Researchers identified a biomarker that could predict COVID-19 mortality, children lost roughly a third of a school year to the pandemic, and more in this week's roundup of COVID-19 news.

• Paxlovid rebound may occur in a higher percentage of patients than previously reported, according to a new study published in Clinical Infectious Diseases. Previously, researchers from Pfizer said that rebound had occurred among 2.3% of patients who received Paxlovid and 1.7% of the control group in the clinical trial. In the new study, researchers analyzed 170 patients who either received Paxlovid or a placebo to determine the rate of rebound, which was defined as when a person tests negative for COVID-19 before experiencing a "temporary return of symptoms with or without a positive test." In total, 14.2% of the patients who took Paxlovid tested positive again after originally testing negative, and 18.9% had their symptoms return. In comparison, 9.3% of patients in the control group reported a viral rebound, and 7% reported a symptom rebound. This is the "best data so far on rate of symptomatic rebound after Paxlovid, despite limitations," said Walid Gellad, director of the University of Pittsburgh's Center for Pharmaceutical Policy and Prescribing. "Not rare. Not 5 percent." According to the researchers, they will test for "any virus specific or host specific factors" that could affect the rebound phenomenon in the study's next phase. (Twenter, Becker's Hospital Review, 2/24)

• With the federal COVID-19 public health emergency (PHE) slated to end in May, several U.S. states are also winding down their own statewide emergency declarations — signaling an end to governors' expanded legal powers during the pandemic. In California, Gov. Gavin Newsom (D) signed a proclamation to officially end the state of emergency, saying "the condition of extreme peril to the safety of persons and property … no longer exist." In Illinois, the state's emergency order will end in May alongside the federal PHE. Rhode Island and Delaware both recently extended their COVID-19 emergency orders while public officials in New Mexico are considering whether to extend the state's order beyond its Friday expiration date. Although Texas has not had any major COVID-19 restrictions for a while, Gov. Greg Abbott (R) said he intends to keep the state's emergency order in place until the state legislature passes a law to prevent local governments from mandating virus restrictions on their own. (Beam, Associated Press, 2/28)

• In a new preprint study published in Research Square, researchers have identified renalase as a potential biomarker that could independently predict COVID-19 mortality in hospitalized patients. For the study, researched analyzed blood samples from 473 COVID-19 patients who were hospitalized between March 2020 and June 2020. In total, 366 patients survived, and 71 passed away. According to the researchers, patients who died had lower average renalase levels and trended toward higher levels of IL-1, IFNs, and KIM-1 compared to those who survived. Overall, the researchers identified age, patient gender, and mean renalase as significant predictors of mortality through a standard logistic regression model. (Kunkalikar, News Medical, 3/2)

• The COVID-19 pandemic caused children to lose roughly one-third of a school year's worth of knowledge and skills, according to a new study published in Nature Human Behavior — and even two years later, many students are still facing delays. For the study, researchers analyzed data from 42 different studies from 15 different countries published between March 2020 and August 2022. Overall, the researchers found that global education deficits equaled roughly 35% of a school year and remained "incredibly stable" even in the years after. In general, students saw more significant delays in mathematics than in reading, and students with lower socioeconomic status and in middle-income countries were more likely to experience setbacks in their learning. These learning delays and regressions may lead to worsening inequities that could also follow children into higher education and work, the researchers said. According to Thomas Kane, faculty director of the Center for Education Policy Research at Harvard University, without immediate and aggressive intervention to help students catch up, "learning loss will be the longest-lasting and most inequitable legacy of the pandemic." (Baumgaertner, New York Times, 1/30)

• Evidence against ivermectin's use as a COVID-19 treatment continues to stack up, with a new large, randomized trial showing that a higher dose of the drug given for a longer duration still failed provide benefit to patients with mild-to-moderate COVID-19. In the ACTIV-6 trial, 1,203 patients with confirmed COVID-19 were randomized to receive ivermectin (600 μg/kg for six days) or a placebo. Of the participants, the median age was 48 years, roughly 60% were women, and 75% were white. Overall, the median time to sustained recovery was the same for both groups at 11 days, and there was no difference in hospitalization, urgent or ED care, or death. In an accompany editorial, Kristen Bibbins-Domingo, editor-in-chief of JAMA where the trial results were published, and Preeti Malani, the journal's deputy editor, noted that a 2022 meta-analysis of 11 studies, as well as three randomized trials, have all found no benefit of using ivermectin to treat COVID-19 patients, despite proponents continuing to argue for its usage. "Today JAMA publishes a new trial of ivermectin treatment for mild to moderate COVID-19 that addresses the possibility that the existing literature may have missed the efficacy of ivermectin because the previously tested dose – approximately 400 μg/kg daily for 3 days – was insufficient," they wrote. "At a higher treatment dose – 600 μg/kg daily and longer treatment duration of 6 days, Naggie and colleagues again conclude that ivermectin is not beneficial for the treatment of COVID-19." (Susman, MedPage Today, 2/23)