Chapter 10. Laboratory support for the verification of elimination of measles and rubella

Mick Mulders

Overview

In the Global Measles and Rubella Strategic Plan, 2012–2020 [1], the target date of 2020 was established for the elimination of measles and rubella in at least five of the six WHO Regions. Following review of the draft documents by the Strategic Advisory Group of Experts on Immunization (SAGE), the working group on measles and rubella prepared revised guidance to monitor the progress toward the goal of elimination and crafted a framework for countries and regions to verify the elimination of measles and rubella.

The document, Framework for verifying the elimination of measles and rubella, was developed for settings in which efforts to achieve the goal of the interruption of both measles and rubella are underway [2]. The working group drew upon the experience gained in all WHO regions to provide a standardised process that can be followed to provide the necessary data required for verification of elimination. Three essential criteria were identified, based on the methods followed to verify elimination in the Region of the Americas:

Essential criteria: verification of elimination

  1. Documentation of the interruption of endemic measles, or rubella, virus transmission for a period of at least 36 months from the last known endemic case.
  2. The presence of a high-quality surveillance system that is sensitive and specific enough to detect imported and import-related cases.
  3. Genotyping evidence that supports the interruption of endemic transmission.
The WHO framework document provides specific data and surveillance information necessary to assess the adequacy of actions taken to support each line of evidence. By providing a comprehensive approach to the verification process, a consistent assessment will be utilized by all Regions. The process for determining verification is intended to harmonize activities of different WHO Regions to the greatest extent possible within constraints of resources and variations in national programmes.

The regional verification commissions should consider five lines of evidence to evaluate whether a country or the entire Region has achieved elimination. The five lines of evidence incorporate the three essential criteria listed above as well as other supporting information to assess both past programme performance and future capacity to sustain elimination.

Five lines of evidence

  1. A detailed description of the epidemiology of measles and rubella since the introduction of measles and rubella vaccine in the national immunization programme.
  2. Population immunity presented as a birth cohort analysis with the addition of evidence related to any marginalized and migrant groups.
  3. Quality of epidemiological and laboratory surveillance systems for measles and rubella.
  4. Sustainability of the national immunization programme including resources for mass campaigns, where appropriate, in order to sustain elimination
  5. Genotyping evidence that measles and rubella virus transmission is interrupted.
Laboratory testing, preparation of summaries, maintenance of records, and data analysis generated by laboratories in the GMRLN are vital for the documentation required for verification. Similarly, activities such as participation in quality assurance and accreditation are of paramount importance to ensure and demonstrate high quality, laboratory-based surveillance.

This chapter describes the data and supporting evidence required for monitoring progress towards, and eventual elimination of, measles and rubella, with a particular focus on the requirements that are directly related to laboratory activities. The documentation for the required information is covered in detail in Chapter 11. Data management and reporting of laboratory results.