We study pneumococcal infection that are major contributors to morbidity and mortality world wide. New conjugated pneumococcal vaccines have been launched targeting only a minor proportion of pneumococcal strains circulating in the society. We aim to investigate the microbiome of the nasopharynx among healthy children as compared to those with a respiratory tract infection, using metagenomic as well as metatranscriptomic approaches in order to understand the etiology of respiratory tract infections that are important for diagnostics, prevention, and treatment, as well as to identify potential biomarkers as prognostic markers. Here, we will study the metagenomics of the project including bacterial, viral and human RNA/DNA.