Disease eradication campaigns
Disease eradication campaigns focus on completely eliminating specific infectious diseases from the world. True eradication is rare; smallpox is the only disease that has been fully eradicated to date. To be considered eradicated, a disease must no longer occur globally and no longer require control measures such as vaccinations. While many diseases can be controlled or eliminated to a manageable level, challenges such as inadequate public health infrastructure, lack of funding, and political will often hinder these efforts, particularly in developing countries.
Vaccination plays a crucial role in disease eradication, but successful campaigns depend not only on the availability of vaccines but also on the logistics of their distribution and administration. For instance, vaccines that require fewer doses and can be stored at room temperature are more effective in remote areas. Surveillance for new cases and maintaining adequate stockpiles of necessary treatments are also essential components of these campaigns.
Several diseases, such as guinea worm disease and poliomyelitis, are seen as potential candidates for future eradication, although each faces unique challenges. The ongoing efforts highlight the complexity of disease eradication and the importance of comprehensive strategies and global cooperation in public health initiatives.
Disease eradication campaigns
Definition
True eradication of an infectious disease is rare; in fact, only one infectious disease, smallpox, has been completely eradicated. While many other infectious diseases have been controlled to various degrees, for a disease to be considered totally eradicated, it must no longer be occurring anywhere in the world and must no longer require control measures, such as vaccination. Elimination of a disease means that the disease is still occurring, but at a very low and predictable level. Control of a disease means that organized plans and programs are in place for decreasing the number of new cases.
Vaccines
Vaccines are considered the best tools for eventual eradication of infectious diseases, but simply having a vaccine does not guarantee eradication or elimination of a disease. Vaccines to prevent some of the world’s most burdensome diseases have been available for decades, but a lack of public health programs, infrastructure, money, and political resolve have kept these vaccines from being as successful as hoped for in eradicating polio, measles, and other diseases, particularly in developing countries. To address this problem, the World Health Organization (WHO) and its partner agencies began the Expanded Program on Immunization in 1974 to increase the formerly abysmal rate of childhood vaccination in developing countries.
A vaccine that requires only one dose to induce immunity is more likely to be successful in eradicating disease than is a vaccine, such as the hepatitis B vaccine, that requires multiple doses, because fewer people will receive a complete immunization series. Vaccines that can be given at convenient times, particularly on the same schedule as other vaccines, are also more likely to aid in disease eradication than are those requiring an additional trip to a clinic. Also, vaccines that do not need precisely controlled storage conditions are easier to use in undeveloped areas than those that need to be kept frozen.
Other strategies are also important in the quest for disease eradication. Surveillance for new cases needs to be active and ongoing, at both local and global levels, so that small outbreaks can be controlled before they become large outbreaks. Sufficient stockpiles of drugs and vaccines must be available when needed.
Characteristics of the infectious agent and the disease itself can also impact the likelihood of eradication. For instance, a disease, such as smallpox, that becomes symptomatically obvious at the same time it becomes contagious will allow isolation of the infected person before he or she infects others. A virus, such as that which causes measles, can be contagious for days before symptoms appear, allowing the disease to spread to many contacts before the infection is recognized. Infectious agents that can live and reproduce in non-human animals or in insects will likely persist in those host organisms even after elimination from humans, making them difficult to eradicate.
Smallpox
Smallpox, caused by the variola virus, was a deadly contagious disease that killed 20 percent to 60 percent of those infected. Records of smallpox epidemics go back thousands of years, including records suggesting smallpox scars on the mummified body of the Egyptian pharaoh Ramses V, who died in 1157 BCE. The development of a vaccine in 1796, in which Edward Jenner used material from cowpox lesions to successfully inoculate against smallpox, led to a gradual decline in the disease. The last case of smallpox was seen in Somalia in 1977. WHO declared the disease eradicated in 1980.
Eradicable Diseases
Dracunculiasis, also referred to as guinea worm disease, will likely be the first parasitic disease eradicated. This painful and debilitating disease is acquired by drinking stagnant water containing worm larvae. Once swallowed by a human, the larvae mature, multiply, and migrate throughout the body, eventually eroding through the skin. They must be carefully and slowly pulled from the skin during a period of a month. Guinea worm disease has decreased from about four million cases in twenty countries in the late 1980s to fourteen cases in only four African countries in 2023. There is no drug that will cure the disease and no vaccination against it, so eradication efforts have concentrated on supplies of clean water and on educating people at risk about the need to filter drinking water.
Poliomyelitis too is considered an eradicable disease. The last large-scale outbreaks of polio in the United States occurred in the 1950s, and routine childhood immunization for this disease began after the development of an injectable vaccine in the 1950s and an oral vaccine in the 1960s. By 2002, polio remained in only a few countries, including Afghanistan, India, Pakistan, Egypt, and Nigeria. However, the number of cases has begun to climb, in part because of the decrease in the number of immunized children and young adults in Nigeria, where concern about the vaccine’s safety has derailed immunization efforts. Decreases in immunization pose risks everyowhere. In 2022, the United States reported its first case of polio in decades. The infection was reported in a 20-year-old unvaccinated man in New York. Increased numbers of polio cases are now also being reported in several countries, including many that border Nigeria. From 2022 to 2023, twenty-three countries reported cases of polio.
Impact
The Carter Center’s International Task Force for Disease Eradication considers several infectious diseases to be potentially eradicable in the future, but notes that there are impediments to success for each. Lymphatic filariasis eradication will require strengthening of health care systems in Africa. Eradication of measles could require development of a vaccine that can be given to infants before they are first exposed. The task force has categorized other infectious diseases as having the potential for elimination, but not for eradication, in limited geographical areas. These diseases include Chagas’ disease, hepatitis B, malaria, rabies, and onchocerciasis (river blindness).
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