virus

A parvovirus B19 infection can cause a facial rash in children, which is why the disease caused by the virus is sometimes called "slapped-cheek disease." Dr P. Marazzi/Science Source hide caption

An image of the hepatitis C virus Image made from a transmission electron microscopy. The virus is adept at evading the immune system. BSIP/Universal Images Group via Getty Images hide caption

Registered pharmacist Sapana Patel, loads a syringe with monkeypox vaccine at a pop-up vaccination site on Wednesday, Aug. 3, 2022, in West Hollywood, Calif. Richard Vogel/AP hide caption

People protest during a rally calling for more government action to combat the spread of monkeypox at Foley Square on July 21, 2022 in New York City. Jeenah Moon/Getty Images hide caption

Sikhulile Moyo, the laboratory director at the Botswana-Harvard AIDS Institute Partnership and a research associate with the Harvard T.H. Chan School of Public Health, headed the team that identified the omicron variant. Leabaneng Natasha Moyo hide caption

The numerals in this illustration show the main mutation sites of the delta variant of the coronavirus, which is likely the most contagious version. Here, the virus's spike protein (red) binds to a receptor on a human cell (blue). Juan Gaertner/Science Source hide caption

Hospitalizations and deaths from the coronavirus continue to increase this month, with the number of Americans who died in a single day from the illness surpassing 3,600. Jae C. Hong/AP 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

Research suggests that kids tend to get infected with the coronavirus less often, and have milder symptoms than adults. There's less consensus on how much kids can spread the illness. Dan Kenyon/Getty Images hide caption