The global eradication of Covid-19 is more feasible than polio, but less so than smallpox, public health experts have said – but such success requires a high vaccine uptake and a swift response to new variants.

The call comes off the back of a study published in the online journal BMJ Global Health, which looked at the comparative scores of the technical, sociopolitical and economic factors relevant for all three infections.

The report’s authors – Professor Nick Wilson and Professor Michael Baker of the University of Otago, Wellington, New Zealand – argued that vaccination, public health measures and a global interest in ending the pandemic all made eradication possible – but acknowledged considerable challenges remain when it comes to ensuring a sufficient number of people are suitably vaccinated or in tackling rapidly-evolving new variants.

Eradicating Covid-19 more feasible than polio

To determine the feasibility of eradicating Covid-19, the authors used a three-point scoring system set against 17 variables which could be seen in two comparative diseases – smallpox and polio. These variables included factors such as the availability of a safe and effective vaccine; lifelong immunity; impact of public health measures; effective government management of infection control messaging; political and public concern about the economic and social impacts of the infection; and public acceptance of infection control measures.

The average (total) scores in the analysis added up to 2.7 (43/48) for smallpox, 1.6 (28/51) for Covid-19, and 1.5 (26/51) for polio.

The authors said: “While our analysis is a preliminary effort, with various subjective components, it does seem to put COVID-19 eradicability into the realms of being possible, especially in terms of technical feasibility.

“Nevertheless, there are of course limits to viral evolution, so we can expect the virus to eventually reach peak fitness, and new vaccines can be formulated.

“Other challenges would be the high upfront costs (for vaccination and upgrading health systems) and achieving the necessary international cooperation in the face of ‘vaccine nationalism’ and government-mediated ‘anti-science aggression’.”

Upgrades to health systems to tackle the virus could also aid in the control of other conditions

However, despite these challenges, there is “unprecedented global interest in disease control and massive investment in vaccination against the pandemic,” they point out. Additionally, public health measures such as border controls, social distancing, contact tracing and mask wearing have been enormously effective, with smallpox and polio not benefitting from the same level of public health involvement.

The authors also claim that upgrades to health systems to tackle the virus could also aid in the control of other conditions, such as measles. “Collectively these factors might mean that an ‘expected value’ analysis could ultimately estimate that the benefits outweigh the costs, even if eradication takes many years and has a significant risk of failure,” they said.

The authors acknowledge that their study is preliminary, and more extensive in-depth work is required. Additionally, the say that World Health Organization – or a coalition of national-level agencies working collaboratively – would need to formally review the feasibility and desirability of attempting Covid-19 eradication.