Chinese travelers at a railway station in Beijing, China, wear face masks to protect themselves from the new coronavirus on Jan. 21, 2020. The virus was first identified in Wuhan, China, in Dec. 2019, and since then has quickly spread worldwide. Kevin Frayer/Getty Images hide caption
Students wear masks at a school in Baghdad. Anadolu Agency/Anadolu Agency via Getty Images hide caption
Dr. Chizoba Barbara Wonodi is director of Johns Hopkins University's International Vaccine Access Center for Nigeria. Dr. Chizoba Barbara Wonodi hide caption
People attend a SoulCycle class under an outdoor tent in September in New York City. Noam Galai/Getty Images hide caption
A woman receives medication at a clinic offering antiretroviral drugs for HIV patients in Ga-Rankuwa, South Africa. STEPHANE DE SAKUTIN/AFP via Getty Images hide caption
Pretty Mkhabela, a HIV-positive sex worker in South Africa, gets antiretroviral drugs delivered to her house as part of a campaign to maintain treatment for HIV-positive patients during the pandemic. A new drug called cabotegravir could give women more options to protect themselves from HIV infection. Bram Janssen/AP hide caption
When it's cold outside, is it safe to bring a socially distanced gathering into your house if the windows are open for a short bit and then shut so indoor temperatures don't plummet? We answer this question below. Tessa Bunney/Corbis via Getty Images hide caption
An illegal roadside graveyard in northeastern Namibia. People in the townships surrounding Rundu, a town on the border to Angola, are too poor to afford a funeral plot at the municipal graveyard — and resorted to burying their dead next to a dusty gravel road just outside of the town. Brigitte Weidlich/AFP via Getty Images hide caption
Left: Xi Lu traveled to Wuhan from London in January to spend Lunar New Year with his parents, having not shared the holiday with them in over 7 years. Lin Yang, an epidemiologist at Hong Kong Polytechnic University, traveled to Wuhan to visit her parents for the Lunar New Year. And then ... they couldn't get back home because of the quarantine. Xi Lu/ Lin Yang hide caption
Air conditioners on a building. Scientists say there has been too little research into the role of heating, ventilation and air conditioning systems in the spread of the coronavirus. Sami Sarkis/Getty Images hide caption
A fan wears a neck gaiter as he watches the Los Angeles Dodgers play at home against the San Francisco Giants last week. Gina Ferazzi/Los Angeles Times via Getty Images hide caption
Left: Jana De Brauwere, a contact tracer in California. Right: Rachel Saykpah, a nurse in Liberia who has overseen contact tracers in Africa since 2014. Jana De Brauwere; Rachel Saykpah hide caption
From left: Maria Nakalanda, Edward Arineitwe and Charles Batte are Ugandan health-care workers who've had to rethink their commute after their country announced transportation restrictions. Maria Nakalanda; Edward Arineitwe; Charles Batte hide caption