Respiratory syncytial virus behind 100,000 child deaths

Respiratory syncytial virus (RSV) was responsible for more than 100,000 deaths in children under five across the globe in 2019, according to a study by Australian and international researchers.

The researchers examined RSV disease burden in narrow age brackets, reporting that there were over 45,000 deaths in infants under six months old in 2019, with one in five of the total global cases of RSV occurring in this age group.

“RSV is the predominant cause of acute lower respiratory infection in young children and our updated estimates reveal that children six months and younger are particularly vulnerable, especially with cases surging as COVID-19 restrictions are easing around the world and the majority of the young children born in the last two years have never been exposed to RSV (and therefore have no immunity against this virus). With numerous RSV vaccine candidates in the pipeline, our estimates by narrower age ranges help to identify groups that should be prioritised, including pregnant people, so that children in the youngest age groups can be protected, similarly to current strategies which offer vaccines for whooping cough, typhoid and tetanus to pregnant people,” said Harish Nair, University of Edinburgh, UK, co-author of the paper published in The Lancet.

Across the globe in 2019, there were 33 million RSV-associated acute lower respiratory infection episodes in children under five years old, leading to 3.6 million hospital admissions, 26,300 in-hospital deaths and 101,400 RSV-attributable deaths overall (including community deaths), according to the study authors. This accounts for one in 50 or 2% of annual deaths from any cause in this age range.

For children under six months old, there were 6.6 million RSV-associated acute lower respiratory infection episodes globally in 2019. There were 1.4 million hospital admissions, 13,300 hospital deaths and 45,700 overall deaths attributable to RSV in this age range, accounting for one in 50, or 2.1% of annual deaths from any cause.

Based on estimates of in-hospital versus overall RSV mortality rates, globally only 26%, or approximately one in four RSV-associated deaths, occur in a hospital. This is particularly apparent in low- and middle-income countries, where the in-hospital case-to-fatality ratio for children under five is 1.4%, compared to 0.1% in high-income countries. Overall, 97% of RSV deaths in children under five occurred in low- and middle-income countries.

“Our study estimates that three-quarters of RSVs deaths are happening outside of a hospital setting. This gap is even greater in LMICs, especially in children under six months old, where more than 80% of deaths are occurring in the community. This reflects the fact that access and availability to hospital care are still limited in these regions. Early identification of cases in the community and referral for hospital admission of sick children (particularly those with low oxygen saturation in peripheral blood), and universal effective and affordable immunisation programmes will be vital going forward,” said Xin Wang, co-author of the study, Nanjing Medical University, China and University of Edinburgh, UK.

The authors acknowledged some limitations with this study. Variations in factors such as study setting, exact case definition for acute lower respiratory infection (ALRI), healthcare access and seeking behaviour, and eligibility for RSV testing could affect estimates of mortality figures produced in the modelling. The breakdown by age bands was also limited by the data available for the study. In addition, all data were collected before the COVID-19 pandemic; it is unknown how the COVID-19 pandemic could affect RSV disease burden in the long term.

Image credit: ©stock.adobe.com/au/jarun011