Vaccination Week in the Americas: An Ongoing Initiative to Strengthen and Sustain Measles and Rubella Elimination in the Region

Introduction
Vaccination Week in the Americas (VWA) is the Americas' yearly initiative for the promotion of the regional immunisation programme and the closure of the most urgent immunity gaps. It is designed to serve as a coordinated and flexible platform for countries to offer vaccines and promote the benefits of immunisation to health workers and the public. Over the years, countries have taken advantage of this event to complement the operations of the routine immunisation programme or to launch mass vaccination campaigns and mop-up operations. In its 22-year history, more than 1.15 billion people have been vaccinated under the framework of VWA. Of note, this figure includes the administration of at least 78.8 million doses of measles and rubella-containing vaccine (MMR or MR), of which more than 40.5 million were adult doses. This review documents the contributions of the VWA to achieve and sustain the elimination of measles, rubella, and congenital rubella syndrome (CRS) in the Americas.

History of the Vaccination Week in the Americas
Celebrated each April in the Americas since 2002, VWA was first created in response to an outbreak of measles along the border between Venezuela and Colombia. In September 2003, during Pan American Health Organization (PAHO)'s 44th Directing Council, health ministers endorsed Resolution CD44.R1 "Sustaining Immunization Programs-Elimination of Rubella and Congenital Rubella Syndrome (CRS)", which included language supporting "the implementation of an annual hemispheric Vaccination Week ...targeting high-risk population groups and underserved areas." This resolution was significant because it provided the political mandate for countries' participation in VWA in the years to come. Also, the VWA served as an inspiration for the creation of World Immunization Week (WIW) by the World Health Organization (WHO). Following the example of the Americas, other WHO regions created their own regional vaccination weeks (EURO in 2005; EMRO in 2010; AFRO in 2011; WPRO in 2011; and SEARO in 2012).

Each year, PAHO develops a regional VWA communication campaign. Materials include a slogan that reflects current events and priorities. PAHO creates digital and print materials (including posters, banners, stickers, gifs, videos, and images), public service announcement (PSA) infographics, and a social media package with content tailored for a variety of platforms. Countries can adapt these materials to meet the goals and targets of their own VWA campaign and ensure that all images and messages reflect the ethnic and linguistic composition of their populations. Over the years, many countries adapted these materials and slogans to promote the mass vaccination campaign they implement against measles and rubella. For example, in 2014 and 2018 - both FIFA World Cup years - the VWA regional communication campaign themes used soccer slogans and graphics to focus on strengthening surveillance operations and vaccination activities to prevent measles and rubella outbreaks.

Community engagement is another critical element of VWA communication campaigns. Over the years, countries developed multiple approaches to engage with different audiences at the local level in order to promote vaccination against measles/rubella. For example, collaboration with church leaders has allowed the VWA to promote key vaccination messages among their congregations. In other cases, high-level health professionals or political leaders have been invited to speak about vaccination opportunities during religious services. Often, churches serve as the location for health fairs and MMR or MR vaccination during the VWA week.

Lessons learned
Political priority
The main lesson learned from the VWA is the importance of a periodic, well-coordinated and flexible opportunity for governments and heads of state to address the importance of vaccines and vaccination operations, regardless of other political priorities or events. Another lesson learned is the convenience of the VWA as a well-established platform to facilitate and accelerate the implementation of region-wide public health interventions. As with the trivalent-bivalent oral polio vaccine (OPV) switch in 2016 and the introduction of the COVID-19 vaccines in 2021, the VWA can ease these moments of transition by presenting them within a familiar and reliable framework to both the health workforce and the public.

Vaccination operations
The VWA provides a platform to implement synchronised and massive vaccination campaigns, thus holding the potential to increase population immunity levels quickly. Flexibility is another attribute of the VWA platform. Countries set their own vaccination goals, so the initiative becomes an annual opportunity to advance national public health priorities. At the same time, by maintaining measles and rubella elimination as a regional target, PAHO provides ongoing guidance and support to countries and partners to achieve this common goal, while allowing space for Member States to implement the vaccination strategies that work best for their context.

Communications and community engagement
In the area of communications, there are two main lessons learned. The first is the importance of allowing countries to adapt the VWA communications materials. Countries have multiple options to select the images that best reflect their populations. Also, all information materials developed by the regional level are designed so that countries can easily replace region-level data with their own national and local information and can further tailor the materials to speak to their own priorities. The second lesson learned is to use the VWA platform to increase the public's risk perception of measles and rubella disease, while decreasing its risk perception associated with the safety and effectiveness of MR vaccination. The VWA provides multiple opportunities for public health experts to promote these points, as well as to meaningfully engage with health workers and the public on MR vaccination, address doubts and provide reliable and updated information.

Conclusions
Since 2002, the countries and territories of the Americas have used the VWA to renew their political and financial commitment to the regional immunisation programme, advance in the elimination of vaccine-preventable diseases - including measles and rubella - and remind the public of the benefits of vaccines for the health and wellbeing of all communities. Its consistent implementation during the last week of April allows countries to join this yearly appointment through coordinated operations and messages and offers the public a familiar interface with the national vaccination programme. In its next iterations, the VWA will continue to support the PAHO Elimination Initiative while it contributes to closing the most urgent immunity gaps.