School-going children bring home a virus that causes severe pneumonia in infants

Infants are highly susceptible to severe pneumonia from a virus called respiratory syncytial virus or RSV.  Identifying who infects infants with this virus is important in designing the best options for preventing such disease. In a study undertaken in Kilifi, on the Kenyan coast, researchers have clearly shown that older siblings, especially those attending school are an important source of RSV infection to the infants in their homes. The study, undertaken by KEMRI-Wellcome Trust Research Programme, found that school going siblings are frequent introducers of RSV into homes.

RSV is a major cause of childhood acute lower respiratory tract infection (LRTI). Globally, the virus is associated with 34 million cases of severe LRTI and up to 199,000 deaths each year among children aged less than five years. The real burden of RSV is likely to be higher as hospitalization with RSV in the first year of life has been shown to increase the risk of readmission with wheezing pneumonia.

Other studies have shown that approximately 60% of all newborn are infected with RSV during their first year of life. In this study conducted in a rural set up in a developing country, 64% of the infants were infected in the homes studied.

Of these infants, 54% acquired their infection from other family members. Older siblings and cousins were the first ones to be infected in the family before the infant acquired the infection. Most of the elder siblings (10/11) were attending school. The study showed that mothers and fathers were less likely to introduce RSV into the homes.

RSV outbreaks in Kilifi occur annually peaking in the first quarter of each year. The study was set to coincide with the onset of an RSV season. Homes were carefully selected to include those with young infants, with no prior exposure to RSV infection and at least one older child. Overall 84% of homes reported one or more episodes of RSV with 72% of these experiencing quick spread within the family members. This demonstrates how contagious this virus is.

Currently there are no RSV vaccines approved for infants, therefore alternative strategies are important in protection of infants.

‘Knowing from whom the infant gets RSV infection is important in informing the debate on designing alternative control strategies against RSV’ says Patrick Munywoki, an Infectious Disease Epidemiologist.

The current results supports vaccination of school going children or targeting siblings with newborns in the family as options of delaying the first RSV infection in infants so that it occurs when the newborns are at a less risk of severe LRTI. This is in addition to the direct benefits of protection to the recipient of an RSV vaccine.