Disease Elimination and Eradication
What is disease elimination?
Elimination of disease:
Reduction to zero of the incidence of a specified disease in a defined geographical area as a result of deliberate efforts; continued intervention measures are required. Example: elimination of wild polio in Nigeria.
Elimination of infections:
Reduction to zero of the incidence of infection caused by a specific agent in a defined geographical area as a result of deliberate efforts; continued measures to prevent re-establishment of transmission are required. Infections can be reintroduced as long as the disease is present in other parts of the world. Example: measles, poliomyelitis in the Americas.
What is disease eradication?
Permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts; intervention measures are no longer needed. Example: smallpox.
What diseases have been eradicated?
Smallpox is the only human disease to have been eradicated in the history of public health. Thanks to the discovery of the smallpox vaccine in 1796, the World Health Organization declared smallpox eradicated in 1980 – almost two centuries after the vaccine was first developed. Now that the disease has been eradicated, routine vaccination has stopped, but surveillance is ongoing. Other human diseases on the cusp of eradication are polio and guinea worm disease. The only other disease to have been eradicated is rinderpest, which was a deadly disease that affected cattle.
In order to assess if a disease can be determined, scientists and public health officials consider a set of criteria:
- Is the disease easily diagnosable or recognizable?
- Is there a non-human reservoir or vector (or both)?
- Is the disease geographically restricted?
- Is there a vaccine?
- Are there other transmission-disrupting alternatives to a vaccine?
In addition to these scientific criteria, sufficient global political and economic coordination is necessary, supported by awareness and education campaigns to increase support among the public.
The ongoing process of disease elimination and eradication
Two diseases that are slated for eradication are polio and guinea worm, while the elimination of 20 neglected tropical diseases (NTDs) is a global target set by WHO in the recently adopted 2021-2030 Roadmap.
Challenges of disease elimination
The last mile of disease elimination and eradication is often the hardest, requiring concentrated efforts and resources – both human and financial – to close the remaining gap. Political and community engagement and commitment is required to achieve global targets, and to ensure that competing priorities do not detract from the end game.