After rising for decades in the United States, opioid overdose deaths have been declining dramatically since 2023, with the annual rate of fentanyl overdose deaths dropping by more than a third by the end of 2024. What’s behind this sudden decline? In this Policy Forum, Kasey Vangelov and colleagues evaluate the evidence for an international supply shock in fentanyl in 2023 and conclude that it could be responsible for the steep decline in overdose deaths. Studying the ups and downs of an illegal drug economy is difficult, but the researchers use data from several sources, including a spike in U.S.-based Reddit users’ reports of a fentanyl drought in mid-to-late 2023. Fentanyl seized during this period shows a concurrent decline in purity and seizures themselves fell during the period, despite being an intense focus of law enforcement. In Canada, supply indicators of fentanyl precursors from China declined at the same time. Together, this evidence indicates that supply disruption may be behind the drop off in fentanyl deaths. “The incentive to restore the illicit fentanyl trade will persist as long as there is demand for the drug …” Vangelov et al. write, adding that “…it may be wise to use the current drought as an opportunity to ramp up the prevention and treatment programs that have evidence of decreasing demand.”

IDH-mutant glioma, caused by abnormalities in a specific gene (IDH), is the most common malignant brain tumor among young adults under the age of 50. It is a refractory brain cancer that is difficult to treat due to its high recurrence rate. Until now, treatment has focused primarily on removing the visible tumor mass. However, a Korean research team has discovered for the first time that normal brain cells acquire the initial IDH mutation and spread out through the cortex long before a visible tumor mass harboring additional cancer mutations forms, opening a new path for early diagnosis and treatment to suppress recurrence.

A new study suggests that the connection between coronary artery calcification — a measure of calcium buildup in the arteries — and bone mineral density may be driven in part by shared genetic factors, rather than one directly causing the other. By highlighting the biological pathways that influence both vascular and bone health, the findings provide researchers with new directions for understanding age-related changes in the heart and skeleton.

Maternal prenatal stress related to natural and human-made disasters can lead to epigenetic modifications in offspring, according to a narrative review published in Harvard Review of Psychiatry, part of the Lippincott portfolio from Wolters Kluwer. The review appears in a special issue on preventative psychiatry.

A commentary coauthored by IIASA experts and senior representatives from the UN and the international statistics community discusses the implications of recent changes to the Demographic and Health Surveys (DHS) program and highlights the importance of integrating citizen science more fully into official data systems.

About The Study: This study found that maternal influenza and tetanus-diphtheria-acellular pertussis (Tdap) vaccinations were associated with reduced influenza- and pertussis-related hospitalization or emergency department visits in infants younger than 6 months. Given the low vaccination coverage, it is crucial to implement maternal vaccination campaigns to enhance infant health outcomes.

About The Study: In this interim reporting of respiratory syncytial virus prefusion F (RSVpreF) vaccine safety in a large cohort of pregnancies with vaccine-seeking behavior, this study found no statistically significant increases in any prespecified safety outcomes compared with unvaccinated pregnancies.