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. Sources of information included PAHO-World Health Organization (WHO) / UNICEF Joint Reporting Forms on immunization (JRF) 2013-2019, and other reports.

RESULTS

LAC has met two of three RIAP targets related to MNI (countries with universal hepatitis B birth dose introduction and elimination of maternal and neonatal tetanus) and is on track to meet the other (countries with vaccination of pregnant women). As of 2018, of the 49 countries and territories in LAC, 32 vaccinate pregnant women against influenza and 29 provide tetanus-containing vaccine. Twenty-five countries offer universal hepatitis B birth dose vaccine and 31 offer BCG vaccine. In 2018, regional influenza vaccine coverage among pregnant woman was 75%. Regional coverages for BCG and hepatitis B birth dose (<24 h) vaccines were 93% and 79%, respectively. Countries have exceeded RIAP targets related to the quality of vaccination coverage data and the establishment of electronic immunization registries (EIRs). Challenges in monitoring MNI coverage include estimation of denominators and difficulties disaggregating data by group (e.g., pregnant women versus other groups).

CONCLUSION

Despite progress in improving MNI in LAC, countries must further strengthen immunization monitoring systems and data quality to better report vaccination coverage among pregnant women and newborns. EIR and MNI information systems must be integrated, such that countries can use accurate data to design more timely and effective vaccination strategies.

HPV vaccine implementation and monitoring in Latin America

OBJECTIVE

To describe HPV vaccine program implementation, monitoring and evaluation experiences in Latin America.

MATERIALS AND METHODS

We reviewed published articles in peer-reviewed journals and reports from government web- sites, as well as the PAHO/WHO/UNICEF Joint Reporting form and the ICO/IARC HPV Information Centre database.

RESULTS

By December 2016, 13 countries/territories in Latin America (56%) have introduced HPV vaccines. The majority have done so in the past three years, targeting 10- 12 year old girls with a two dose schedule, through school programs. Vaccine coverage ranges from 30 to 87%. Safety monitoring is well established, but monitoring vaccine impact is not, and data are not available.

CONCLUSIONS

. Although Latin America is the most advanced developing region with HPV vaccine introduction, systems for its monitoring are weak and there is a paucity of consistently available coverage data for this vaccine. Challenges remain to introduce HPV vaccines in several countries, to achieve high coverage, and to strengthen monitoring, evaluation and reporting.

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. We obtained additional information regarding countries/territories vaccination recommendations and strategies through communications with Expanded Program on Immunization (EPI) managers and national immunization survey reports. We identified vaccine impact studies conducted and published in the Americas.

RESULTS

As of October 2016, all 51 countries/territories have included infant HB vaccination in their official immunization schedule. Twenty countries, whose populations represent over 90% of the Region's births, have included nationwide newborn HB vaccination. We estimated at 89% and 75%, the regional three-dose series and the birth dose HB vaccination coverage, respectively, for 2015. The impact evaluations of infant HB immunization programs in the Region have shown substantial reductions in HB surface antigen (HBsAg) seroprevalence.

CONCLUSION

The achievements of vaccination programs in the Americas suggest that the elimination of perinatal and early childhood HB transmission could be feasible in the short-term. Moreover, the data gathered indicate that the Region may have already achieved the 2020 WHO goal for HB control.

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.

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. Our findings should be useful to countries embarking on assessing the magnitude and the causes of missed opportunities for vaccination children experience at health facilities.

Electronic immunization registries in Latin America: progress and lessons learned

Most of the current vaccination coverage monitoring in Latin America relies on aggregated data. Improved monitoring has been shown to result in better coverage. Taking advantage of current information and communication technologies, the use of electronic immunization registries (EIRs) can facilitate coverage monitoring in terms of particularity (at the level of the individual), timeliness, and accuracy. Countries in Latin America are rapidly developing and implementing national EIRs to improve the monitoring of immunization coverage. These countries are using a variety of approaches toward system conception and development; integration with larger health information systems; different modalities for data collection, entry, and transmission; and other key features. Some countries are exploring linkages with mHealth (mobile health) for data collection and for automated recall/reminders. Evaluating EIRs and sharing experiences are important to streamlining and improving national EIR development, implementation, and use, and to ensuring its sustainability.

Temporal trends in diarrhea-related hospitalizations and deaths in children under age 5 before and after the introduction of the rotavirus vaccine in four Latin American countries

INTRODUCTION

Rotavirus infection mainly affects children under 5 years of age and causes 453,000 deaths annually throughout the world. Several countries in Latin America have introduced the rotavirus vaccine and the majority have epidemiological data to measure impact following vaccine introduction.

OBJECTIVE

To assess the impact of rotavirus immunization on the number of all-cause diarrhea-related deaths and hospitalizations in children under 1 and 5 years of age in Bolivia, El Salvador, Honduras and Venezuela.

METHODS

Interrupted time-series analyzed with the integral method and the projection method to evaluate the pre and post-vaccine introduction trend in diarrheal disease compared to Argentina as the control country. The analysis period was from 2002 to 2010, including 2 to 4 post-vaccine years depending on the country. Information sources included records from PAHO, the Ministry of Health, public hospitals, social security, the private health system, the Expanded Programme on Immunization and UNPop 2008.

RESULTS

Over the period studied, reductions were observed in trends of diarrhea-related deaths and hospitalizations in children under five. In diarrhea-related deaths, under the integral method, the range of reduction was between 15.7% (13.5-17.9) and 56.8% (56.0-57.5) while with the projection method was between 19.9% (4.9-34.8) and 63.7%(56.1-71.4). In diarrhea-related hospitalizations, under the integral method was 5.6% (4.1-6.7) and 17.9% (16.7-19.1)) while with the projection method was between 5.1%(1.7-8.7) and 11.1% (5.8-16.3) CONCLUSIONS: A decrease was observed in the number of diarrhea related deaths and hospitalizations in all countries under study following introduction of the rotavirus vaccine as opposed to the control country. The impact on reduction of deaths was greater than hospitalization.

Development of a cholera vaccination policy on the Island of Hispaniola, 2010-2013

Deployment of oral cholera vaccine (OCV) on the Island of Hispaniola has been considered since the emergence of the disease in October of 2010. At that time, emergency response focused on the time-tested measures of treatment to prevent deaths and sanitation to diminish transmission. Use of the limited amount of vaccine available in the global market was recommended for demonstration activities, which were carried out in 2012. As transmission continues, vaccination was recommended in Haiti as one component of a comprehensive initiative supported by an international coalition to eliminate cholera on the Island of Hispaniola. Leveraging its delivery to strengthen other cholera prevention measures and immunization services, a phased OCV introduction is pursued in accordance with global vaccine supply. Not mutually exclusive or sequential deployment options include routine immunization for children over the age of 1 year and campaigns in vulnerable metropolitan areas or rural areas with limited access to health services.

Considerations for oral cholera vaccine use during outbreak after earthquake in Haiti, 2010-2011

Oral cholera vaccines (OCVs) have been recommended in cholera-endemic settings and preemptively during outbreaks and complex emergencies. However, experience and guidelines for reactive use after an outbreak has started are limited. In 2010, after over a century without epidemic cholera, an outbreak was reported in Haiti after an earthquake. As intensive nonvaccine cholera control measures were initiated, the feasibility of OCV use was considered. We reviewed OCV characteristics and recommendations for their use and assessed global vaccine availability and capacity to implement a vaccination campaign. Real-time modeling was conducted to estimate vaccine impact. Ultimately, cholera vaccination was not implemented because of limited vaccine availability, complex logistical and operational challenges of a multidose regimen, and obstacles to conducting a campaign in a setting with population displacement and civil unrest. Use of OCVs is an option for cholera control; guidelines for their appropriate use in epidemic and emergency settings are urgently needed.

Vaccination Week in the Americas: an opportunity to integrate other health services with immunization

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.

Measles and rubella elimination initiatives in the Americas: lessons learned and best practices

Countries in the World Health Organization Region of the Americas successfully interrupted endemic measles virus transmission 8 years after setting a regional measles elimination goal and have sustained this achievement since 2002. The vast experience from the region clearly demonstrates that measles elimination can be accomplished and maintained over time. This brief report summarizes the lessons learned and the best practices that evolved in the Americas during 3 measles elimination phases (ie, preelimination, elimination, and postelimination phases), as well as the contribution of rubella elimination to strengthening and maintaining measles elimination. The effective measures that have been implemented and adapted by the countries of the Americas to eliminate endemic measles and rubella will serve as an example to other countries and regions embarking on this endeavor.

Guillain-Barré syndrome in children aged <15 years in Latin America and the Caribbean: baseline rates in the context of the influenza A (H1N1) pandemic

In light of the influenza A (H1N1) pandemic, the Strategic Advisory Group of Experts on Immunization of the World Health Organization requested that the acute flaccid paralysis surveillance system of Latin American and the Caribbean be used to establish Guillain-Barré syndrome incidence rates. An analysis was conducted of 10,486 acute flaccid paralysis cases diagnosed as Guillain-Barré syndrome from 2000 through 2008 in children aged <15 years in Latin American and the Caribbean countries and territories. The average incidence was 0.82 cases per 100,000 children aged <15 years (range, 0.72-0.90 cases per 100,000 children), with significant differences between northern and southern countries (1.08 vs 0.57 cases per 100,000 children). The acute flaccid paralysis surveillance system represents a useful means of monitoring Guillain-Barré syndrome during the pandemic.

Expansion of seasonal influenza vaccination in the Americas

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.

METHODS

To assess the status of influenza vaccination in the Americas, influenza vaccination data reported to the Pan American Health Organization (PAHO) through 2008 were analyzed.

RESULTS

Thirty-five countries and territories administered influenza vaccine in their public health sector, compared to 13 countries in 2004. Targeted risk groups varied. Sixteen countries reported coverage among older adults, ranging from 21% to 100%; coverage data were not available for most countries and targeted populations. Some tropical countries used the Northern Hemisphere vaccine formulation and others used the Southern Hemisphere vaccine formulation. In 2008, approximately 166.3 million doses of seasonal influenza vaccine were purchased in the Americas; 30 of 35 countries procured their vaccine through PAHO's Revolving Fund.

CONCLUSION

Since 2004 there has been rapid uptake of seasonal influenza vaccine in the Americas. Challenges to fully implement influenza vaccination remain, including difficulties measuring coverage rates, variable vaccine uptake, and limited surveillance and effectiveness data to guide decisions regarding vaccine formulation and timing, especially in tropical countries.

Survey of drug resistance of Mycobacterium tuberculosis in 3 Mexican states, 1997

BACKGROUND

Drug resistance threatens global tuberculosis (TB) control efforts. Population-based estimates of drug resistance are needed to develop strategies for controlling drug-resistant TB in Mexico.

OBJECTIVE

To obtain population-based data on Mycobacterium tuberculosis drug resistance in Mexico.

METHODS

To obtain drug resistance data, we conducted a population-based study of TB cases in the states of Baja California, Sinaloa, and Oaxaca, Mexico. We performed cultures and drug susceptibility testing on M tuberculosis isolates from patients with newly diagnosed, smear-positive TB from April 1 to October 31, 1997.

RESULTS

Mycobacterium tuberculosis was isolated from 460 (75%) of the 614 patients. Levels of resistance in new and retreatment TB cases to 1 or more of the 3 current first-line drugs used in Mexico (isoniazid, rifampin, and pyrazinamide) were 12.9% and 50.5%, respectively; the corresponding levels of multi-drug-resistant TB were 2.4% and 22.4%. Retreatment cases were significantly more likely than new cases to have isolates resistant to 1 or more of the 3 first-line drugs (relative risk [RR], 3.9; 95% confidence interval [CI], 2.8-5.5), to have isoniazid resistance (RR, 3.6; 95% CI, 2.5-5.2), and to have multi-drug-resistant TB (RR, 9.4; 95% CI, 4.3-20.2).

CONCLUSIONS

This population-based study of M tuberculosis demonstrates moderately high levels of drug resistance. Important issues to consider in the national strategy to prevent M tuberculosis resistance in Mexico include consideration of the most appropriate initial therapy in patients with TB, the treatment of patients with multiple drug resistance, and surveillance or periodic surveys of resistance among new TB patients to monitor drug resistance trends.

Five cases of primary amebic meningoencephalitis in Mexicali, Mexico: study of the isolates

Five Naegleria strains isolated from patients with primary amebic meningoencephalitis and one strain isolated from the water of an artificial canal were investigated. All strains were pathogenic for mice when instilled intranasally and showed cytopathic effects in Vero cell cultures. Their growth characteristics (isolation and subculture at 45 degrees C), serological results, and isoenzyme patterns permitted us to identify the six strains as Naegleria fowleri. This is the first time that Naegleria fowleri has been isolated from patients with primary amebic meningoencephalitis in Mexico.

[Epidemiologic investigation of measles in Mexico. A methodological proposal]

The epidemiological study of measles needs a critical perspective in addition to a descriptive study of variables in time, place and person. The goal of this critical and methodological study of measles is to evaluate the coverage and efficacy of the vaccine in the affected population. These indicators will provide an indirect evaluation of the preventable services. This document presents a general view of the epidemiological design of cohorts and case-control studies and their immediately application to the study of measles. It describe the mathematical procedures for calculating the coverage and efficacy of the measles vaccine in community and hospital outbreaks.

[Epidemiologic study of a whooping cough outbreak in Rincón Grande, Veracruz]

An outbreak of whooping cough occurred in February 1988 in the town of Rincon Grande, borough of Santa Ana Atzacan, Veracruz. The objectives of this study were: to corroborate the presence of infection by Bordetella pertussis, to survey the immunizational status against this organism in this population, to identify the etiologic agent involved and the main epidemiologic characteristics of the outbreak. A descriptive study of the cases with the known population as well as a study of the cases and controls to identify the risk factors associated with illness were performed. Among the 461 inhabitants of the town of Rincon Grande, Veracruz, 85 cases were detected giving an attack rate of 18.4 per 100 inhabitants. The outbreak lasted 13 weeks with the highest incidence occurring from the 7th to the 13th of January 1988. The 7 to 11 month old group was the age group most affected having a rate of attack of 85%. The rate of secondary attacks was greater at the intrafamiliar level than at the scholastic level. The main symptoms included: the paroxysmal cough, fever, stridor, epistaxis and conjunctival hemorrhage. Among the complications found were: pneumonia, hemotympanus and dehydration; 84% of the affected children showed leukocytosis and lymphocytosis. The determination of serum B. pertussis antibody levels, demonstrated high levels in 60% of the paired samples. In 14% of the patients there was serologic evidence of an association with an adenovirus infection. The study of the cases and the controls revealed that living with 10 or more persons in the same room, and that having an intrafamiliar contact represented a greater risk for acquiring the disease (odds ratio = 21, P less than 0.05). The immunization survey revealed low coverage (6%) in this locale.

[Postneonatal mortality caused by diarrhea: a case-control study]

A matched case-control study was undertaken in Naucalpan de Juárez, Estado de México. The goal of this study was to identify the risk factors for diarrheal disease in children between seven days and one year of age. We identified 63 case and 188 controls. The most important risk factors were: mother's age greater than 36 years with an odds ratis (OR) 3.7, lack of breastfeeding (OR 11.3), breast and bottle feeding (OR 5.4), lack of intradomiciliary sewage (OR 8.3), repeated episoded of disease (OR 8.6) and father's consumption alcoholic beverages (OR 3.6). The main possible paths by which these factors influence mortality are discussed. Specific interventions for some of the factors are proposed.