Epidemiological and clinical profile of viral respiratory infections in children under 5 years at pre- and post-COVID-19 era in Praia, Cabo Verde

Background: The coronavirus disease-19 (COVID-19) pandemic has affected global health, influencing the prevalence of different respiratory pathogens. The aim of this study is to evaluate the distribution of agents causing acute respiratory infections in children under 5 years old before and after the COVID-19 pandemic in Praia, Cabo Verde, and to describe associated clinical variables. Methods: Conducted at the University Hospital Dr. Agostinho Neto, this study replicated methods from a previous work from 2019 (Correia et al. 2021). Nasopharyngeal samples were analysed using FilmArray® Respiratory Panel 2.1 (BioFire) to identify agents of acute respiratory infections. Molecular identification of human respiratory syncytial virus subtypes was performed using a real-time duplex reverse transcription polymerase chain reaction. Statistical analysis was performed using IBM SPSS version 29 and R 3.5.1 software. Results: In 2022, 86.5% (83/96) of nasopharyngeal samples were positive for at least one pathogen. Human rhinovirus/human enterovirus was the most frequent agent, followed by human respiratory syncytial virus, adenovirus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Co-infections were observed in 43.3% of positive cases. Infection rates were significantly higher in children under 1 year of age, particularly for SARS-CoV-2 and human respiratory syncytial virus. Seasonal variations were observed, with human respiratory syncytial virus predominating in November, SARS-CoV-2 in January and human parainfluenza virus-4 in May. Molecular analysis of human respiratory syncytial virus revealed a shift in subtype prevalence, with both human respiratory syncytial virus-A and -B co-circulating in the pre-pandemic period, whereas only human respiratory syncytial virus-B was detected in the post-pandemic period. Conclusion: Our data indicate changes in the distribution of respiratory viruses in the post-pandemic period compared to pre-pandemic period. The high prevalence of co-infections highlights the complexity of acute respiratory infection aetiology, emphasising the need for enhanced respiratory virus surveillance systems in Cabo Verde. Identifying seasonal trends and risk factors can contribute to targeted interventions and improved public health strategies to mitigate the burden of acute respiratory infections in young children.