moderna said the efficacy was on par with what would be expected of a two-dose vaccine series in adults against the omicron variant, which is known to evade vaccine immunity. No cases of severe illness, hospitalizations, or deaths were reported, so the company could not estimate efficacy rates against those outcomes. Overall, the company said the pediatric doses "showed a robust neutralizing antibody response" similar to adult doses and had "a favorable safety profile," with side effects being largely mild or moderate. According to STAT News, Moderna plans to ask FDA, as well as regulators in other countries, to authorize its vaccine for children under 6 in the coming weeks. "Given the need for a vaccine against COVID-19 in infants and young children we are working with the U.S. FDA and regulators globally to submit [this] data as soon as possible," said Moderna CEO Stéphane Bancel. (AP/Modern Healthcare, 3/23; Branswell/Herper, STAT News, 3/23; Archie, NPR, 3/23; Foley, Politico, 3/23)

• Prevalence of the omicron subvariant BA.2, which has contributed to a rise in Covid-19 cases across Europe, is steadily growing in the United States. According to new CDC data, the omicron subvariant BA.2 made up 34.9% of all circulating coronavirus variants in the United States for the week ending March 19. In comparison, data from Walgreens, which conducts testing nationwide at its pharmacies, showed that BA.2 made up 51% of all positive Covid-19 cases at the end of the same week. However, despite the subvariant's growth in the United States, leading public health officials have said they are not expecting another dramatic surge in cases, largely due to increased population immunity through vaccination and infection during the omicron surge. "The bottom line is we'll likely see an uptick in cases, as we've seen in the European countries, particularly the U.K.," said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. "Hopefully we won't see a surge—I don't think we will." (Garfinkel, Axios, 3/22; Kimball, CNBC, 3/23)

• FDA last week announced several moves regarding Covid-19 rapid tests. On March 16, the agency authorized Phase Scientific International's INDICAID Covid-19 Rapid Antigen At-Home Test for emergency use. The test is authorized for self-use by individuals ages 14 or older, as well as parental use in children ages two and older, and returns results in 20 minutes. Meanwhile, FDA also announced four class 1 recalls, the most serious type of recall, for four Covid-19 rapid tests from Celltrion USA, SD Biosensor, E25Bio, and LuSys Laboratories. Celltrion USA's tests were recalled for high numbers of false positive reports, while both SD Biosensor's and E25Bio's tests were recalled due to lack of authorization for U.S. marketing or distribution. LuSys Laboratories' tests were recalled due to a failure to provide appropriate validation data, as well as a lack of emergency use authorization. (AHA News, 3/21; Gleeson, Becker's Hospital Review, 3/18)

• Pfizer on Tuesday announced that it has reached a deal with UNICEF to provide around 4 million courses of Paxlovid, its antiviral Covid-19 treatment, for use in 95 low- and middle-income countries, including Afghanistan, Pakistan, and Zimbabwe. According to the company, shipments of the treatment will begin in April and continue throughout 2022. "Supplying to UNICEF is an important part of our comprehensive strategy to accelerate access to Paxlovid to treat Covid-19 infection as quickly as possible and at an affordable price in order to decrease the strain on health care systems and help save lives in low- and middle-income countries," said Pfizer CEO Albert Bourla. Previously, Pfizer agreed to license Paxlovid to the United Nations-backed Medicines Patent Pool, which would allow other drugmakers to make generic versions of the antiviral pill to supply poorer countries. Overall, 35 companies based in 12 countries—including Teva Pharmaceutical Industries, Sun Pharmaceutical Industries, and Viatris—will produce generic versions of the treatment. (Choi, The Hill, 3/22; Walker, Wall Street Journal, 3/22; Erman, Reuters, 3/17)

• Mental health-related ED visits increased after Covid-19 surges according to a new study published in JAMA Psychiatry. For the study, researchers used data from the National Syndromic Surveillance Program to analyze a sample of U.S. adults between the ages of 18 and 64 with several million ED visits at 3,600 hospitals nationwide related to 10 mental health disorders between Jan. 1, 2019, and Aug. 14, 2021. Across the overall population, mental health-related ED visits after a Covid-19 surge were relatively stable, with only a 1.5% increase after a surge. However, different racial groups saw significant increases in rates of ED visits for different disorders following a surge. In particular, Black patients saw a 14% increase in trauma- and stress-related disorder visits after a surge compared with during a surge. Similarly, Latino patients saw a 24.3% increase in visits for bipolar disorders, and white patients had an 11.5% increase in visits for schizophrenia spectrum disorder. American Indian or Alaska Native patients also saw increases for depressive disorder (9.9%), bipolar disorder (40%), and stress-related disorders (42.4%). Among Asian patients, they had a 26.6% increase in visits for depressive disorders, but a 31.6% decrease in visits for schizophrenia spectrum disorders. According to the study, these increases in mental health-related ED visits were likely due to stress and increased mental health issues during the pandemic, with marginalized communities in particular experiencing disproportionate effects. (Devereaux, Modern Healthcare, 3/16)