Posts Tagged ‘vaccines’
By: Arielle Glatman Zaretsky, PhD
Throughout history, humans have sought to understand the human body and remedy ailments. Since the realization that disease can be caused by infection and the establishment of Koch’s postulates, designed to demonstrate that a specific microbe causes a disease, humans have sought to identify and “cure” diseases. However, while we have been successful as a species at developing treatments for numerous microbes, viruses, and even parasites, pure cures that prevent future reinfection have remained elusive. Indeed, the only human disease that has been eradicated in the modern era (smallpox) was eliminated through the successful development and application of preventative vaccines, not the implementation of any treatment strategy. Furthermore, the two next most likely candidates for eradication, dracunculiasis (guinea worm disease) and poliomyelitis (polio), are approaching this status through the use of preventative measures, via water filtration and vaccination, respectively. In fact, despite the recent pushback from a scientifically unfounded anti-vaxxers movement, the use of a standardized vaccination regimen has led to clear reductions in disease incidence of numerous childhood ailments in the Americas, including measles, mumps, rubella, and many others. Thus, although the development of antibiotics and other medical interventions have dramatically improved human health, vaccines remain the gold standard of preventative treatment for the potential of disease elimination. By Centers for Disease Control and Prevention [Public domain], via Wikimedia Commons
Recently, there have been numerous outbreaks of emerging or reemerging infectious diseases. From SARS to Ebola to Zika virus, these epidemics have led to significant morbidity and mortality, and have incited global panic. In the modern era of air travel and a global economy, disease can spread quickly across continents, making containment difficult. Additionally, the low incidence of these diseases means that few efforts are exerted to the development of treatments and interventions for them, and when these are attempted, the low incidence further complicates the implementation of clinical trials. For example, though Ebola has been a public health concern since the first outbreak in 1976, no successful Ebola treatment or vaccine existed until the most recent outbreak of 2014-2016. This outbreak resulted in the deaths of more than 11,000 people, spread across more than 4 countries, and motivated the development of several treatments and 2 vaccine candidates, which have now reached human trials. However, these treatments currently remain unlicensed and are still undergoing testing, and were not available at the start or even the height of the outbreak when they were most needed. Instead, diseases that occur primarily in low income populations in developing countries are understudied, for lack of financial incentive. Thus, these pathogens can persist at low levels in populations, particularly in developing countries, creating a high likelihood of eventual outbreak and potential for future epidemics.
This stream of newly emerging diseases and the re-emergence of previously untreatable diseases brings the question of how to address these outbreaks and prevent global pandemics to the forefront for public health policy makers and agencies tasked with controlling infectious disease spread. Indeed, many regulatory bodies have integrated accelerated approval policies that can be implemented in an outbreak to hasten the bench to bedside process. Although the tools to identify new pathogens rapidly during an outbreak have advanced tremendously, the pathway from identification to treatment or prevention remains complicated. Regulatory and bureaucratic delays compound the slow and complicated research processes, and the ability to conduct clinical trials can be hindered by rare exposures to these pathogens. Thus, the World Health Organization (WHO) has compiled a blueprint for the prevention of future epidemics, meant to inspire partnerships in the development of tools, techniques, medications and approaches to reduce the frequency and severity of these disease outbreaks. Through the documentation and public declaration of disease priorities and approaches to promote research and development in these disease areas, WHO has set up a new phase of epidemic prevention through proactive research and strategy.
Recently, this inspired the establishment of the Coalition for Epidemic Preparedness Innovations (CEPI) by a mixed group of public and private funding organizations, including the Bill and Melinda Gates Foundation, inspired by the suggestion that an Ebola vaccine could have prevented the recent outbreak if not for the lack of funding slowing research and development, to begin to create a pipeline for developing solutions to control and contain outbreaks, thereby preventing epidemics. Instead of focusing on developing treatments to ongoing outbreaks, the mission at CEPI is to identify likely candidates for future outbreaks based on known epidemic threats and to lower the barriers for effective vaccine development through assisting with initial dose and safety trials, and providing support through both the research and clinical trials, and the regulatory and industry aspects. If successful, this approach could lead to a stockpile of ready-made vaccines, which could easily be deployed to sites of an outbreak and administered to aid workers to reduce their morality and improve containment. What makes this coalition both unique and exciting is the commitment to orphan vaccines, so called for their lack of financial appeal to the pharmaceutical industry that normally determines the research and development priorities, and the prioritization of vaccine development over treatment or other prophylactic approaches. The advantage of a vaccination strategy is that it prevents disease through one simple treatment, with numerous precedents for adaptation of the vaccine to a form that is permissive of the potential temperature fluctuations and shipping difficulties likely to arise in developing regions. Furthermore, it aids in containment, by preventing infection, and can be quickly administered to large at risk populations.
Thus, while the recent outbreaks have incited fear, there is reason for hope. Indeed, the realization of these vaccination approaches and improved fast tracking of planning and regulatory processes could have long reaching advantages for endemic countries, as well as global health and epidemic prevention.
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By: Jessica Hostetler, PhD
The world made some good progress recently toward controlling or eliminating several diseases. Such gains are often long and hard fought. Vaccines are often a primary tool for eliminating diseases, which makes the rise in vaccine scepticism in many developed nations all the more troubling and fears of disease resurgences and outbreaks all too real.
The good news for disease control started in July with the commendation from the World Health Organization (WHO) to India for its work in eliminating yaws earlier in May of 2016. Yaws, often described as a “forgotten disease,” is a chronic skin disease caused by the bacterium Treponema pallidum, which is closely related to the organism that causes syphilis. It affects primarily children in poverty-stricken, crowded communities in about 13 countries with limited access to clean water, sanitation, and healthcare and can lead to severe disfigurement if not treated. Yaws is treated by a single dose of oral (Azithromycin) or injected (Benzathine penicillin) antibiotic. India tackled yaws through a campaign spanning years. “Highly targeted awareness and early treatment campaigns in vulnerable communities enabled treatment of yaws cases and interruption of disease transmission,” said Dr. Khetrapal Singh, the WHO Regional Director for South-East Asia in a WHO July press release. The success in India as the first country to eliminate yaws under the 2012 WHO neglected tropical diseases (NTD) roadmap gives renewed momentum toward global eradication in the remaining yaws-endemic countries by 2020.
More good news followed on September 5th with the announcement from WHO that Sri Lanka is now free of malaria. It is a large turnaround from the historical burden of the disease which was as high as 5 million cases per year in the 1930’s followed by a highly successful elimination program resulting in only 17 recorded cases in 1963. However, due to multiple factors, potentially including “human migrations, asymptomatic parasite-carriers, vector-reintroduction, behavioural changes in the vector and the emergence of drug and insecticide resistance,” cases soared again to half a million or more cases per year in the 1970s and 1980s. With a renewed focus on global malaria elimination in the 2000s, Sri Lanka has become a remarkable success story. As laid out in the WHO September press release, Sri Lanka’s strategy for elimination included targeting the parasites and the mosquitoes transmitting them through “mobile malaria clinics in high transmission areas” to give “prompt and effective treatment,” which reduced disease transmission and the parasite reservoir. Work such as this requires large teams of people for “effective surveillance, community engagement and health education.” But given Sri Lanka’s proximity to India, where malaria is still endemic, active surveillance for newly introduced cases will be essential to keep the disease at bay.
On September 27th, 2016, the Pan American Health Organization (PAHO) certified that the region of the Americas is free from endemic measles. This news isn’t strictly “new” as the last locally transmitted case of measles in the Americas occurred in Venezuela in 2002. Certification as being disease-free is a long process, however, and the Americas continued to experience over 5000 imported measles cases between 2003 and 2014, necessitating careful documentation to ensure local transmission had ended. Measles is a highly contagious virus and causes fever and a characteristic rash. It can lead to severe symptoms including “pneumonia, brain swelling and even death.” This is a historical success, but the WHO reports that measles still caused over 100,000 deaths globally, mostly children, in 2014. Continued vigilance and worldwide vaccination compliance are needed to maintain gains and reduce the disease where it still spreads endemically.
Such good news represents decades of hard work from international organizations, national governments and NGOs and many field workers on the ground. These efforts represent the best of humanity in working to alleviate suffering and eradicate disease. One of the primary tools in the fight against infectious diseases remains the development and mass administration of vaccines. In the US, vaccination skepticism has been growing for years on the heels of a now-retracted study in The Lancet in 1998 that proposed a link between the Measles-Mumps-Rubella (MMR) vaccine and the development of autism. While there is no evidence that vaccinations or vaccine ingredients cause autism in any way, the paper caused lasting damage to the public perception of vaccinations. A recent study examining American Academy of Pediatrics Periodic Surveys from 2006 and 2013 reports that while most parents no longer cite autism as a reason for avoiding vaccines for their children, many are now avoiding vaccinations because they are “unnecessary.” An increasing number of pediatricians (up from 6% in 2006 to 11% in 2013) report always dismissing patients for “continued vaccine refusal” citing both a lack of trust in the physician-patient relationship and concern for other patients as primary reasons. Non-compliance with vaccinations is largely viewed as the driver behind an outbreak of measles in and around the Disneyland resort in California in 2014-2015 as 67% of those with infections (who were vaccine eligible) “were intentionally unvaccinated because of personal beliefs.” Vaccination rates in some California communities had fallen below the level required for protection of the population; this spurred a controversial tightening of regulations requiring vaccinations for all public-school educated children with no exemption for religious or personal beliefs.
The international news is even more concerning with a recent global survey (with a commentary in Science) looking at attitudes toward vaccination showing that 41% of respondents from France and 31% of respondents from Japan disagreed with the statement that vaccines are safe. Russia had the highest scepticism about the importance of vaccines at 17%. The survey notes that “Countries with high levels of schooling and good access to health services are associated with lower rates of positive sentiment, pointing to an emerging inverse relationship between vaccine sentiments and socio-economic status.” The WHO reports that vaccines prevent 2-3 million deaths per year from diphtheria, tetanus, pertussis (whooping cough), and measles, but that as many as 1.5 million children under the age of 5 died from vaccine-preventable diseases in 2008. Vaccine-scepticism and outbreaks from vaccine non-compliance represent an alarming and avoidable threat as we aim to eliminate vaccine-preventable diseases from the world. As a perspective by Dr. Douglas S. Diekema in the New England Journal of Medicine notes, we must set a high goal in the US and globally to improve childhood vaccination rates through increased and free access to vaccines, but also swift rebuttals of unbalanced or incorrect reporting on vaccinations. The physician-patient relationship may offer the best opportunity to educate and “influence the vaccine-hesitant.”
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