Public Health Responses During Measles Outbreaks in Elimination Settings: Strategies and Challenges

In late September 2016, the Americas eliminated endemic transmission of measles virus. Several other countries have also verified measles elimination, and countries in all six World Health Organization (WHO) regions have adopted measles elimination goals. This review highlights the public health strategies used to limit measles spread in elimination settings, discussing the evidence base for the strategies, the challenges faced when applying them, and the lessons learned on how to successfully implement them. This summary focuses on the communication-related elements of those strategies.

As is explained here, the work of maintaining measles control does not stop once measles elimination is verified. Public health systems need to sustain physician awareness, high immunisation coverage, and elimination-standard surveillance in the face of almost no disease, as long as measles is still endemic anywhere in the world. When no endemic measles virus is circulating, it can be challenging to convince parents to get their children vaccinated and to prompt clinicians to test febrile rash illnesses for measles. It can also be difficult to maintain laboratory proficiency and sustain resources for an immunisation programme. In this context, sharing the experience of using different containment strategies in countries that have eliminated measles for some time is increasingly relevant to a greater number of countries.

Outbreak response strategies discussed in the article that have a communication component include:

• Assembly of an outbreak control committee - Local personnel who are adequately trained in reporting and investigating outbreaks and are familiar with the affected population, or who have established relationships with leaders in the community, can contribute greatly to the decision-making process. As with all emergency response teams, establishing and maintaining partnerships among members of the committee through routine training and emergency planning activities can help the committee work effectively once an outbreak occurs.
• Communication with the public and other health authorities to raise awareness of the risk of measles - For example, when exposures occur in large venues (such as restaurants, malls, or cinemas) or on public transport, the number exposed and the level of risk is uncertain. Thus, in lieu of individual contact tracing, informing the public about a potential exposure may improve case-finding. The public can be updated on the outbreak status and alerted of potential exposures in a variety of ways, including press briefings, media releases, notices on health department websites, forums involving community leaders, flyers posted at exposure sites, advertisements, or social media posts. Public communication should aim to provide consistent and clear information that is timely and frequent.
• Education of cases or their caregivers about the mode of transmission, infectious period, and measures to minimise the spread of measles - Preferably, this advice is given as printed materials (fact sheets are often developed for this purpose). Exposed persons are counseled to be watchful for measles compatible symptoms, and they are given steps to follow if illness develops. More generally, measles outbreaks serve as a reminder of the risk of not vaccinating, and they can be used by health authorities to promote vaccination and increase coverage.

Containment strategies covered include: isolation of measles cases while infectious; exclusion and quarantining of individuals without evidence of immunity; vaccination of susceptible individuals ("delivering outbreak response strategies through culturally suitable approaches (e.g., involving community and spiritual leaders, interpreters, and local public health advisors) is key for their success"); use of immunoglobulin to prevent measles in exposed susceptible high-risk persons; and maintaining laboratory proficiency for confirmation of measles.

In conclusion: "The only truly foolproof means to limit the extent of measles outbreaks and the contingent morbidity, mortality, and economic burden posed by measles importations in all countries is to maintain, via high immunization coverage, robust herd immunity throughout the population. It is thus essential to interrogate every outbreak and patterns of outbreaks, so as to pinpoint communities with geographical or shared socio-cultural features that are consistently missing out on the benefits of measles vaccination, or to identify settings allowing a greater opportunity for measles transmission. Targeting vaccination strategies to fill these immunity gaps can be a valuable legacy of thorough outbreak investigations."