Summary
Streptococcus pneumoniae (the pneumococcus) causes pneumonia, sepsis and meningitis, particularly affecting vulnerable groups like young children, the elderly, and people with weakened immune systems (e.g. adults living with HIV). While effective vaccines are available for young children, their high cost means adults often remain unprotected, with pneumococcus representing a very common cause of serious infections and death, particularly in sub-Saharan Africa (sSA) where it has been linked to several outbreaks in the past years. Improved vaccine-based control of the pneumococcus would help to decrease antibiotic use linked to infections and reduce the spread of antimicrobial resistance.
We will tackle these challenges by developing a more affordable pneumococcal vaccine for adults based on protein antigens. All humans have antibody responses to pneumococcal proteins that can prevent infections caused by multiple pneumococcal serotypes. Our data, obtained using samples from Ghanaian and UK adults, show that antibody levels to these protein antigens fall with age. We reason that boosting antibody levels to these protein antigens by vaccination could protect older adults from pneumococcal disease. Using our protein array, we will compare systemic antibody responses to 250 pneumococcal proteins among 3 cohorts of subjects from Malawi: healthy adults, HIV infected and older adults (>65). The results will be compared with our existing data for Ghanaian and UK adults to identify against which proteins antibody levels fall with age across all three countries. These proteins will be used as a potential vaccine to reduce both pneumococcal disease and antimicrobial resistance in high-risk adults.