Some sixty "Opiod Overdose Kits" have been added defibrillator boxes in Bridgewater State University dorms and academic buildings like this one. Tovia Smith / NPR hide caption

"I am frustrated that despite all of our efforts, we haven't been able to identify the cause of this mystery illness," said Dr. Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases at the Centers for Disease Control and Prevention. James Leynse/Corbis/Getty Images hide caption

Shared scooters and bicycles are spreading to several major U.S. cities while policymakers are scrambling to find ways to ensure that riders are safe. David Paul Morris/Getty Images hide caption

David Vetter plays in the enclosed plastic environment that he had to stay in to survive. Bettmann/Bettmann Archive hide caption

A 12-year-old Iranian refugee girl, who had tried to set herself on fire with petrol, rests in a bed in Nauru, where nearly 1,000 refugees and asylum seekers have been sent by the government of Australia. Mike Leyral/AFP/Getty Images hide caption

Vera Rahayu Putri and her husband Faizal, who goes by one name, survey earthquake damage in their Palu neighborhood of Petobo, now covered by mudslides. Putri€'s 9-year-old son, Raldi, is among thousands of children who are unaccounted for. Lauren Frayer/NPR hide caption

Delayed pushing made no difference in whether first-time mothers had a cesarean section, a large study finds. Getty Images hide caption

14-year-old Caydden Zimmerman has been living in a homeless shelter in Boise, Idaho, for a couple of months with his 11-year-old brother and his grandma. About 2.5 million children in America are homeless. Amanda Peacher/Boise State Public Radio hide caption

Alex Schwartzman, a law student at George Washington University in Washington, D.C., is one of only 8 to 39 percent of college students who get the flu shot in a given year. Mary Mathis/NPR hide caption

More kids are eating at fast-food chains like McDonald's, according to a new study, but parents are buying the healthier side options only about half the time. Miguel Candela/SOPA Images/LightRocket via Getty Images hide caption

This adult Anopheles gambiae mosquito — the kind that spreads malaria — was genetically modified as part of the study. Andrew Hammond hide caption

James and Rosina Komape. In 2014, their 5-year-old son, Michael, fell in a pit latrine at school and drowned. Krista Mahr for NPR hide caption

This did not really happen. Cows' heads did not emerge from the bodies of people newly inoculated against smallpox. But fear of the vaccine was so widespread that it prompted British satirist James Gillray to create this spoof in 1802. Institute of the History of Medicine, Johns Hopkins University hide caption

Of parents who tell pollsters their teens have trouble sleeping, 23 percent say the kids are waking up at night worried about their social lives. A third are worried about school. All-night access to electronic devices only aggravates the problem, sleep scientists say. 3photo/Getty Images hide caption

Walter Mischel, a psychologist who devised the marshmallow test, explained what it really means. Marcie LaCerte/NPR hide caption

Supreme Court nominee Judge Brett Kavanaugh during the second day of his Supreme Court confirmation hearing on Capitol Hill. Win McNamee / Getty Images hide caption

"If you do say, 'Yes, my child has seen a counselor or a therapist or a psychologist,' what does the school then do with that?" asks Laura Goodhue, who has a 9-year-old son on the autism spectrum and a 10-year-old son who has seen a psychologist. Andrea D'Aquino for NPR hide caption

Drinking water samples from homes in southwestern Puerto Rico are tested at Interamerican University of Puerto Rico in San German. Rebecca Hersher/NPR hide caption

Yogurt selections like this one at a Los Angeles 365 by Whole Foods Market store are getting larger, but a new U.K. study warns that many contain lots of added sugar. Patrick T. Fallon/Bloomberg via Getty Images hide caption