Epidemiology of human parainfluenza virus serotypes among children under five with acute respiratory infection in Cte dIvoire, 2022-2024

Acute respiratory infections (ARI) are a major health threat, leading to many hospitalizations in children. Human Parainfluenza Virus (HPIV) infections are the second most common cause of hospitalization in children under 5, after Respiratory Syncytial Virus (RSV). To identify the epidemiological characteristics of HPIV infection in Côte d'Ivoire, a total of 7332 nasopharyngeal swabs were collected from patients under 5 years of age seen in consultation for influenza-like illness (ILI) or severe acute respiratory infection. Multiplex RT qPCR was used to detect HPIV serotypes (HPIV-1, HPIV-2 and HPIV-3). The overall positivity rate was 2.41% (177/7332). Of the positive cases, 60 (33.9%) were of serotype 1.33 (18.6%) of serotype 2 and 84 (47.4%) of serotype 3. Over 72% (128/177°) of positive cases were observed in children aged between 0 and 12 months. HPIV were detected throughout the study years, with peaks observed during the long dry and rainy seasons. This study highlights the importance of HPIV, especially HPIV-3, in ARI in children under five in Côte d'Ivoire. The incidence was particularly high among infants, with seasonal variations in distribution. These results underline the need to strengthen viral surveillance systems, and could help guide future vaccination and treatment strategies. Key words: Parainfluenza virus, serotypes, epidemiology, children under 5, Côte d'Ivoire.