Childhood vaccination: achievements and challenges

As the goal of eradicating smallpox was being met, the World Health Organization created its Expanded Programme on Immunisation (EPI) in 1974 and reached its initial goal of achieving full vaccination of 80% of the world's children by 1990. This effort was aided by the creation of "cold chain" delivery systems and resulted in the annual saving of 3.5 million children in less-developed countries. Current EPI vaccination goals include 1) eradication of poliomyelitis by the year 2000, 2) elimination of neonatal tetanus by the year 1995, 3) control of measles and hepatitis B, and 4) immunization of 90% of the world's children 1 year or younger by the year 2000. Goals of the Children's Vaccine Initiative (formed in 1991) include 1) provision of an adequate supply of affordable, safe, and effective vaccines; 2) production of improved and new vaccines; and 3) simplification of the logistics of vaccine delivery. Future challenges are to sustain high vaccination coverage, reach the unreached, achieve proper storage of vaccines and reduce waste, integrate new vaccines into national programs, and achieve vaccine self-sufficiency. The fact that these challenges will be difficult to achieve is illustrated by the situation in Africa where the high immunization levels achieved in 1990 have dropped dramatically. Those who must act to implement immunization programs are health personnel, families, governments, and development partners. In order to achieve equity in health, every child must be reached, governments must be made accountable for programs, health workers must convince families of the importance of vaccination, delivery systems must be in place to take advantage of the new vaccines being delivered, and a multisectoral approach must be taken to assure sustainability.     

Global immunization: status,progress, challenges and future

Vaccines have made a major contribution to public health, including the eradication of one deadly disease, small pox, and the near eradication of another, poliomyelitis.Through the introduction of new vaccines, such as those against rotavirus and pneumococcal diseases, and with further improvements in coverage, vaccination can significantly contribute to the achievement of the health-related United Nations Millennium Development Goals.The Global Immunization Vision and Strategy (GIVS) was developed by WHO and UNICEF as a framework for strengthening national immunization programmes and protect as many people as possible against more diseases by expanding the reach of immunization, including new vaccines, to every eligible person.This paper briefly reviews global progress and challenges with respect to public vaccination programmes.The most striking recent achievement has been that of reduction of global measles mortality from an estimated 750,000 deaths in 2000 down to 197,000 in 2007. Global vaccination coverage trends continued to be positive. In 2007 most regions reached more than 80% of their target populations with three doses of DPT containing vaccines. However, the coverage remains well short of the 2010 goal on 90% coverage, particularly in the WHO region of Africa (estimated coverage 74%), and South-East Asia, (estimated coverage 69%). Elements that have contributed to the gain in immunization coverage include national multi-year planning, district-level planning and monitoring, re-establishment of outreach services and the establishment of national budget lines for immunization services strengthening.Remaining challenges include the need to: develop and implement strategies for reaching the difficult to reach; support evidence-based decisions to prioritize new vaccines for introduction; strengthening immunization systems to deliver new vaccines; expand vaccination to include older age groups; scale up vaccine preventable disease surveillance; improve quality of immunization coverage monitoring and use the data to improve programme performance; and explore financing options for reaching the GIVS goals, particularly in lower-middle income countries.Although introduction of new vaccines is important,this should not be at the expense of sustaining existing immunization activities. Instead the introduction of new vaccine introduction should be viewed as an opportunity to strengthen immunization systems, increase vaccine coverage and reduce inequities of access to immunization services.     

Measles eradication: experience in the Americas

In 1994, the Ministers of Health from the Region of the Americas targeted measles for eradication from the Western Hemisphere by the year 2000. To achieve this goal, the Pan American Health Organization (PAHO) developed an enhanced measles eradication strategy. First, a one-time-only "catch-up" measles vaccination campaign is conducted among children aged 9 months to 14 years. Efforts are then made to vaccinate through routine health services ("keep-up") at least 95% of each newborn cohort at 12 months of age. Finally, to assure high population immunity among preschool-aged children, indiscriminate "follow-up" measles vaccination campaigns are conducted approximately every 4 years. These vaccination activities are accompanied by improvements in measles surveillance, including the laboratory testing of suspected measles cases. The implementation of the PAHO strategy has resulted in a marked reduction in measles incidence in all countries of the Americas. Indeed, in 1996 the all-time regional record low of 2109 measles cases was reported. There was a relative resurgence of measles in 1997 with over 20,000 cases, due to a large measles outbreak among infants, preschool-aged children and young adults in S?o Paulo, Brazil. Contributing factors for this outbreak included: low routine infant vaccination coverage, failure to conduct a "follow-up" campaign, presence of susceptible young adults, and the importation of measles virus, apparently from Europe. PAHO's strategy has been effective in interrupting measles virus circulation. This experience demonstrates that global measles eradication is an achievable goal using currently available measles vaccines.     

Vaccination, smallpox, and a culture of immunization in Brazil

The aim of this paper is to discuss the emergence and establishment of a "culture of immunization" in the contemporary Brazil from the eradication of smallpox. This culture is associated with a long process of introduction of vaccines, vaccination campaigns and mass vaccination undertaken by the Brazilian government since the late nineteenth century. Particular importance is attributed to the campaign to eradicate smallpox in Brazil (1966-1973). The experience of mass vaccination of the population against smallpox is contrasted with episodes of resistance as the "revolt against the vaccine", and regarded as crucial in shaping new policies and new understandings about the role of immunization in public health and its place in society Brazil.     

Smallpox eradication in West and Central Africa

In 1966, a programme to eradicate smallpox and control measles began in West and Central Africa. With WHO and US bilateral technical and financial assistance, the 20 countries mounted a coordinated campaign of mass vaccination, assessment, surveillance, and maintenance activities. The last cases of smallpox occurred in May 1970. The introduction of epidemiologically directed surveillance-containment activities and their rapid success resulted in interruption of smallpox transmission much sooner than anticipated. The area has remained free of smallpox. From 1966 to 1972, over 28 000 000 children 1-6 years of age also received measles vaccination. The campaign established or strengthened structures for preventive health care services in all the countries.     

The immunisation programme in the Caribbean

The Directing Council of Pan American Health Organization approved a resolution concerning the formal inauguration of the Expanded Programme on Immunization (EPI) in the Americas in October 1977. Subsequently, the EPI entered full implementation in those countries that were members of the Caribbean Epidemiology Center (CAREC) during 1978-80. All 19 CAREC Member Countries (CMC) were conducting routine immunization with diphtheria, pertussis, tetanus, poliomyelitis, measles and BCG vaccines by 1980. The establishment of the program in these countries resulted in focused activities, including training and the development of operational guidelines. Health education has been primarily used to encourage mothers to have their children vaccinated at optimum age, and to advise parents and guardians about adverse reaction to vaccines. Great efforts have been made in immunization coverage in all the CMCs for the six vaccine preventable diseases. The eradication of poliomyelitis, the interruption of measles transmission (8 years measles-free), and the implementation of strategies for the elimination of rubella and CRS have presented many challenges to public health practitioners in the region. The success of all these initiatives is a reflection of the deep commitment and strong partnerships, which have been developed between the governments, health practitioners, and people of the region. Moreover, technical and financial support from both international agencies and service clubs played a major role in the success of the program.     

Demographic impact of vaccination: a review

Vaccination is one of the most powerful means to save lives and to increase the level of health of mankind. However, the impact of immunization against the most threatening infectious agents on life expectancy has been the object of a still open debate. The main issues are: the relative influence of nutrition and infectious diseases on demographic patterns of populations; the possibility that lives saved thanks to vaccination are subsequently lost due to other competing causes of death; the positive indirect effect of immunization on other causes of death. With regard to past evidence, several data from the United Kingdom and Scandinavian countries show that the widespread use of smallpox vaccination starting at the beginning of the nineteenth century resulted in a marked and sustained decline not only of smallpox-related deaths, but also of the overall crude death rate, and contributed greatly to an unprecedented growth of European population. As to the present, it is estimated that 3 million children are saved annually by vaccination, but 2 million still die because they are not immunized. Tetanus, measles and pertussis are the main vaccine-preventable killers in the first years of life. Data from Bangladesh show that full implementation of EPI vaccines has the potential of reducing mortality by almost one half in children aged 1-4 years. Recent progress in the development of vaccines against agents responsible for much mortality in the developing countries make it possible to forecast a further substantial reduction of deaths for infectious diseases in the next century.     

The impact of the national polio immunization campaign on levels and equity in immunization coverage: evidence from rural North India

Few studies have investigated the impact of immunization campaigns conducted under the global polio eradication program on sustainability of polio vaccination coverage, on coverage of non-polio vaccines (administered under Expanded Program on Immunization (EPI)), and on changes in social inequities in immunization coverage. This study proposes to fill the gaps in the evidence by investigating the impact of a polio immunization campaign launched in India in 1995. The study uses a before-and-after study design using representative samples from rural areas of four North Indian states. The National Family Health Survey I (NFHS I) and NFHS II, conducted in 1992-93 and 1998-99 respectively, were used as pre- and post-intervention data. Using pooled data from both the surveys, multivariate logistic regression models with interaction terms were used to investigate the changes in social inequities.During the study period, a greater increase was observed in the coverage of first dose of polio compared to three doses of polio. Moderate improvements in at least one dose of non-polio EPI vaccinations, and no improvements in complete immunization against non-polio EPI diseases were observed. The polio campaign was successful, to some extent, in reducing gender-, caste- and wealth-based inequities, but had no impact on religion- or residence-based inequities. Social inequities in non-polio EPI vaccinations did not reduce during the study period. Significant dropouts between first and third dose of polio raise concerns of sustainability of immunization coverage under a campaign approach. Similarly, little evidence to support synergy between polio campaign and non-polio EPI vaccinations raises questions about the effects of polio campaign on routine health system's functions. However, moderate success of the polio campaign in reducing social inequities in polio coverage may offer valuable insights into the routine health systems for addressing persistent social inequities in access to health care.     

Measles and rubella eradication in the Americas

The challenge for regions embarking on measles elimination will be to maintain high population immunity with excellent vaccination coverage and high-quality surveillance. Meeting this challenge will be especially critical for dealing with importations of measles virus that will occur as long as the virus is circulating anywhere in the world. Implementation of measles elimination strategies will uncover the "hidden" disease burden of rubella and congenital rubella syndrome. As was the experience in countries of Latin America and the Caribbean (LAC), integrating the elimination of measles with the elimination of rubella will greatly enhance the capacity of countries to sustain progress in the reduction of measles mortality. Countries of LAC prioritized the routine national immunization program over short-term successes. While doing so, they have also encountered new opportunities to expand the benefits of disease control and elimination activities to other aspects of public health, most importantly towards improving health care for women and newborns and reducing inequities in health in the region's poorest communities. Implementation of similar strategies could lead to the global eradication of measles, rubella, and congenital rubella syndrome early this century, while strengthening routine immunization programs, and developing the capacity to introduce new and underutilized vaccines.     

Effektivität, Populationseffekte und Gesundheitsökonomie der Impfungen gegen Masern und Röteln

Vaccination against measles and rubella has been included in national immunization programs worldwide for several decades. In this article, we present the evidence related to the effectiveness of measles and rubella vaccination based on published systematic reviews, and we describe the epidemiological and health economic effects of vaccination at a population level. Several observational studies demonstrate the high effectiveness (>?90?%) of both measles and rubella vaccination. The global measles mortality reduction and the dramatic decrease in rubella and measles incidences after introduction of routine immunization contribute to the very high quality of evidence. The countries of the Americas have proved that it is feasible to eliminate measles and rubella by strengthening infant immunization through routine vaccination services and by conducting supplemental immunization activities in other childhood age groups so as to close immunity gaps. An economic evaluation of measles and rubella vaccination specifically for the healthcare system in Germany does not exist. However, we conducted a systematic review and identified 11 health-economic studies from other industrialized countries and one for a hypothetical industrialized country. Results indicate that vaccination against measles and rubella had either a cost-effective or even a cost-saving potential, which could be assumed with some limitations also for the German setting. In conclusion, there is compelling evidence that the available vaccines are very effective and that measles and rubella elimination is feasible if adequate vaccination strategies are implemented. In Germany, catch-up vaccination programs are urgently needed for children, adolescents, and young adults specifically in the western federal states.     

Immunization

Immunization is an essential component of primary health care and child survival activities throughout the world. Since the establishment of the World Health Organization's Expanded Programme on Immunization (EPI) in 1974, the estimated incidence of childhood vaccine-preventable diseases has declined significantly. Today, immunization against the 6 diseases targeted by EPI--diphtheria, measles, pertussis, polio, tetanus and tuberculosis--prevents approximately 2 million childhood deaths per year. Nevertheless, many women and children in the developing world remain unimmunized, resulting in the death or disability from vaccine-preventable diseases of over 3 million children annually. Currently, efforts are focused on expanding immunization services for women and children with the goal of protecting all children against the 6 EPI-targeted diseases. Recent initiatives call for the eradication of polio by 2000, the elimination of neonatal tetanus by 1995, and a 95% reduction in measles incidence by 1995. Expanding immunization coverage against hepatitis B and yellow fever also are objectives in areas where these diseases are endemic. To achieve these goals, current immunization program priorities include: 1) the continued use of current vaccines as well as the introduction of new more effective, and more stable ones; 2) the development and improvement of cold chain technologies to safely transport, store, and distribute vaccines; 3) the development and improvement of injection technologies to ensure proper administration of vaccines and safe handling of injection equipment; and 4) efficient program management that strives to achieve and sustain expanded coverage and service delivery through improved training, supervision, evaluation and community mobilization. The most recent developments in these areas are reviewed, updating a 1983 "Directions" issue on the same topic.     

Vaccines, immunization and technological innovation: an update

The smallpox worldwide eradication was the major world public health achievement. The binomial - vaccines and immunization - continues to demonstrate very high performance in the prevention and control of other diseases preventable by vaccination. The new global initiatives on vaccination, such as GAVI, have made possible the introduction of new and important vaccines preventing million of children deaths in the poorest countries in the world. The National Immunization Program of Brazil is also being strengthened, with the introduction of several new vaccines into the basic calendar as rotavirus, pneumococcal and meningococcal conjugated and H1N1 in national campaign, covering the population at risk. With the discovery of high valued vaccines, the big pharmaceutical companies became interested in this area, investing heavily in technological innovation, making fusions, acquisitions and technological partnerships. Brazil has also established a new innovation policy, creating new laws as well as subsidizing projects in technological innovation and modernization of production infra-structure.     

Difficulties in measles elimination: prevalence of measles antibodies before and after mass vaccination campaign in Laos

Responding to the declaration of regional polio eradication in 2000, Western Pacific Region (WPR) has been strengthening the efforts for measles elimination. Nevertheless, we questioned the feasibility of the measles elimination in Laos, where measles was still endemic. This study was undertaken with the aim to examine the impact of mass measles vaccination campaign, by comparing the prevalence of measles antibodies between before and after the campaign in 2000, among the children aged 9 months to 4 years in the two pilot sites. The constraints of mass vaccination campaign have been explored in this study. It was also suggested that more efforts should be put on reconstruction of the existing routine immunization service in Laos, which had been weakened by aggressive eradication programme.     

Impact of measles supplementary immunization activities on reaching children missed by routine programs

BackgroundMeasles supplementary immunization activities (SIAs) are vaccination campaigns that supplement routine vaccination programs with a recommended second dose opportunity to children of different ages regardless of their previous history of measles vaccination. They are conducted every 2–4 years and over a few weeks in many low- and middle-income countries. While SIAs have high vaccination coverage, it is unclear whether they reach the children who miss their routine measles vaccine dose. Determining who is reached by SIAs is vital to understanding their effectiveness, as well as measure progress towards measles control.MethodsWe examined SIAs in low- and middle-income countries from 2000 to 2014 using data from the Demographic and Health Surveys. Conditional on a child’s routine measles vaccination status, we examined whether children participated in the most recent measles SIA.ResultsThe average proportion of zero-dose children (no previous routine measles vaccination defined as no vaccination date before the SIA) reached by SIAs across 14 countries was 66%, ranging from 28% in São Tomé and Príncipe to 91% in Nigeria. However, when also including all children with routine measles vaccination data, this proportion decreased to 12% and to 58% when imputing data for children with vaccination reported by the mother and vaccination marks on the vaccination card across countries. Overall, the proportions of zero-dose children reached by SIAs declined with increasing household wealth.ConclusionsSome countries appeared to reach a higher proportion of zero-dose children using SIAs than others, with proportions reached varying according to the definition of measles vaccination (e.g., vaccination dates on the vaccination card, vaccination marks on the vaccination card, and/or self-reported data). This suggests that some countries could improve their targeting of SIAs to children who miss other measles vaccine opportunities. Across all countries, SIAs played an important role in reaching children from poor households.     

Strengthening routine immunization through measles-rubella elimination

The 2016 mid-term review of the Global Measles-Rubella Strategic Plan 2012–20 for achieving measles-rubella elimination concluded that the full potential of strategies and activities to strengthen routine immunization (RI) service delivery had not been met. In December 2017, we contacted WHO and partner agency immunization staff in all six WHO Regions who identified 23 countries working on measles or rubella elimination that have implemented examples of recommended activities to improve RI, adapted to their needs. Among those examples, opportunities to strengthen RI through implementing supplementary immunization activities (SIAs) were reported most frequently, including advocacy for immunization and educational activities targeted at the public and skills training targeted at health professionals. The expansion of cold chain capacity to accommodate supplies required for SIAs facilitated widening RI service delivery to reach more communities, introduce new vaccines, and reduce the risk of vaccine stock-outs. Substantial numbers of under-vaccinated children, according to the national immunization schedule, have been identified during SIAs, but it is not possible to confirm whether these children actually received missing RI doses. Micro-planning exercises for SIAs have generated data that permitted the revision of catchment populations for fixed site and outreach RI services. Some countries reported using the opportunity afforded by measles/rubella elimination to strengthen overall vaccine-preventable disease surveillance and outbreak preparedness and to introduce mandatory school-entry vaccination requirements covering other vaccines in addition to measles and rubella. Unfortunately, we were unable to obtain information regarding the cost, impact or sustainability of these activities. The evaluation of the many other strategies that have been deployed in recent years to strengthen RI systems and raise vaccination coverage was beyond the scope of this survey. We conclude by providing recommendations to encourage more countries to adapt and implement a comprehensive set of RI-strengthening activities in association with the MR elimination goal.     

Vaccines to prevent pneumonia and improve child survival

For more than 30 years, vaccines have played an important part in pneumonia prevention. Recent advances have created opportunities for further improving child survival through prevention of childhood pneumonia by vaccination. Maximizing routine immunization with pertussis and measles vaccines, coupled with provision of a second opportunity for measles immunization, has rapidly reduced childhood deaths in low-income countries especially in sub-Saharan Africa. Vaccines against the two leading bacterial causes of child pneumonia deaths, Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (pneumococcus), can further improve child survival by preventing about 1,075,000 child deaths per year. Both Hib and pneumococcal conjugate vaccines have proven safety and effectiveness for prevention of radiologically confirmed pneumonia in children, including in low-income and industrializing countries. Both are recommended by WHO for inclusion in national programmes, and, at sharply tiered prices, these vaccines generally meet international criteria of cost-effectiveness for low-income countries. Vaccines only target selected pneumonia pathogens and are less than 100% effective, so they must be complemented by curative care and other preventative strategies. As part of a comprehensive child survival package, the particular advantages of vaccines include the ability to reach a high proportion of all children, including those who are difficult to reach with curative health services, and the ability to rapidly scale up coverage with new vaccines. In this review, we discuss advances made in optimizing the use of established vaccines and the potential issues related to newer bacterial conjugate vaccines in reducing childhood pneumonia morbidity and mortality.     

New vaccine introduction in the East and Southern African sub-region of the WHO African region in the context of GIVS and MDGs

Immunization programmes have over the years proven to be effective and useful in infectious disease control. However, based on current trends that show that many developing countries will not reach the Millennium Development Goals (MDG) targets, there is an urgent need to accelerate efforts to control the most common conditions still responsible for the largest morbidity and mortality in children under 5 years of age, like diarrhoea and pneumonia, for which safe and effective vaccines are now available. Through World Health Organization (WHO) and United Nations Children's Fund (UNICEF) strategies and initiatives like the Global Immunization Vision and Strategy (GIVS), Accelerated Disease Control and Reach Every District (RED), major positive achievements like the increasing number of children reached with Diphtheria-Tetanus-Pertussis (DTP) vaccines, significant measles mortality reduction, and the almost complete eradication of polio, have been realised. Many children in developing countries have access to life saving vaccines through the Global Alliance for Vaccines and Immunization (GAVI) support. Supplementary immunization activities against measles and polio continue to offer opportunities to deliver measles and polio vaccines, and other life-saving interventions. The Global Immunization Vision and Strategy 2006-2015 (GIVS framework) can effectively be used to guide countries in addressing some of the remaining challenges to reach the unreached and increase coverage of traditional vaccines, immunize more people against more diseases, support decision making to introduce new vaccines, as well as recognize the opportunity to invest in community health through cost-effective immunization programmes. Introduction of new vaccines should be strengthened and used as vehicles for health systems strengthening as well as for delivery of comprehensive primary health interventions to impact positively on the spiralling disease burden and reduce overall child mortality. A number of countries have adopted and operationalized GIVS through comprehensive multi-year plans for immunization (cMYP). This paper reviews progress with respect to introduction of some of the new vaccines in the East and Southern sub-region of WHO African region in the context of GIVS and MDGs as well as the challenges thereof.     

Economic analysis of the 1996-1997 mass measles immunization campaigns in South Africa

To evaluate economic implications of conducting a "catch-up" measles vaccination campaign, we conducted an economic analysis of the 1996-1997 measles immunization campaign in two provinces of South Africa comparing the baseline two-dose routine immunization program to the combined vaccination strategy (routine two-dose immunization program, plus the 1996-1997 campaign). The study findings indicate that the 1996-1997 mass measles immunization campaign was cost-effective in both study provinces, and cost-saving in the province with higher pre-campaign disease incidence and lower routine vaccination coverage. An early investment in effective vaccination strategies that rapidly reduce disease burden apparently results in better returns, both epidemiologically and economically.     

Global public health mandates in a diverse world: the polio eradication initiative and the expanded programme on immunization in sub-Saharan Africa and South Asia

BACKGROUND: The circulation of wild poliovirus is expected to cease soon due to the success of the global polio eradication initiative. Thereafter, intensified polio eradication efforts such as National Immunisation Days (NIDs) will most likely be discontinued. As a consequence, the expanded programme on immunization (EPI) will no longer enjoy extra inputs from the polio eradication initiative. We investigated whether today's EPIs are ensuring universal and equitable vaccine coverage; and whether the removal of extra inputs associated with the implementation of NIDs is likely to affect EPI coverage and equity. METHODS: Using data from Demographic and Health Surveys conducted in 15 countries of South Asia and Africa during 1990-2001, we examined absolute levels of EPI coverage; changes in EPI coverage after the introduction of NIDs; and relative coverage according to urban versus rural residence, higher versus lower education of mothers, and wealthiest vs. poorest population segment. RESULTS: Polio and non-polio antigen coverage increased in seven countries during the study period. Substantial inequalities in coverage of non-polio antigens persist, however, translating into inequities in the risk of contracting vaccine preventable diseases. In some African countries, routine EPI coverage and/or equity declined during the study period. In these countries, any positive effect of NIDs on the EPI coverage must have been small, relative to the negative effects of declining economies or deteriorating health systems. In Nigeria, Zimbabwe, Kenya and Malawi, even polio coverage declined, in spite of the introduction of NIDs. CONCLUSION: As additional inputs associated with polio eradication will cease, routine EPI services need to be strengthened substantially in order to maintain levels of population immunity against polio and to improve social equity in the coverage of non-polio EPI antigens. Our findings imply that this aim will require additional inputs, particularly in African countries.     

Assessment of vaccination coverage, vaccination scar rates, and smallpox scarring in five areas of West Africa

In 1966, nineteen countries of West and Central Africa began a regional smallpox eradication and measles control programme in cooperation with the World Health Organization. This paper summarizes sample survey data collected to assess the results of the programme in Northern Nigeria (Sokoto and Katsina Provinces), Western Nigeria, Niger, Dahomey, and Togo. These data indicate that the programme, which used mass vaccination campaigns based on a collecting-point strategy, was generally successful in reaching a high proportion of the population. Analysis of vaccination coverage and vaccination scar rates by age underlined the importance to the programme of newborn children who accumulate rapidly following the mass campaign. Of all persons without vaccination scars at the time of the surveys, 34.4% were under 5 years of age; in the absence of a maintenance programme, this figure would rise to 40% after 1 year.