From the article: "Sub-Saharan African countries account for about a third of the global burden of vaccine-preventable diseases. These diseases are responsible for a large proportion of deaths in children under the age of five. But there is a knowledge gap about the burden of vaccine-preventable diseases among HIV-infected and HIV-exposed children (HIV-negative children born to women with HIV) in sub-Saharan Africa. It’s important to know more about this because of the extra vulnerability of children infected with – and exposed to – HIV. It’s also essential because health care interventions such as vaccination programmes need to be based on evidence. We wanted to get a better understanding of the disease burden and to determine what kind of information is missing. We reviewed and analysed scientific literature about how children in sub-Saharan Africa have been affected by vaccine-preventable diseases since the advent of HIV in the 1980s. We wanted to find out how prevalent these diseases are among children who are infected by – or exposed to – HIV. We also wanted to know how many new infections are occurring each year and how many children are dying as a result. We looked for trends and the current burden of vaccine-preventable disease in the region."