Researchers Identify Worldwide Trends for Respiratory Virus Rates in Children

You Li, PhD

While respiratory syncytial virus (RSV) is the predominant viral pathogen linked to acute lower respiratory infections (ALRI) in children younger than 5, there is little reported on the national estimates of RSV-associated ALRI hospitalizations.

An international team including researchers from the UK, US, and France, led by You Li, PhD, Center for Global Health, Usher Institute, University of Edinburgh, generated national level estimates for RSV-associated ALRI hospitalizations in children younger than 5 years old.

The investigators included data for RSV and ALRI hospitalization in children using systematic literature reviews and inpatient databases representing 58 countries.

Overall, they identified 334 studies with 1985 data points—defined as an individual estimate for 1 age group and 1 year for each study—accounting for 398 million (59%) of the 677 million children younger than 5 worldwide.

The investigators used both a rate-based method and a proportion-based method to estimate a national RSV-associated ALRI hospitalizations in children younger than 5 in 2019. The rate-based method synthesized data for laboratory-confirmed RSV-associated ALRI hospitalization rates using a spatioemporal Gaussian process meta-regression (ST-GPR).

The proportion-based method applied data for RSV positive proportions among ALRI hospitalization envelopes which including the total disease burden of ALRI hospitalizations of any cause, using a Bayesian regularized trimmed meta-regression (MR-BRT).

They then reported estimates when applicable using both methods to provide a plausible range for each of the 58 countries.

The investigators found the number of annual national RSV-associated ALRI hospitalizations for 29 countries using the rate-based method and 42 countries using the proportion-based method, while the median number of RSV-associated ALRI hospitalization in the patient population was 825,000 (IQR, 1.97-48.01). The median rate of RSV-associated ALRI hospitalizations was 514 (IQR, 339-886) hospitalizations per 1000 children younger than 5.

However, despite large variations among countries, with a high proportion of the RSV-associated ALRI hospitalizations in infants younger than 1 in all countries (median proportion 45%; IQR, 32-56).

In 272 (76%) of the 358 years included in the analysis, the RSV-associated ALRI hospitalization rate ranged from 0.8-1.2 times the country’s median yearly rate.

There was a general agreement found between estimates by the 2 models, with the exceptions of India, Kenya, and the Philippines.

“By incorporating data from various sources, our study provides robust estimates on national level burden of RSV-associated ALRI hospitalization in children aged younger than 5 years,” the authors wrote. “These estimates are important for informing policy for the introduction of RSV immunizations and also serve as baseline data for the RSV disease burden in young children.”

The study, “National burden estimates of hospitalizations for acute lower respiratory infections due to respiratory syncytial virus in young children in 2019 among 58 countries: a modelling study,” was published online in The Lancet Respiratory Medicine.