Seasonal Influenza Vaccination Programs in the Americas: A Platform for Sustainable Life-Course Immunization and Its Role for Pandemic Preparedness and Response.

Vaccination is one of the most effective measures to prevent influenza illness and its complications. Since the 1980s, countries and territories in the Americas have progressively implemented influenza vaccination operations in high-risk priority groups-such as older adults, pregnant persons, persons with comorbidities and health workers. In this review, we present the history and progress of the seasonal influenza program in the Americas, how the program contributed to the efficient and timely roll-out of the COVID-19 vaccines during the pandemic, and how the program can be used to promote immunization operations across the life span for existing and future vaccines.

Progress Toward Elimination of Mother-to-Child Transmission of Hepatitis B Virus - Region of the Americas, 2012-2022.

In 2022, an estimated 5 million persons in the World Health Organization Region of the Americas (AMR) were living with chronic hepatitis B virus (HBV) infection, the leading cause of hepatocellular carcinoma and cirrhosis worldwide. Most chronic infections are acquired through mother-to-child transmission (MTCT) or horizontal transmission during childhood and are preventable with hepatitis B vaccination, including a birth dose (HepB-BD), followed by 2-3 additional doses (HepB3) in infancy. The Pan American Health Organization (PAHO) Elimination of MTCT of HBV infection strategy is intended to reduce chronic HBV infection (measured by hepatitis B surface antigen [HBsAg] seroprevalence) to ≤0.

The Impact of the Coronavirus Pandemic on Vaccination Coverage in Latin America and the Caribbean.

Background: Routine vaccination coverage in Latin America and the Caribbean declined prior to and during the coronavirus pandemic. We assessed the pandemic's impact on national coverage levels and analyzed whether financial and inequality indicators, immunization policies, and pandemic policies were associated with changes in national and regional coverage levels.

Methodology: We compared first- and third-dose coverage of diphtheria-pertussis-tetanus-containing vaccine (DTPcv) with predicted coverages using time series forecast modeling for 39 LAC countries and territories.

Maintaining the Region of the Americas free of polio: best practices for incident management support teams.

The Pan American Health Organization (PAHO) and its Member States have been leading the efforts to eradicate wild poliovirus in the Region of Americas since smallpox's successful elimination in 1971. The region became the first to be certified free of wild poliovirus in 1994. However, in July 2022, an unvaccinated patient with no recent travel history was diagnosed with poliomyelitis in the United States of America.

Description of maternal and neonatal adverse events in pregnant people immunised with COVID-19 vaccines during pregnancy in the CLAP NETWORK of sentinel sites. Nested case-control analysis of the immunization-associated risk: A study protocol.

Introduction: COVID-19 is associated with higher morbimortality in pregnant people compared with non-pregnant people. At present, the benefits of maternal immunisation are considered to outweigh the risks, and therefore, vaccination is recommended during pregnancy. However, additional information is needed on the safety of the vaccines in this population.

Understanding COVID-19 Vaccine Acceptance among Latin American Health Workers: Implications for Designing Interventions.

Health workers (HWs) have a key role in promoting vaccine acceptance. This study draws on the Behavioral and Social Drivers of Vaccination (BeSD) model and our team's investigation of vaccine hesitancy in a sample of 1197 HWs across 14 Caribbean countries in 2021. We conducted a cross-sectional Internet survey of 6718 HWs across 16 countries in Latin America in spring 2022, after the COVID-19 vaccine had recently become widely available in the region.

Systematic review on reducing missed opportunities for vaccinations in Latin America.

Objectives: To estimate the prevalence of missed opportunities for vaccination (MOV) in Latin America and the effect of interventions targeting health systems, health workers, patients, and communities on MOV.

Methods: Searches were conducted in MEDLINE, EMBASE, CINAHL, and LILACS electronic databases and relevant organizations were contacted, including the Pan American Health Organization (PAHO), to identify studies meeting eligibility criteria. A pair of reviewers identified 27 randomized and non-randomized studies quantifying the effectiveness of any intervention for reducing MOV and 5 studies assessing the rate of MOV in Latin America.

Promoting immunization equity in Latin America and the Caribbean: Case studies, lessons learned, and their implication for COVID-19 vaccine equity.

In 2020, the World Health Organization launched the Immunization Agenda 2030: A Global Strategy to Leave No One Behind, which prioritizes high equitable immunization coverage at the national level and in all districts. Achieving high and homogenous immunization coverage, which is all the more important within the current context of the COVID-19 pandemic and vaccine rollout, requires the strengthening of existing immunization activities and innovative approach to immunization promotion. This research applied a descriptive case study methodology to document the implementation of strategic multi-level alliances to promote equitable immunization access and demand in Colombia, Guyana, and Sucre, Bolivia.

Concerns, attitudes, and intended practices of Caribbean healthcare workers concerning COVID-19 vaccination: A cross-sectional study.

Background: The Caribbean has a long history of being a global leader in immunization, and one factor contributing to this success has been the commitment of healthcare workers in promoting the benefits of vaccines. Healthcare workers play a critical role in building trust between the public and the immunization program and are generally cited as the most trusted source of information on vaccination. Healthcare workers themselves, therefore, must be confident in vaccination as a public health good and able to transmit this confidence to those who trust them.

Using Household Surveys to Assess Missed Opportunities for Simultaneous Vaccination: Longitudinal Examples from Colombia and Nigeria.

One important strategy to increase vaccination coverage is to minimize missed opportunities for vaccination. Missed opportunities for simultaneous vaccination (MOSV) occur when a child receives one or more vaccines but not all those for which they are eligible at a given visit. Household surveys that record children's vaccination dates can be used to quantify occurrence of MOSVs and their impact on achievable vaccination coverage.

Estimating global and regional disruptions to routine childhood vaccine coverage during the COVID-19 pandemic in 2020: a modelling study.

Background: The COVID-19 pandemic and efforts to reduce SARS-CoV-2 transmission substantially affected health services worldwide. To better understand the impact of the pandemic on childhood routine immunisation, we estimated disruptions in vaccine coverage associated with the pandemic in 2020, globally and by Global Burden of Disease (GBD) super-region.

Methods: For this analysis we used a two-step hierarchical random spline modelling approach to estimate global and regional disruptions to routine immunisation using administrative data and reports from electronic immunisation systems, with mobility data as a model input.

Monitoring progress of maternal and neonatal immunization in Latin America and the Caribbean.

Introduction: The Americas committed to strengthening maternal and neonatal immunization (MNI) through the Pan American Health Organization (PAHO) Regional Immunization Action Plan (RIAP) 2016-20. We describe the progress toward RIAP MNI-related targets and those related to improvement of data quality and information systems; analyze national MNI policies and vaccination coverages; and identify enablers and challenges of monitoring and reporting MNI vaccination coverage in Latin America and the Caribbean (LAC).

Methodology: Descriptive study of national MNI policies, vaccination coverage, and information systems.

HPV vaccination introduction worldwide and WHO and UNICEF estimates of national HPV immunization coverage 2010-2019.

WHO/UNICEF estimates for HPV vaccination coverage from 2010 to 2019 are analyzed against the backdrop of the 90% coverage target for HPV vaccination by 2030 set in the recently approved global strategy for cervical cancer elimination as a public health problem. As of June 2020, 107 (55%) of the 194 WHO Member States have introduced HPV vaccination. The Americas and Europe are by far the WHO regions with the most introductions, 85% and 77% of their countries having already introduced respectively.

Assessing electronic immunization registries: the Pan American Health Organization experience.

Objective: To develop a methodology to assess electronic immunization registries (EIRs) in low- and middle-income countries (LMICs) in Latin America and the Caribbean.

Methods: A team from the Immunization Unit at the Pan American Health Organization (PAHO) reviewed existing methodologies to evaluate health information systems, particularly the Performance of Routine Information System Management (PRISM) framework and methodologies used to assess information systems. In 2014, the PAHO team convened a small working group to develop an evaluation approach to be added to the existing World Health Organization immunization data quality self-assessment (DQS) tool.

Improving immunization data quality in Peru and Mexico: Two case studies highlighting challenges and lessons learned.

Introduction: The Global Vaccine Action Plan and the Regional Immunization Action Plan of the Americas call for countries to improve immunization data quality. Immunization information systems, particularly electronic immunization registries (EIRs), can help to facilitate program management and increase coverage. However, little is known about efforts to develop and implement such systems in low- and middle-income countries.

Progress in vaccination towards hepatitis B control and elimination in the Region of the Americas.

Background: Over recent decades, the Region of the Americas has made significant progress towards hepatitis B elimination. We summarize the countries/territories' efforts in introducing and implementing hepatitis B (HB) vaccination and in evaluating its impact on HB virus seroprevalence.

Methods: We collected information about HB vaccination schedules, coverage estimates, and year of vaccine introduction from countries/territories reporting to the Pan American Health Organization/World Health Organization (PAHO/WHO) through the WHO/UNICEF Joint Reporting Form on Immunization.

Missed Opportunities for Vaccination in the Dominican Republic: Results of an Operational Investigation.

. Despite the success of the Dominican Republic's National Immunization Program, homogenous vaccine coverage has not been achieved. In October 2012, the country implemented a study on missed opportunities for vaccination (MOVs) in children aged <5 years.

Lessons learned from the development of a new methodology to assess missed opportunities for vaccination in Latin America and the Caribbean.

The Pan American Health Organization recently developed a practical guide for evaluating missed opportunities for vaccination among children aged <5 years. A missed opportunity occurs when an individual eligible for vaccination has contact with a health facility and does not receive a needed vaccine, despite having no contraindications. In this article, we discuss the strengths and limitations of this new methodology and present lessons learned from recent studies on undervaccination in Latin America.

Understanding the main barriers to immunization in Colombia to better tailor communication strategies.

Background: The Expanded Program on Immunization (EPI) in Colombia has made great advances since its inception in 1979; however, by 2010 vaccination coverage rates had been declining. In 2010, the EPI commissioned a nationwide study on practices on immunization, attitudes and knowledge, perceived service quality, and barriers to childhood immunization in order to tailor EPI communication strategies.

Methods: Colombia's 32 geographical departments were divided into 10 regions.

From the parents' perspective: a user-satisfaction survey of immunization services in Guatemala.

Background: Immunization coverage levels in Guatemala have increased over the last two decades, but national targets of ≥95% have yet to be reached. To determine factors related to undervaccination, Guatemala's National Immunization Program conducted a user-satisfaction survey of parents and guardians of children aged 0-5 years. Variables evaluated included parental immunization attitudes, preferences, and practices; the impact of immunization campaigns and marketing strategies; and factors inhibiting immunization.

How cost effective is universal varicella vaccination in developing countries? A case-study from Colombia.

Objective: Varicella vaccination has not been introduced worldwide, especially in developing countries. The present study assesses the potential epidemiological and economic impact of one-dose and two-dose varicella vaccination schemes in Colombia, a south American upper middle-income country.

Methods: A decision-tree based model was developed.

Cost-effectiveness of pneumococcal conjugate vaccines of 7, 10, and 13 valences in Colombian children.

Background: Currently there are three pneumococcal conjugate vaccines with different coverage of serotypes for use in children under one year. We evaluate the cost-effectiveness of the introduction of pneumococcal conjugate vaccines of 7, 10, and 13 valences in the Colombian EPI.

Methods: A Markov model, which followed a cohort of children under one year to life expectancy, was developed.