NBP-606

Ethiopia introduced the 10-valent pneumococcal conjugate vaccine (PCV10, GlaxoSmithKline plc.) in 2011 and switched to 13-valent vaccine (PCV13, Pfizer Inc.) in 2020. In 2023, we conducted a study in four settings in Ethiopia to determine the vaccine coverage, residual vaccine-type carriage prevalence, serotype distribution, and factors associated with carriage across all age groups.

A cross-sectional survey was conducted in urban and rural areas of eastern and southwest Ethiopia in 2023. In total, 50 participants in each of 10 age groups (<1, 1-2, 3-4, 5-9, 10-14, 15-19, 20-39, 40-49, 50-59, and ≥ 60 years) were randomly selected using population registers in Harar, Kersa and Gilgel Gibe demographic surveillance systems, and using random GPS points for Jimma city. After informed consent, data on socioeconomic characteristics and vaccine coverage were collected. A single nasopharyngeal swab was collected and cultured for pneumococci. Pneumococci were serotyped using latex agglutination and confirmatory Quellung reaction.

A total of 2006 participants were enrolled. The age-standardized population prevalence of pneumococcal carriage (all serotypes) in rural settings was 56 % (95 %CI 48-64 %) in the east and 26 % (95 %CI 20-31 %) in the southwest, and in urban settings, 15 % (95 %CI 11-20 %) in the east and 16 % (95 %CI 12-19 %) in the southwest. PCV13 serotype carriage prevalence among children aged <5 years ranged from 7.4 to 9.3 % in the urban areas, to 16-22 % in the rural areas. Coverage of the third dose of PCV, recorded in vaccination cards of participants aged <5 years, was 49 %-87 % in the urban areas; it was much lower at 13-22 % in the rural areas.

There is considerable residual circulation of vaccine serotypes in Ethiopia, particularly in rural areas and the east, and low vaccine coverage. Pneumococcal epidemiology varies by geographical region and urban/rural setting, implying an unequal burden of pneumococcal disease across the country 12 years post-PCV introduction.

Pneumococcal vaccination plays a crucial role in the prevention of bacterial respiratory infections caused by Streptococcus pneumoniae. Pneumococci are responsible for diseases such as pneumonia, sinusitis and acute otitis media and can cause serious invasive infections such as meningitis and bacteraemia. Pneumococcal pneumonia leads to increased morbidity and mortality, particularly in patients with chronic lung diseases such as chronic obstructive pulmonary disease (COPD). The introduction of 13-valent conjugate vaccines (pneumococcal conjugate vaccine 13 [PCV13]) has significantly reduced the burden of disease. However, infections caused by serotypes not covered by PCV13 continue to occur. Current vaccines such as the 20-valent conjugate vaccine (PCV20) provide extended serotype coverage and have shown a robust immune response in clinical trials. The recently updated recommendations of the German Standing Committee on Vaccination (Ständige Impfkommission, STIKO) include the use of PCV20 for all indication categories in adults, which represents a simplified and more effective vaccination strategy. Future developments include vaccines with even broader serotype coverage and improved immunological properties; these are expected to further reduce the burden of pneumococcal disease. Improving vaccination uptake and increasing vaccination rates, particularly among at-risk groups, remain key objectives to protect public health in the long term.