Epidemiology and Public Health Implications of Streptococcus pneumoniae Infections among High-Risk Populations in Nigeria: A Narrative Review

Abstract

Streptococcus pneumoniae remains an important cause of morbidity and mortality globally, with a disproportionate burden among populations at increased risk of severe disease. These include age-defined groups, such as children under 5 years old and older adults, as well as immunocompromised populations, including people living with HIV/AIDS, individuals with malignancies, and those receiving immunosuppressive therapies. Additional clinical and social factors, including sickle cell disease, diabetes, malnutrition, limited healthcare access, and suboptimal vaccination coverage, may further increase vulnerability to pneumococcal disease. In Nigeria, these interacting vulnerabilities occur within a health system characterised by diagnostic limitations, inequitable access to care, and persistent gaps in pneumococcal disease surveillance and prevention. This narrative review synthesises available evidence on the epidemiology, risk factors, clinical manifestations, diagnosis, antimicrobial resistance, prevention, and public health implications of S. pneumoniae infections among high-risk populations in Nigeria, with particular attention to age-defined groups, immunocompromised populations, and individuals with underlying conditions associated with increased susceptibility to severe pneumococcal disease. To mitigate this burden, Nigeria must integrate pneumococcal monitoring into the National Integrated Disease Surveillance and Response (IDSR) framework. Key priorities include expanding molecular diagnostic capabilities and monitoring the coverage and efficacy of pneumococcal vaccines. Improving pneumococcal disease control in Nigeria requires stronger surveillance and laboratory capacity, alongside equitable vaccination and better antimicrobial stewardship. Contemporary national data are also needed to guide future vaccine policy.