Assessing the Effectiveness and Cost-Benefit of Test-and-Vaccinate Policy for Supplementary Vaccination against Rubella with Limited Doses.

Masaya Saito,Ryo Kinoshita,Keisuke Ejima,Hiroshi Nishiura

doi:10.3390/ijerph15040572

Abstract

Elevating herd immunity level against rubella is essential to prevent congenital rubella syndrome (CRS). Insufficient vaccination coverage left susceptible pockets among adults in Japan, and the outbreak of rubella from 2012 to 2013 resulted in 45 observed CRS cases. Given a limited stock of rubella-containing vaccine (RCV) available, the Japanese government recommended healthcare providers to prioritize vaccination to those confirmed with low level of immunity, or to those likely to transmit to pregnant women. Although a test-and-vaccinate policy could potentially help reduce the use of the limited stockpile of vaccines, by selectively elevating herd immunity, the cost of serological testing is generally high and comparable to the vaccine itself. Here, we aimed to examine whether random vaccination would be more cost-beneficial than the test-and-vaccinate strategy. A mathematical model was employed to evaluate the vaccination policy implemented in 2012–2013, quantifying the benefit-to-cost ratio to achieve herd immunity. The modelling exercise demonstrated that, while the test-and-vaccinate strategy can efficiently achieve herd immunity when stockpiles of RCV are limited, random vaccination would be a more cost-beneficial strategy. As long as the herd immunity acts as the goal of vaccination, our findings apply to future supplementary immunization strategy.

Highlights

Rubella, caused by infection with rubella virus, is generally a mild and self-limiting disease, but infection during pregnancy, especially during the first trimester, can result in complications in the fetus, known as the congenital rubella syndrome (CRS) [1]
When the risk of rubella infection is elevated to women at childbearing age, vaccination and its insufficient herd immunity can controversially increase the risk of CRS in the fetus [2,3]
While vaccination policy is judged by various aspects, including laboratory test performance and adverse events of vaccination, we focus on the supplementary vaccination policy which is implemented as a reaction to the re-emergence of rubella

Summary

Introduction

Rubella, caused by infection with rubella virus, is generally a mild and self-limiting disease, but infection during pregnancy, especially during the first trimester, can result in complications in the fetus, known as the congenital rubella syndrome (CRS) [1]. The pitfall of mass vaccination strategies against rubella is that, when the population is not sufficiently immunized to prevent a major epidemic, vaccination allows a push forward of the age at infection. When the risk of rubella infection is elevated to women at childbearing age, vaccination and its insufficient herd immunity can controversially increase the risk of CRS in the fetus [2,3]. Sufficiently elevating herd immunity level has been recognized as an essential step to prevent rubella and CRS, and to medically and economically justify the implementation of mass vaccination [4,5]. Public Health 2018, 15, 572; doi:10.3390/ijerph15040572 www.mdpi.com/journal/ijerph

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