Maternal immunisation against Group B Streptococcus: a global analysis of health impact and cost-effectiveness

Abstract

AbstractBackgroundGroup B Streptococcus (GBS) can cause invasive disease (iGBS) in young infants, typically presenting as sepsis or meningitis, and is also associated with stillbirth and preterm birth. GBS vaccines are under development, but their potential health impact and cost-effectiveness have not been assessed globally.MethodsWe assessed the health impact and value (using net monetary benefit, NMB, which measures both health and economic effects of vaccination into monetary units), of GBS maternal vaccination across 183 countries in 2020. Our analysis uses a decision-tree model, combining risks of GBS-related outcomes from a Bayesian disease burden model with estimates of GBS related costs and Quality-Adjusted Life Years (QALYs) lost. We assumed 80% vaccine efficacy against iGBS and stillbirth, following the WHO Preferred Product Characteristics, and coverage based on the proportion of pregnant women receiving at least four antenatal visits. One dose was assumed to cost $50 in high-income countries, $15 in upper-middle income countries, and $3.50 in low-/lower-middle income countries. We estimated NMB using alternative normative assumptions that may be adopted by policy makers.FindingsVaccinating pregnant women could avert 214,000 (95% uncertainty range 151,000 – 457,000) infant iGBS cases, 31,000 deaths (14,000 – 67,000), 21,000 (9,000 – 52,000) cases of neurodevelopmental impairment, and 23,000 (10,000 – 58,000) stillbirths. A vaccine effective against GBS-associated prematurity might also avert 172,000 (13,000 – 378,000) preterm births. Globally, a 1-dose vaccine programme could cost $1.7 billion but save $385 million in healthcare costs. Estimated global NMB ranged from $1.1 billion ($-0.2 – 3.8 billion) to $17 billion ($9.1 – 31 billion).InterpretationMaternal GBS vaccination could have a large impact on infant morbidity and mortality globally and at reasonable prices is likely to be cost-effective.