The authors of the paper define eradications as the “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.”

The paper presents a preliminary assessment of the eradicability of COVID-19 by comparing it with other worldwide diseases, including smallpox, which has been eradicated, and polio, for which just one of three serotypes persists.

Based on an established scoring system and additional technical, sociopolitical, and economic factors that the authors included, the study compiled a total of 17 variables relating to vaccine-preventable diseases, with a three-point relative scale for each variable. Each of the diseases received a score according to these metrics, with higher values indicating a greater chance of eradication.

COVID-19 scored as being slightly more eradicable than polio.

Smallpox was most eradicable with a score of 2.7. In comparison, COVID-19 scored 1.6, and polio scored 1.5.

Medical challenges

Dr. Robert Kim-Farley, MPH, of the University of California, Los Angeles’s Fielding School of Public Health — who was not involved in writing the article — told MNT: “The single greatest obstacle to true eradication will be achieving and sustaining the very high vaccination coverage (using a vaccine with no or extremely low infection breakthrough) needed to achieve full herd immunity, whereby transmission of COVID-19 in a community ceases.”

Although he is not giving up on achieving higher vaccination coverage through more robust international public health and social measures, Dr. Wilson said that herd immunity is not a requirement for eradication.

“Smallpox was eradicated without achieving herd immunity,” said Dr. Wilson, “but rather by targeted vaccination approaches. It is also notable that countries have also eliminated measles without (quite) achieving herd immunity, and, in fact, the whole of the Americas eliminated measles for a time.”

The paper notes that there is also a “risk of the persistence of the pandemic virus in non-human animal reservoirs,” a phenomenon that is occurring with COVID-19 in the U.S. and elsewhere.

Asked whether current animal reservoirs may doom an eradication effort, Dr. Wilson said we are not there yet.

“If we had the situation of influenza viruses (widespread in wild birds) then obviously eradication would not be feasible,” he noted.

He added that “it is possible to eradicate diseases in some wild animals — for example, eliminating rabies in wild foxes via aerial bait drops containing vaccine (as per Western Europe).”

Dr. Kim-Farley cited what he sees as the three most significant obstacles to eradication success.

Current vaccines, noted Dr. Kim-Farley, “although offering excellent protection against severe illness and death, still have some breakthrough infections that can infect others.”

Identifying cases of often-asymptomatic COVID-19 is also harder, said Dr. Kim-Farley, than it is with smallpox and measles, which “are usually always symptomatic and identifiable.”

Finally, there is “the lack of political will to apply (and the unwillingness of some persons to accept) the strict public health measures, such as required vaccination, required mask wearing, required quarantine and isolation, and required testing.”