Examination of scenarios introducing rubella vaccine in the Democratic Republic of the Congo. (December 2021)

• Record Type: Journal Article
• Authors: Cheng, Alvan; Frey, Kurt; Mwamba, Guillaume Ngoie; McCarthy, Kevin A.; Hoff, Nicole A.; Rimoin, Anne W.
• Is Part Of: Vaccine. Volume 9(2021)
• Publication Date: 2021-12
• Subjects: Rubella -- Congenital rubella syndrome -- Vaccine introduction -- Agent-based model
• DOI: 10.1016/j.jvacx.2021.100127
• Languages: English
• ISSNs: 2590-1362

Abstract

Highlights: Serosurvey data suggest R0 values for rubella in the DRC on the range 3 to 8. Supplementary immunization activities provide multi-decade reduction in burden. Post-vaccine introduction, burden will likely be concentrated in outbreaks. Abstract: Background: Rubella vaccine has yet to be introduced into the national immunization schedule of the Democratic Republic of the Congo (DRC); the current burden of congenital rubella syndrome (CRS) is unknown and likely to be high. An important consideration prior to introducing rubella containing vaccine (RCV) is the potential inverse relationship between RCV coverage and CRS incidence. Increasing RCV coverage will also increase in the average age of infection. Cumulative infections across all age groups will decrease, but the number of infections in age groups vulnerable to CRS may increase. Methods: Rubella transmission dynamics in the DRC were simulated using a stochastic agent-based model of transmission. Input parameter values for known properties, demographic variables, and interventions were fixed; infectivity was inferred from seropositivity profiles in survey data. Results: Our simulations of RCV introduction for the DRC demonstrate that an increase in CRS burden is unlikely. Continued endemic transmission is only plausible when routine immunization coverage is less than 40% and follow-up supplemental immunization activities have poor coverage for decades. Conclusion: Increased vaccination coverage tends to increase the annual variability of CRS burden. Simulations examining low vaccination coverage and high mean CRS burden are outbreak prone, with multiple years of reduced burden followed by acute outbreaks. These outcomes contrast simulations with no vaccination coverage and high mean CRS burden, which have more consistent burden from year to year.