Using pneumococcal carriage and invasiveness to inform vaccine policy in tropical Africa

Pneumococcal conjugate vaccines have had a tremendous impact on pneumonia, meningitis and sepsis among children in the UK and USA and early studies suggest they also work in Africa. However, they are expensive and their effects are not always the same in each area. It is essential that pneumococcal disease is monitored after the vaccine is introduced but African countries are unable to afford the surveillance.

I propose an affordable alternative to monitoring the impact of a vaccine. We can observe whether the vaccine is interrupting transmission of pneumococci by sampling the nasal mucous of healthy people and we can use mathematical models to predict how much disease is being averted and how the programme could be optimised. I will undertake nasal surveys in the Democratic Republic of the Congo, Ethiopia and Nigeria and share the results with decision-makers in the countries’ governments. Predicting disease levels entirely from nasal surveys is novel so I propose validation studies in epidemiology and genomics to test its validity.