# Congenital Rubella Syndrome Does Not Increase with Introduction of Rubella-Containing Vaccine

## TL;DR

Rubella vaccination reduces disease burden, and while it may slightly increase risk in some high-transmission areas long-term, the benefits of vaccination outweigh the risks.

## Contribution

The study demonstrates that rubella vaccination reduces disease burden and identifies conditions under which future resurgence might occur.

## Key findings

- Introducing RCV reduces rubella transmission and disease burden for about 15 years.
- Increased disease burden is only possible more than a decade post-introduction in high-transmission contexts.
- Low transmission intensity is linked to greater burden reduction with vaccination.

## Abstract

Rubella infection is typically mild or asymptomatic except when infection occurs during pregnancy. Infection in early pregnancy can cause miscarriage, stillbirth, or congenital rubella syndrome. Only individuals that are still susceptible to rubella infection during child-bearing age are vulnerable to this burden. Rubella-containing vaccine (RCV) is safe and effective, providing life-long immunity. However, average age-at-infection increases with increasing vaccination coverage, which could potentially lead to increased disease burden if the absolute risk of infection during child-bearing age increases. The dynamics of rubella transmission were explored using EMOD, a software tool for building stochastic, agent-based infection models. Simulations of pre-vaccine, endemic transmission of rubella virus introduced RCV at varying levels of coverage to determine the expected future trajectories of disease burden. Introducing RCV reduces both rubella virus transmission and disease burden for a period of around 15 years. Increased disease burden is only possible more than a decade post-introduction, and only for contexts with persistently high transmission intensity. Low or declining rubella virus transmission intensity is associated with both greater burden without vaccination and greater burden reduction with vaccination. The risk of resurgent burden due to incomplete vaccination only exists for locations with persistently high infectivity, high connectivity, and high fertility. A trade-off between the risk of a small, future burden increase versus a large, immediate burden decrease strongly favors RCV introduction.