Despite appearing to be synonymous verbs, in the world of vaccines, elimination and eradication have a different meaning. Eradicating is forever, while eliminating implies the possibility of reversal. A virus may acquire the status of eliminated in one country or region but will not be considered eradicated as long as it circulates elsewhere.
Smallpox, a disease caused by the Variola viruses, was officially declared eradicated in 1980. It represents an exceptional collective success story in the fight against infection. The disease frequently involved a slow death with great suffering. Smallpox vaccination campaigns, the oldest in the world, ceased with the virus.
Is this not the ultimate goal of vaccinology – to vaccinate in order to stop vaccinating, if possible?
Smallpox is the only human viral disease eradicated by science and medicine. I would like to add that it was also thanks to those authorities, fathers, and mothers who trusted medicine, and also, by omission, to those people who did not even think about it. In 1984 the British virologist Stuart-Harris (1909-1996) predicted that the next two viruses to be listed as eradicated would be polio and measles. But more than thirty years have passed and the proposed dates for the eradication of these viruses are periodically renewed, one defeat after another.
«The proposed dates for the eradication of polio and measles are periodically renewed, one defeat after another»
Not every virus can be eradicated. For a human infectious disease to disappear, a number of conditions must be met: the disease must manifest itself with clear symptoms; the infectious agent must not have any breeding grounds or reservoirs in other species; it must not be transmitted by vectors, such as mosquitoes; it must not have any inactivity or latency periods; there must exist the possibility of preventing transmission with an effective vaccine; and, most importantly, vaccination coverage must be high, i.e., a high proportion of all vaccinable individuals must be vaccinated.
Stuart-Harris’s optimism in the 1980s was by no means unfounded. Today, the growing number of countries that have eliminated the infection still allows us to pursue the dream of eradicating polio. For measles, expectations are unfortunately pessimistic. The disease is advancing because vaccine coverage is falling. The virus has recently lost its elimination status in the United Kingdom, Greece, the Czech Republic, and Albania.
High vaccine coverage is encountering an unexpected obstacle. Recent evidence suggests that anti-vaccination attitudes and concerns are, so to speak, infecting some communities’ health care workers,1 who are still the most trusted by parents when it comes to vaccines. I am speaking in general, and therefore imprecise, terms. The attitude towards each vaccine has its own specificities.
Thus, the engine of eradication — of vaccinating to, potentially, be able to stop vaccinating — is beginning to break down at a key point where the knowledge, perspective, and trust in vaccines of the healthcare community consistently reinforced effective vaccine coverage in the past. The lack of sufficient vaccine coverage condemns the attainable goal of eradication and, paradoxically, promotes longer and more intensive vaccination campaigns.
Forgive the platitude: vaccination prevents illness and premature death; non-vaccination simply does not.
1. See: European Centre for Decease Prevention and Control. (2015). Vaccine hesitancy among healthcare workers and their patients in Europe: A qualitative study. Stockholm: ECDC.; and also: Picchio, C. A., García Carrasco, M., Sagué Vilavella, M., & Rius, C. (2019). Knowledge, attitudes and beliefs about vaccination in primary healthcare workers involved in the administration of systematic childhood vaccines, Barcelona, 2016/17. Euro Surveill, 24(6), 1800117. doi: 10.2807/1560-7917.ES.2019.24.6.1800117 (Go back)