OBJECTIVES: Cytomegalovirus (CMV) infection in healthy individuals is often mild or asymptomatic; however, a pregnant woman can pass CMV to her newborn, resulting in congenital cytomegalovirus (cCMV), the major infectious cause of sensorineural hearing loss and neurodevelopmental abnormalities in infants born in developed countries. There are no vaccines currently available to prevent CMV.
METHODS: We developed a static Markov model to evaluate the incremental impact of routine prophylactic vaccination in 16-40-year-old females, regardless of CMV serostatus, compared to no vaccination. Using conservative assumptions, efficacy against primary infection for the 3-dose vaccine regimen was 70% in the first 2 years then waned to zero over the next 5 years; no efficacy was assumed against non-primary infection. Health outcomes included CMV infections (primary and non-primary) and cCMV cases (symptomatic cCMV, neonatal death, and cCMV-related stillbirth) averted; number needed to vaccinate to prevent one case of CMV and cCMV were calculated. One-way sensitivity analyses assessed the robustness of specific parameter estimates.
RESULTS: In a fully-vaccinated cohort of 100,000 females, we expected a mean reduction of 3,238 (95% CrI:1,871-4,909) CMV infections and 105 (95% CrI:63-155) cCMV cases (including 10 [95% CrI:6-15] cases of symptomatic cCMV, 2 [95% CrI:1-3] neonatal deaths, and <1 cCMV-related stillbirth). To prevent one case of CMV and cCMV, 31 (95% CrI:20-53) and 955 (95% CrI:647-1,598) females need to be vaccinated, respectively. Probability of CMV reactivation in 16-40-year-old females was the most sensitive model parameter.
CONCLUSION: There is substantial US public health benefit associated with utilization of an effective CMV vaccine in 16-40-year-old females, regardless of serostatus. Several model parameters were based on assumptions and robust evidence will need to be generated. The model did not include potential transmission effects of vaccination. Furthermore, the efficacy and durability of a licensed vaccine, including against non-primary infection in seropositive individuals, are unknown and will be important considerations.
