Invasive Pneumococcal Disease and Carriage among Children with Sickle Cell Disease in Ghana: A Post-vaccination Study

PROJECT SUMMARY Pneumococcal carriage is the precursor for development of pneumococcal disease, and is also responsible for transmission of the organism from person-to-person. Children with Sickle Cell Disease (SCD) are particularly susceptible to invasive pneumococcal disease (IPD) due to the i n a b i l i t y of their defective immune system to effectively handle encapsulated bacteria. This has led to the recommendation of anti-pneumococcal prophylaxis for SCD children including the administration of penicillin and the 23-valent polysaccharide vaccine (PPV23) in the past. Though these prophylactic measures decreased the rate of IPD among SCD children, breakthrough disease still occurred, mostly in children aged <3 years. In the last decade, Pneumococcal Conjugate Vaccines (PCVs) have become available in about 80% of the countries in sub-Saharan Africa. Epidemiological evidence from various studies indicate that PCVs can cause a shift in the distribution of pneumococcal serotypes usually towards non- vaccines types in both carriage and disease. In areas of high SCD prevalence in sub-Saharan Africa, pneumococcal surveillance data following introduction of PCVs remain scarce. The goal of this proposed study is to understand the epidemiology of pneumococcal carriage and invasive disease among children with SCD in the post-conjugate vaccine era in Ghana. To address this goal, we will execute three specific aims as follows: (i) to determine the frequency of pneumococci acquisition in SCD children vaccinated with PCV13 and evaluate the common serotypes carried and their persistence. (ii) to determine the incidence of IPD and the causative serotypes among children with SCD. (iii) to evaluate the antibiogram of pneumococci isolated from children with SCD and describe the penicillin and / or multidrug resistant clones. Information from the study would be useful in the prevention and management of pneumococcal infections among children with SCD in Ghana.