Influenza vaccination in the Americas: Progress and challenges after the 2009 A(H1N1) influenza pandemic.

BACKGROUND: There has been considerable uptake of seasonal influenza vaccines in the Americas compared to other regions. We describe the current influenza vaccination target groups, recent progress in vaccine uptake and in generating evidence on influenza seasonality and vaccine effectiveness for immunization programs. We also discuss persistent challenges, 5 years after the A(H1N1) 2009 influenza pandemic. METHODS: We compiled and summarized data annually reported by countries to the Pan American Health Organization/World Health Organization (PAHO/WHO) through the WHO/UNICEF joint report form on immunization, information obtained through PAHO's Revolving Fund for Vaccine Procurement and communications with managers of national Expanded Programs on Immunization (EPI). RESULTS: Since 2008, 25 countries/territories in the Americas have introduced new target groups for vaccination or expanded the age ranges of existing target groups. As of 2014, 40 (89%) out of 45 countries/territories have policies established for seasonal influenza vaccination. Currently, 29 (64%) countries/territories target pregnant women for vaccination, the highest priority group according to WHO´s Stategic Advisory Group of Experts and PAHO/WHO's Technical Advisory Group on Vaccine-preventable Diseases, compared to only 7 (16%) in 2008. Among 23 countries reporting coverage data, on average, 75% of adults ≥60 years, 45% of children aged 6-23 months, 32% of children aged 5-2 years, 59% of pregnant women, 78% of healthcare workers, and 90% of individuals with chronic conditions were vaccinated during the 2013-14 Northern Hemisphere or 2014 Southern Hemisphere influenza vaccination activities. Difficulties however persist in the estimation of vaccination coverage, especially for pregnant women and persons with chronic conditions. Since 2007, 6 tropical countries have changed their vaccine formulation from the Northern to the Southern Hemisphere formulation and the timing of their campaigns to April-May following the review of national evidence. LAC countries have also established an official network dedicated to evaluating influenza vaccines effectiveness and impact. CONCLUSION: Following the A(H1N1)2009 influenza pandemic, countries of the Americas have continued their efforts to sustain or increase seasonal influenza vaccine uptake among high risk groups, especially among pregnant women. Countries also continued strengthening influenza surveillance, immunization platforms and information systems, indirectly improving preparedness for future pandemics. Influenza vaccination is particularly challenging compared to other vaccines included in EPI schedules, due to the need for annual, optimally timed vaccination, the wide spectrum of target groups, and the limitations of the available vaccines. Countries should continue to monitor influenza vaccination coverage, generate evidence for vaccination programs and implement social communication strategies addressing existing gaps.

Pandemic influenza vaccination: lessons learned from Latin America and the Caribbean.

In April 2009, the World Health Organization (WHO) reported the emergence of a new influenza (H1N1) virus which led to the first pandemic declaration of the 21st century. Most countries in Latin America and the Caribbean (LAC) had a national preparedness plan in place at this time; however, the vaccination component of such plans was largely undeveloped. Nevertheless, countries were able to capitalize on the infrastructure of their immunization programs and widespread experience utilizing the seasonal influenza vaccine to prepare rapidly, developing H1N1 vaccination plans targeting individuals with chronic disease, pregnant women and health care workers, among others. In LAC vaccine was acquired through three mechanisms: the Pan American Health Organization's Revolving Fund, direct manufacturer purchase, and WHO donations. Vaccine access was not equitable both in quantity of vaccine available and timeless of vaccine availability. As of December 2010, an estimated 145 million doses had been administered in LAC. Despite high regional coverage, there were large variations in coverage at the national level; pregnant women had the lowest coverage, despite their high risk for morbidity and mortality. The number of severe adverse events reported in LAC was similar to those expected with the seasonal influenza vaccine. Risk communication was one of the key challenges countries faced, mainly due to concerns and misinformation spread regarding vaccine safety. Countries and the international community need to learn from the experiences gained during H1N1 vaccination in order to be better prepared for the next pandemic.

The evolution of Vaccination Week in the Americas / La evolución de la Semana de Vacunación en las Américas / Evolução da Semana de Vacinação nas Américas

ABSTRACT This report covers the background and evolution of Vaccination Week in the Americas (VWA), an initiative that started as a coordinated response to a 2002 measles outbreak in Colombia and Venezuela, and evolved into the model for other regions and World Immunization Week (WIW). VWA focuses on the work of national immunization programs, with special efforts to reach the unreached. This paper offers examples of how countries have leveraged VWA to implement a diverse array of vaccination activities, strengthening overall health services by integrating with other preventive health interventions, and bolstering "Pan-Americanism" and health diplomacy. The opportunities offered by this global initiative were clearly demonstrated in April 2016 when the successful global switch from the trivalent oral polio vaccine to the bivalent vaccine was synchronized with WIW. Going forward, VWA and WIW can help close the gaps in access to immunization and other health services, contributing to achieve universal health coverage.(AU)

RESUMEN Este informe incluye los antecedentes y la evolución de la Semana de Vacunación en las Américas, una iniciativa que comenzó como una respuesta coordinada a un brote de sarampión en Colombia y Venezuela en el 2002, y evolucionó hasta convertirse en modelo para otras regiones y para la Semana Mundial de la Inmunización. La Semana de Vacunación en las Américas se centra en el trabajo de los programas nacionales de inmunización, con esfuerzos especiales para llegar a las personas que todavía no estén cubiertas. En el presente trabajo se dan ejemplos de cómo los países han aprovechado la Semana de Vacunación para realizar diversas actividades relacionadas con la vacunación, fortalecer los servicios de salud en general mediante la integración con otras intervenciones preventivas y fomentar el "panamericanismo" y la diplomacia en torno a la salud. Las oportunidades que ofrece esta iniciativa mundial quedaron claramente evidenciadas en abril del 2016 con el éxito obtenido en la sustitución de la vacuna oral trivalente contra la poliomielitis por la vacuna bivalente, sincronizada con la Semana Mundial de la Inmunización. En el futuro, la Semana de Vacunación en las Américas y la Semana Mundial de Inmunización pueden ayudar a subsanar la brecha en el acceso a la inmunización y otros servicios de salud, y contribui(AU)

RESUMO Este artigo narra os antecedentes e a evolução da Semana de Vacinação nas Américas (SVA), uma iniciativa que nasceu da resposta coordenada ao surto de sarampo na Colômbia e na Venezuela em 2002 e evoluiu como um modelo para as outras regiões e para a Semana Mundial da Imunização. A SVA põe ênfase no trabalho dos programas nacionais de vacinação e, principalmente, nos esforços para se alcançar quem ainda está inalcançado. São ilustrados exemplos de como os países têm aproveitado a SVA para implementar várias atividades de vacinação, fortalecendo os serviços de saúde em geral ao integrá-la a outras intervenções preventivas e reforçando o pan-americanismo e a diplomacia da saúde. As oportunidades criadas por esta iniciativa global ficaram bem evidentes em abril de 2016 com a bem-sucedida transição em nível mundial da vacina oral contra poliomielite trivalente à bivalente, em sincronia com a Semana Mundial da Imunização. Prosseguindo adiante, a SVA e a Semana Mundial da Imunização podem contribuir para sanar as lacunas no acesso à imunização e a outros serviços de saúde e alcançar a cobertura universal de saúde.(AU)