Respiratory syncytial virus (RSV) and other viruses now appear to be the main causes of severe childhood pneumonia in low- and middle-income countries, highlighting the need for vaccines against these pathogens, according to a study from a consortium of scientists from around the world, led by a team at the Johns Hopkins Bloomberg School of Public Health.

Respiratory syncytial virus (RSV)
using indirect immunofluorescence technique/CDC

Pneumonia is the leading cause of death worldwide among children under 5 years old, with about 900,000 fatalities and more than 100 million reported cases each year. This makes pneumonia a greater cause of childhood mortality than malaria, tuberculosis, HIV, Zika virus and Ebola virus combined.

The study, published June 27 in The Lancet, was the largest and most comprehensive of its kind since the 1980s. It included nearly 10,000 children in seven African and Asian countries. After testing for viruses, bacteria, and other pathogens in children with severe hospitalized pneumonia—and in community children without pneumonia—the study found that 61 percent of severe pneumonia cases were caused by viruses led by RSV, which alone accounted for 31 percent of cases.
“Prior to this study, we didn’t know which specific viruses and bacteria are now causing most of the severe childhood pneumonia cases in the world, but public health organizations and vaccine manufacturers really need that information to work toward reducing the substantial childhood mortality that pneumonia still causes,” says study co-principal investigator Maria Deloria Knoll, PhD, a senior scientist in the Bloomberg School’s Department of International Health, and associate director of science at the Johns Hopkins International Vaccine Access Center (IVAC).