OBJECTIVES: Cytomegalovirus (CMV) infection in healthy individuals is typically 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: A static Markov model was developed to evaluate the incremental impact of routine prophylactic vaccination in 16-40-year-old females in the UK, regardless of CMV serostatus, compared to no vaccination. Using conservative assumptions, efficacy against primary infection for a 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 parameter estimates.
RESULTS: In a hypothetical cohort of 100,000 fully vaccinated females, we estimated a mean reduction of 2,961 (95% CrI: 1,686-4,590) CMV infections and 83 (95% CrI: 48-125) cCMV cases (including 9 [95% CrI: 5-14] cases of symptomatic cCMV, 2 [95% CrI: 1-3] neonatal deaths, and <1 cCMV-related stillbirth). To prevent one case of CMV and cCMV, 34 (95% CrI: 22-59) and 1,204 (95% CrI: 797-2,076) females need to be vaccinated, respectively. Probability of primary CMV infection in 16-40-year-old females was the most sensitive parameter.
CONCLUSIONS: There is substantial public health benefit associated with utilization of an effective CMV vaccine in 16-40-year-old females in the UK, regardless of serostatus. Several model parameters were based on assumptions and robust evidence generation is needed. Furthermore, the efficacy and durability of a licensed vaccine, including against non-primary infection in seropositive individuals, are unknown and will be important considerations.
