Milestones :: Perspectives
Nationwide immunization campaign protects 5 million children against polio in war-torn Yemen
Joint WHO, UNICEF, World Bank news release
SANA’A, 8 April 2017— In an effort to keep Yemen polio-free, nearly 5 million children under the age of five have been vaccinated in a nationwide campaign covering all governorates in the country. The campaign was supported by a partnership between the World Bank, UNICEF and WHO launched in February 2017.
Despite intensifying violence in Sa’ada governorate, more than 369,000 children between the ages of 6 months and 15 years were immunized against measles – a highly contagious and potentially fatal disease – and over 155,000 children under the age of 5 were vaccinated against polio.
Thousands of dedicated health workers, health educators, religious leaders and local council officials played a key role in mobilizing their communities to maximize the immunization campaign’s reach. Thanks to their support, high-risk groups, such as internally displaced persons and refugees, have also been vaccinated.
“WHO, UNICEF and the World Bank, are working closely with health authorities to keep Yemen polio-free and curb the spread of measles,” said Dr Nevio Zagaria, WHO Representative in Yemen. “This partnership provides continuous support to national health authorities to increase vaccination coverage for vulnerable children across Yemen.”
The two year-long conflict in Yemen has all but destroyed the country’s health system, including the national immunization programme to protect all children from preventable diseases. WHO and UNICEF have provided sustained support for the programme, along with other essential health services for children, including:
:: Delivering fuel, generators and solar-powered refrigerators to keep vaccines at a constant cool temperature,
:: Support for transferring vaccines from national and governorate cold rooms to local health facilities and vaccination teams.
“Every minute, the situation of Yemen’s children gets worse. It is unacceptable that children in Yemen are dying of preventable diseases. This is why, together with partners, we are sparing no effort to save more lives,” said Ms. Meritxell Relaño, UNICEF Representative in Yemen.
“The World Bank is committed to investing in children’s health, which is a vital investment in the country’s future, through working with our UN partners in Yemen and strengthening the local health institutions” said Ms. Sandra Bloemenkamp, World Bank Country Manager for Yemen…
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Ten years in public health 2007-2017
By Dr Margaret Chan, Director-General, WHO
13 April 2017 – Today we begin the launch of “Ten years in public health 2007-2017” – a report that chronicles the evolution of global public health over the decade that I have served as Director-General at WHO.
This series of chapters, which will be published over the next 6 weeks, evaluates successes, setbacks, and enduring challenges during my administration. They show what needs to be done when progress stalls or new threats emerge. The chapters show how WHO technical leadership can get multiple partners working together in tandem under coherent strategies. The importance of country leadership and community engagement is stressed repeatedly throughout the chapters.
Together we have made tremendous progress. Health and life expectancy have improved nearly everywhere. Millions of lives have been saved. The number of people dying from malaria and HIV has been cut in half. WHO efforts to stop TB saved 49 million lives since the start of this century. In 2015, the number of child deaths dropped below 6 million for the first time, a 50% decrease in annual deaths since 1990. Every day 19000 fewer children die. We are able to count these numbers because of the culture of measurement and accountability instilled in WHO.
The challenges facing health in the 21st century are unprecedented in their complexity and universal in their impact. Under the pressures of demographic ageing, rapid urbanization, and the globalized marketing of unhealthy products, chronic noncommunicable diseases have overtaken infectious diseases as the leading killers worldwide. Increased political attention to combat heart attacks and stroke, cancer, diabetes, and chronic respiratory diseases is welcome as a powerful way to improve longevity and healthy life expectancy. However, no country in the world has managed to turn its obesity epidemic around in all age groups. I personally welcome is the political attention being given to women, their health needs, and their contributions to society. Investment in women and girls has a ripple effect. All of society wins in the end.
Lessons learned from the 2014 Ebola outbreak in West Africa catalysed the establishment of WHO’s new Health Emergencies Programme, enabling a faster, more effective response to outbreaks and emergencies. The R&D Blueprint, developed following the Ebola response, cuts the time needed to develop and manufacture new vaccines and other products from years to months, accelerating the development of countermeasures for diseases such as Zika virus. For example, in December 2016, WHO was able to announce that the Ebola vaccine conferred nearly 100% protection in clinical trials conducted in Guinea.
The chapters reveal another shared priority for WHO: fairness in access to care as an ethical imperative. No one should be denied access to life-saving or health-promoting interventions for unfair reasons, including those with economic or social causes. That principle is profoundly demonstrated in WHO’s work on universal health coverage, which in the past decade has expanded from a focus on primary health care to the inclusion of UHC as a core element of the 2030 Agenda for Sustainable Development. Health has a central place in the global goals. Importantly, countries have committed to this powerful social equalizer. Universal health coverage reflects the spirit of the SDGs and is the ultimate expression of fairness, ensuring no one is left behind.
These chapters tell a powerful story of global challenges and how they have been overcome. In a world facing considerable uncertainty, international health development is a unifying – and uplifting – force for the good of humanity. I have been proud to witness this impressive spirit of collaboration and global solidarity.
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Featured Journal Content
PNAS – Proceedings of the National Academy of Sciences of the United States
of America
http://www.pnas.org/content/early/
[Accessed 15 April 2017]
Editorial – Biological Sciences – Medical Sciences:
Simply put: Vaccination saves lives
Walter A. Orenstein and Rafi Ahmed
PNAS 2017 ; published ahead of print April 10, 2017, doi:10.1073/pnas.1704507114
Extract
Few measures in public health can compare with the impact of vaccines. Vaccinations have reduced disease, disability, and death from a variety of infectious diseases. For example, in the United States, children are recommended to be vaccinated against 16 diseases (1). Table 1 highlights the impact in the United States of immunization against nine vaccine-preventable diseases, including smallpox and a complication of one of those diseases, congenital rubella syndrome, showing representative annual numbers of cases in the 20th century compared with 2016 reported cases (2, 3). All of the diseases have been reduced by more than 90% and many have either been eliminated or reductions of 99% or more have been achieved. A recent analysis of vaccines to protect against 13 diseases estimated that for a single birth cohort nearly 20 million cases of diseases were prevented, including over 40,000 deaths (4). In addition to saving the lives of our children, vaccination has resulted in net economic benefits to society amounting to almost $69 billion in the United States alone. A recent economic analysis of 10 vaccines for 94 low- and middle-income countries estimated that an investment of $34 billion for the immunization programs resulted in savings of $586 billion in reducing costs of illness and $1.53 trillion when broader economic benefits were included (5). The only human disease ever eradicated, smallpox, was eradicated using a vaccine, and a second, polio, is near eradication, also using vaccines (6, 7)…
Vaccines not only provide individual protection for those persons who are vaccinated, they can also provide community protection by reducing the spread of disease within a population (Fig. 1). Person-to-person infection is spread when a transmitting case comes in contact with a susceptible person. If the transmitting case only comes in contact with immune individuals, then the infection does not spread beyond the index case and is rapidly controlled within the population. Interestingly, this chain of human-to-human transmission can be interrupted, even if there is not 100% immunity, because transmitting cases do not have infinite contacts; this is referred to as “herd immunity” or “community protection,” and is an important benefit of vaccination.
Mathematical modelers can estimate on average how many persons the typical transmitting case is capable of infecting if all of the contacts were susceptible (i.e., a population of 100% susceptibility). This number is known as R0, or the basic reproductive number. The immunity threshold needed within the population for terminating transmission can be calculated in percent as (R0 − 1)/R0 × 100 and is a guide to setting immunity levels and vaccination coverage targets for various diseases (8). For example, measles is one of the most contagious of vaccine-preventable diseases, with an estimated immunity threshold of 92–94%. In contrast, the protection threshold for rubella is estimated at 83–85%. Thus, eliminating rubella transmission is easier than measles, and when there are gaps in immunization coverage leading to accumulation of susceptibles, measles is often the first vaccine-preventable disease identified. Because of community protection induced by vaccines, persons who cannot be vaccinated (e.g., have contraindications or are younger than the age for whom vaccines are recommended), as well as persons who fail to make an adequate immune response to the vaccine (although most vaccines are highly effective, they are not 100% effective), can be protected indirectly because they are not exposed (Fig. 1). Thus, for most vaccines, achieving high levels of coverage is important not only for individual protection but in preventing disease in vulnerable populations that cannot be directly protected by vaccination. This provides the rationale for interventions to achieve high population immunity, such as removing barriers that may prevent access to vaccines (e.g., providing recommended vaccines without cost), as well as mandates for immunization requirements for attending school (9). There are many reasons why vaccinations may not be received as recommended. One extreme is outright opposition to vaccines. Probably even more common may be that making the effort to receive vaccines (e.g., making the healthcare visits at the appropriate time so vaccines can be administered) may be a low priority compared with other issues, so in the absence of having a mandate for vaccination, other things take priority. Thus, appropriate mandates could help in making vaccination a priority for all (10).
It’s often said that vaccines save lives, but this is not strictly true; it is vaccination that saves lives. A vaccine that remains in the vial is 0% effective even if it is the best vaccine in the world. Thus, it is imperative that we all work together to assure that a high level of coverage is obtained among populations for whom vaccines are recommended. In some sense, vaccines have become victims of their own success. Diseases that once induced fear and sparked desire for vaccines are now rare, and there is a false and dangerous sense of complacency among the public.
In addition, in recent years, growing numbers of persons have become hesitant about vaccines, fearing side effects and not appreciative of the enormous health and economic benefits that vaccines provide. A CDC report on 159 measles cases reported between January 4 and April 2, 2015, showed that 68 United States residents with measles were unvaccinated, and of these 29 (43%) cited philosophical or religious objections to vaccination (11). A 2014 national web-based poll of parents in the United States estimated that 90.8% (89.3–92.1%) reported accepting or planning to accept all recommended noninfluenza childhood vaccines, 5.6% (4.6–6.9%) reported intentionally delaying one or more, and 3.6% (2.8–4.5%) reported refusing one or more vaccines (12). A national survey of pediatricians in the United States reported that the proportion of pediatricians reporting parental vaccine refusals increased from 74.5% in 2006 to 87.0% in 2013 (13). A 67-country survey on the state of vaccine confidence reported an average of 5.8% of respondents globally were skeptical about the importance of vaccines, with that proportion rising to more than 15% in some countries (14). One of the major concerns in recent years has been the allegations that vaccines can cause autism. There are three major theories advanced on the role of vaccines in causing autism: (i) measles, mumps, rubella vaccine (MMR); (ii) thimerosal, an ethyl mercury containing preservative in many vaccines in the United States in the past, now mostly out of vaccines recommended for children; and (iii) too many vaccines (15). There have been multiple well-conducted studies and independent reviews of those studies by the Institute of Medicine (now the National Academy of Medicine) that do not support a role for vaccines in causing autism (16). Independent evaluation of the safety of the immunization schedule has found it to be extremely safe (17). However, translating the science into information capable of influencing vaccine skeptics has been difficult.
The National Vaccine Advisory Committee (NVAC) in the United States issued a report in 2015, with 23 recommendations to assure high levels of vaccine confidence (18). The recommendations have five focus areas: (i) measuring and tracking vaccine confidence, (ii) communication and community strategies to increase vaccine confidence, (iii) healthcare provider strategies to increase vaccine confidence, (iv) policy strategies to increase vaccine confidence, and (v) continued support and monitoring of the state of vaccine confidence. Critical to assuring confidence is evidence-based research to evaluate which interventions are most effective. The NVAC recommended that a repository of evidence-based best practices for informing, educating, and communicating with parents and others in ways that foster or increase vaccine confidence be created. And while we have focused on children, vaccine preventable diseases exact a substantial health burden in adults and immunization coverage rates for most recommended vaccines are substantially lower for adults than those achieved for recommended vaccines in children. Thus, there is need not only in enhancing immunization rates in children but also in adults.
In summary, vaccines are some of the most effective and also cost-effective prevention tools we have. But vaccines that are not administered to persons for whom they are recommended are not useful. It is incumbent upon all of us who work in the healthcare setting, as well as community leaders, to stress to our friends and colleagues the importance of vaccination both for the individual vaccinated as well as for the communities in which the individuals live. Also critically important, there remains an urgent need for greater emphasis on research to develop vaccines for global diseases for which vaccines either do not exist or need improvement.
[References and Acknowledgment at title link above]
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New England Journal of Medicine
April 13, 2017 Vol. 376 No. 15
http://www.nejm.org/toc/nejm/medical-journal
Perspective
Yellow Fever — Once Again on the Radar Screen in the Americas
Catharine I. Paules, M.D., and Anthony S. Fauci, M.D.
Four arthropod-borne viruses (arboviruses) have recently emerged or reemerged in the Americas, spreading rapidly through populations that had not previously been exposed to them and causing substantial morbidity and mortality.1 The first was dengue, which reemerged to cause widespread disease predominantly in South America and the Caribbean in the 1990s. This epidemic was followed by West Nile virus in 1999, which has since become endemic in the continental United States, and chikungunya in 2013, which continues to cause disease, predominantly in the Caribbean and South America. Most recently, Zika virus emerged in Brazil in 2015 and spread through infected travelers to more than 60 countries and territories in the Americas, including the United States.
Over the past several weeks, a fifth arbovirus, yellow fever virus, has broken out in Brazil, with the majority of the infections occurring in rural areas of the country. These are referred to as sylvatic, or jungle, cases, since the typical transmission cycle occurs between forest mosquitoes and forest-dwelling nonhuman primates, with humans serving only as incidental hosts. In this ongoing outbreak, health authorities have reported 234 confirmed infections and 80 confirmed deaths as of February 2017.2 Confirmed infections have occurred in the Brazilian states of Minas Gerais, Espírito Santo, and São Paulo (see map – Confirmed Cases of Yellow Fever in the Current Outbreak.), and hundreds of additional cases remain under investigation. The high number of cases is out of proportion to the number reported in a typical year in these areas.
Although there is currently no evidence that human-to-human transmission through Aedes aegypti mosquitoes (urban transmission) has occurred, the outbreak is affecting areas in close proximity to major urban centers where yellow fever vaccine is not routinely administered. This proximity raises concern that, for the first time in decades, urban transmission of yellow fever will occur in Brazil.
As we have seen with dengue, chikungunya, and Zika, A. aegypti–mediated arbovirus epidemics can move rapidly through populations with little preexisting immunity and spread more broadly owing to human travel. Although it is highly unlikely that we will see yellow fever outbreaks in the continental United States, where mosquito density is low and risk of exposure is limited, it is possible that travel-related cases of yellow fever could occur, with brief periods of local transmission in warmer regions such as the Gulf Coast states, where A. aegypti mosquitoes are prevalent.
It is also conceivable that yellow fever outbreaks may occur in the U.S. territories, just as the recent Zika epidemic reached Puerto Rico, causing a significant outbreak there and leading to thousands of travel-related cases and more than 250 locally transmitted cases in the continental United States. In an era of frequent international travel, any marked increase in domestic cases in Brazil raises the possibility of travel-related cases and local transmission in regions where yellow fever is not endemic. In light of the serious nature of this historically devastating disease, public health awareness and preparedness are critical, even for individual cases.
Yellow fever most likely originated in Africa and was imported into the Americas in the 1600s.3 It claimed hundreds of thousands of lives in the 18th and 19th centuries. The Philadelphia yellow fever epidemic of 1793, for example, killed approximately 10% of the city’s population and prompted the federal government to flee the city. In 1881, Cuban epidemiologist Carlos Finlay proposed that yellow fever was a mosquito-borne infection. The U.S. Army physician Walter Reed and a Yellow Fever Commission verified that fact in 1900. Subsequently, mosquito-control efforts and better sanitation practices virtually eliminated yellow fever from the United States and other nonendemic areas of the Americas, although sporadic outbreaks of varying magnitude continued to occur in tropical regions where the disease was endemic.4
In 1937, virologist Max Theiler developed a live attenuated yellow fever vaccine that is still in use today and that provides lifetime immunity in up to 99% of vaccinees, according to the World Health Organization (WHO). Extensive vaccination campaigns combined with effective vector-control strategies have significantly reduced the number of yellow fever cases worldwide. However, localized outbreaks continue to occur in parts of Africa and Central and South America, resulting in an estimated 84,000 to 170,000 severe cases and 29,000 to 60,000 related deaths per year, according to the WHO.
Beginning in December 2015, a large urban outbreak of yellow fever occurred in Angola and subsequently spread to the Democratic Republic of Congo, causing 961 confirmed cases and 137 deaths. In addition, cases related to travel from those countries were noted in nonendemic areas such as China, raising concern about international spread of disease. During the outbreak, the world’s emergency vaccine stockpile reserved for epidemic response was exhausted, prompting health authorities to immunize inhabitants of some areas using one fifth of the standard dose in order to extend the vaccine supply.5 Since vaccination is the mainstay of epidemic response, the limited number of stockpiled vaccine doses and the long time needed to produce additional vaccine made this outbreak difficult to control. To prevent a similar occurrence in Brazil or in future yellow fever outbreaks, early identification of cases and rapid implementation of public health management and prevention strategies, such as mosquito control and appropriate vaccination, are critical.
Early recognition may be difficult in countries such as the United States, where most physicians have never seen a case of yellow fever and know little about the clinical manifestations. Typically, yellow fever is suspected on the basis of clinical presentation and confirmed later, since definitive diagnosis requires testing available only in specialized laboratories. The clinical illness manifests in three stages: infection, remission, and intoxication.3 During the infection stage, patients present after a 3-to-6-day incubation period with a nonspecific febrile illness that is difficult to distinguish from other flulike diseases. High fevers associated with bradycardia, leukopenia, and transaminase elevations may provide a clue to the diagnosis, and patients will be viremic during this period.
This initial stage is followed by a period of remission, when clinical improvement occurs and most patients fully recover. However, 15 to 20% of patients have progression to the intoxication stage, in which symptoms recur after 24 to 48 hours.3 This stage is characterized by high fevers, hemorrhagic manifestations, severe hepatic dysfunction and jaundice (hence the name “yellow fever”), renal failure, cardiovascular abnormalities, central nervous system dysfunction, and shock. Antibodies may be detected during this stage; however, viremia has usually resolved. Case-fatality rates range from 20 to 60% in patients in whom severe disease develops, and treatment is supportive, since no antiviral therapies are currently available.3,4
Yellow fever is the most severe arbovirus ever to circulate in the Americas, and although vaccination campaigns and vector-control efforts have eliminated it from many areas, sylvatic transmission cycles continue to occur in endemic tropical regions. The most recent outbreak in Brazil highlights this phenomenon. If the current outbreak leads to urban spread through A. aegypti mosquitoes, clinicians should adopt a high index of suspicion for yellow fever, particularly in travelers returning from affected regions. As with all potentially reemerging infectious diseases, public health awareness and preparedness are essential to prevent a resurgence of this historical threat
vaccines and global health :: ethics and policy 