Abdoulie Bojang, a higher scientific officer working in the PregnAnZI team is the first author of a recently published paper showing the seasonal patterns of pneumococcal nasopharyngeal colonization in a cohort of individuals participating in the Sibanor Vaccine Trial, a cluster randomized pneumococcal conjugate vaccine trial conducted in Sibanor few years ago.
Dr Anna Roca, senior author of the publication, comments on the importance of maximising outputs from ongoing studies to ensure that “young scientists have the opportunity to publish as first authors”.

Carriage studies are becoming increasing useful measures in assessing impacts of Pneumococcal conjugates vaccines deployed widely in sub-Saharan Africa and in other developing countries.  Hence it is paramount we strengthen our understanding of factors other than vaccination that can influence trends in pneumococcal colonisation as this information is necessary to interpret the results of impact studies.

The primary aim of the analysis reported in this paper was to determine the impact of season on pneumococcal carriage in The Gambia, as per the tropical characteristics of the country with two marked annual seasons - one dry and one rainy. For this purpose, we used the results obtained from nasopharyngeal swabs (NPS) collected over a period of 20 months from a cohort of individuals participating in the Sibanor Vaccine Trial.
The key findings for the study was that prevalence of carriage was significantly higher during the dry season compared to the rainy season for any pneumococcal carriage, pneumococcal vaccine serotype carriage and non-vaccine serotype carriage. Such results underpin the importance of considering the potential of external factors, specifically the role of seasonality, when designing impact studies and interpreting their results.

Abdoulie Bojang commented that “this study brings to light a very important factor that need to be considered when designing or interpreting impact studies relating to Streptococcus pneumoniae a major cause of pneumonia, meningitis and febrile bacteraemia in our sub-region”.

This article was first published on: PLOS ONE | DOI:10.1371/journal.pone.0129649