FDA authorizes the first Covid-19 test to identify and differentiate between different coronavirus variants, the United States begins its rollout of vaccines for children under five, and more in this week's roundup of Covid-19 news.

• Moderna this week said it hopes to have its updated Covid-19 booster shot available for public distribution by August. "We've been producing millions of doses over the last couple months," said Moderna president Stephen Hoge. "We would hope to have tens of millions to hundreds of millions of doses available in August, September, and October to support boosting prior to the fall respiratory season." In a clinical trial of 800 participants, researchers found that Moderna's updated booster, which is called mRNA-1273.214 and designed to target both the original coronavirus and the omicron variant, resulted in a 5.4-fold increase in neutralizing antibodies among all participants and a 6.3-fold increase among those who were not previously infected. Although the levels of neutralizing antibodies against the newer omicron subvariants were lower than those against the original omicron variant, they were still high overall, Moderna said. "In the face of SARS-CoV-2's continued evolution, we are very encouraged that mRNA-1273.214, our lead booster candidate for the fall, has shown high neutralizing titers against the BA.4 and BA.5 subvariants, which represent an emergent threat to global public health," said Moderna CEO Stéphane Bancel. (Loftus, Wall Street Journal, 6/22; Reuters, 6/22; Twenter, Becker's Hospital Review, 6/22; Cerullo, CBS News, 6/23)

• Almost 20% of adults who had Covid-19 now have symptoms of long Covid, according to a new "Household Pulse Survey" from the Census Bureau and the National Center for Health Statistics. More than 62,000 adults answered the survey, and 40% said they previously had Covid-19. Of this group, 19% said they are still experiencing symptoms three months or longer after their initial infections, and 14% said they had had lingering symptoms at some point. In addition, the survey found that women reported higher rates of long Covid than men at 9.4% and 5.5%, respectively. Rates of long Covid were also found to vary across different states. Kentucky, Alabama, and Tennessee were the states with the highest rates, while Hawaii, Maryland, and Virginia had the lowest rates of long Covid. So far, the prevalence of long Covid remains unclear, with estimates ranging from a small minority to a majority of Covid-19 survivors. (Choi, The Hill, 6/22)

• Last week, FDA and CDC officially authorized Covid-19 vaccines for children as young as six months. The United States has now begun its vaccination campaign for children under five, which President Joe Biden called a "monumental step forward" in the country's pandemic response. "It marks an important moment in the pandemic because it was the last group, the last demographic, that had not had the opportunity to keep themselves maximally safe," said Bob Wachter, the chair of medicine at the University of California, San Francisco. "It's not likely to turn the tide in terms of where we are generally in the pandemic, but for the parents of those kids, it’s an important watershed." Although some parents have been eager to vaccinate their young children, only 18% of parents with children under five said they vaccinate their children right away after the shots were authorized, according to a recent Kaiser Family Foundation poll. In comparison, more than a third said they would wait and see before vaccinating their children, and 27% said they would "definitely not" vaccinate their children. Although children are less likely to develop severe Covid-19, more than 40,000 have been hospitalized and over 1,000 have died from disease since the beginning of the pandemic. Health authorities recommend that all children, regardless of whether they have previously had Covid-19, be vaccinated to provide them with the most protection and reduce the risk of future infections or complications. (Cowan, New York Times, 6/21; Bernstein/Wu, Washington Post, 6/21; Goldstein, New York Times, 6/21; Simmons-Duffin, "Shots," NPR, 6/22)

• FDA last week authorized Labcorp's VirSeq SARS-CoV-2 NGS Test, which can be used to identify and differentiate between different coronavirus variants in positive respiratory samples. According to the agency, it is the first test authorized for such a purpose. Because of the test's high complexity, it must be performed at Labcorp testing locations that are certified under the Clinical Laboratory Improvement Amendments of 1988. The test is intended to be used by health care providers who believe the results could assist in determining appropriate clinical care depending on a patient's medical history and other information. (AHA News, 6/15; FDA news release, 6/14)

• Pfizer last week announced it will stop adding patients to a phase 2/3 clinical trial of Paxlovid in patients with a standard risk of severe Covid-19 after data showed that the treatment did not significantly reduce the risk of hospitalization or death. In the trial, standard-risk patients saw a 51% risk reduction for hospitalization and death after taking Paxlovid, which the company said was "non-significant." Walid Gellad, director of the Center for Pharmaceutical Policy and Prescribing at the University of Pittsburgh, said these findings reinforce "that Paxlovid is not going to have a big role in vaccinated people except in people who are maybe at highest risk." He added that "[m]aybe in a bigger trial, it [the 51% risk reduction] would be statistically significant, but the effect is small." According to Pfizer, it will continue testing the effects of Paxlovid in high-risk patients, and the results of the current trial will be added to its application for full FDA approval of the treatment. (Twenter, Becker's Hospital Review, 6/15; Bettelheim, Axios, 6/14; Herper/Mast, STAT News, 6/14)

• According to CDC data, the omicron subvariants BA.4 and BA.5 now account for roughly 35% of all new Covid-19 cases in the United States. Specifically, BA.5 accounted for 23.5% of cases in the week ending June 18, up from almost 15% the week before, and BA.4 accounted for 11.4% of cases, up from 8% the week before. Although the omicron subvariant BA.2.12.1 remains the dominant variant in the United States at 56%, health experts earlier this month said they expect BA.4 and BA.5 to soon outpace BA.2.12.1. So far, modeling from Mayo Clinic suggests that the daily average of Covid-19 cases will increase from 73,783.9 on June 19 to 107,662 by July 3. However, the model predicts hospitalizations and deaths will remain stable through the beginning of July. (Carbajal, Becker's Hospital Review, 6/22)