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.
Background: Seasonal influenza is a viral disease whose annual epidemics are estimated to cause three to five million cases of severe illness and 250,000 to 500,000 deaths worldwide. Vaccination is the main strategy for primary prevention.
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.
Vaccination Week in the Americas (VWA) is an initiative of the countries and territories of the Americas that works to advance equity and access to vaccination. The initiative focuses on reaching populations with limited access to regular health services and promotes solidarity among countries. As the Expanded Program on Immunization is one of the world’s best-established health programs, integrating other interventions with immunization services has been highly promoted. Using data available from the Pan American Health Organization, we explored the extent of integration of other interventions with immunization in Latin American and Caribbean (LAC) countries as part of VWA. At least 14 countries or territories have integrated other interventions with immunization during VWA. The most common integrated intervention is vitamin A supplementation, followed by deworming. However, a variety of other interventions have been integrated, such as educational activities, supplementation with vitamins and minerals, and provision of health services. Data on coverage of integrated interventions are limited. Integration of other interventions with immunization in LAC countries is widespread, and its impact and lessons learned merit further examination.
As part of the vaccination activities against influenza A[H1N1]pdm vaccine in 2009-2010, countries in Latin American and the Caribbean (LAC) implemented surveillance of events supposedly attributable to vaccines and immunization (ESAVI). We describe the serious ESAVI reported in LAC in order to further document the safety profile of this vaccine and highlight lessons learned. We reviewed data from serious H1N1 ESAVI cases from LAC countries reported to the Pan American Health Organization/World Health Organization. We estimated serious ESAVI rates by age and target group, as well as by clinical diagnosis, and completed descriptive analyses of final outcomes and classifications given in country. A total of 1000 serious ESAVI were reported by 18 of the 29 LAC countries that vaccinated against A[H1N1]pdm. The overall reporting rate in LAC was 6.91 serious ESAVI per million doses, with country reporting rates ranging from 0.77 to 64.68 per million doses. Rates were higher among pregnant women (16.25 per million doses) when compared to health care workers (13.54 per million doses) and individuals with chronic disease (4.03 per million doses). The top three most frequent diagnoses were febrile seizures (12.0%), Guillain-Barré Syndrome (10.5%) and acute pneumonia (8.0%). Almost half (49.1%) of the serious ESAVI were reported among children aged <18 years of age; within this group, the highest proportion of cases was reported among those aged <2 years (53.1%). Of all serious ESAVI reported, 37.8% were classified as coincidental, 35.3% as related to vaccine components, 26.4% as non-conclusive and 0.5% as a programmatic error. This regional overview of A[H1N1]pdm vaccine safety data in LAC estimated the rate of serious ESAVI at lower levels than other studies. However, the ESAVI diagnosis distribution is comparable to the published literature. Lessons learned can be applied in the response to future pandemics.
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 .
BackgroundVaccination Week in the Americas (VWA) is an annual initiative in countries and territories of the Americas every April to highlight the work of national expanded programs on immunization (EPI) and increase access to vaccination services for high-risk population groups. In 2011, as part of VWA, Venezuela targeted children aged less than 6 years in 25 priority border municipalities using social mobilization to increase institution-based vaccination. Implementation of social communication activities was decentralized to the local level. We conducted a survey in one border municipality of Venezuela to evaluate the outcome of VWA 2011 and provide a snapshot of the overall performance of the routine EPI at that level.MethodsWe conducted a coverage survey, using stratified cluster sampling, in the Venezuelan municipality of Bolivar (bordering Colombia) in August 2011. We collected information for children aged <6 years through caregiver interviews and transcription of vaccination card data. We estimated each child’s eligibility to receive a specific vaccine dose during VWA 2011 and whether or not they were actually vaccinated during VWA activities. We also estimated baseline vaccination coverage, timeliness and 95% confidence intervals (CI), and used chi-square tests to compare coverage across age cohorts, taking into account the sampling design.ResultsWe surveyed 839 children from 698 households; 93% of children had a vaccination card. Among households surveyed, 216 (31%) caregivers reported having heard about a vaccination activity during April or May 2011. Of the 528 children eligible to receive a vaccine during VWA, 24% received at least one dose, while 13% received all doses due. Overall, baseline coverage with routine vaccines, as measured by the survey, was >85%, with a few exceptions.ConclusionLow levels of VWA awareness among caregivers probably contributed to the limited vaccination of eligible children during the VWA activities in Bolivar in 2011. However, vaccine coverage for most EPI vaccines was high. Additionally, high vaccination card availability and high participation in VWA among those caregivers aware of it in 2011 suggest public trust in the EPI program in the municipality. Health authorities have used survey findings to inform changes to the routine EPI and better VWA implementation in subsequent years.
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