# Bronchiolitis in children ≤ 12 months during the pre-flu season of 2024: A case series

## TL;DR

A case series in 2024 found that most bronchiolitis cases in young children were caused by influenza A, not the expected RSV outbreak.

## Contribution

The study identified an unexpected predominance of influenza A over RSV in causing severe bronchiolitis in children.

## Key findings

- Influenza A was identified in 60% of bronchiolitis cases, while RSV was present in only 20%.
- All children responded well to symptomatic treatment as per existing guidelines.
- Severe bronchiolitis was observed despite no significant differences in demographics compared to previous years.

## Abstract

In March 2024, the National Institute for Communicable Diseases (NICD) warned against a respiratory syncytial virus (RSV) outbreak during the pre-flu season, 2024. Globally, RSV is responsible for most respiratory infections in young children. Since April 2024, we have noticed a more severe presentation of children with bronchiolitis at the National District Hospital, Bloemfontein. We aimed to investigate the causative organism/s and the appropriateness of the treatment guidelines in our setting.

A retrospective file review was carried out as part of the normal audit process. All children admitted with bronchiolitis during the 4-week study period were included in the case series. Ethical approval was obtained from relevant authorities.

Ten children ≤ 12 months presented with bronchiolitis symptoms. The Modified Tal Score was measured, with values between 8 and 12, indicating moderate and severe bronchiolitis in all cases. The demographics regarding gender, nutrition and vaccination status did not differ from previous years. Influenza A was identified in 60% of the cases, with RSV in only 20% of the cases. All the children responded well to symptomatic treatment and recovered.

Most bronchiolitis cases were caused not by the predicted RSV outbreak but by Influenza A.

Despite presenting with severe symptoms, all the children responded to symptomatic treatment as set out in our guidelines.