Coronavirus eradication in the 'realms of being possible', experts say

Global eradication of the coronavirus is in the "realms of being possible", according to public health experts.

Since the infection was identified at the end of 2019, more than 202 million cases have been confirmed worldwide, and it has killed over 4 million people.

The administration of 4.4 billion vaccine doses offers hope for the future. Nevertheless, the emergence of new variants and concerns over waning immunity has dampened enthusiasm.

Writing in the BMJ Global Health, scientists from the University of Otago, Wellington, said the eradication of the coronavirus is "more feasible" than it is for polio "but much less so than for smallpox", which was officially wiped out in 1980.

Read more: Severe coronavirus accelerates Alzheimer's

The team has stressed their analysis is "very preliminary", with eradication potentially taking "many years". Nevertheless, sustained eradication has been achieved for long periods of time in China, Hong Kong, Iceland and New Zealand, raising hope it could one day be possible on a global scale.

On a global scale, the rollout of the coronavirus vaccines has been patchy.

Nevertheless, the unprecedented immunisation programme, combined with public health measures like face coverings and social distancing, makes global eradication "possible", according to the Otago scientists.

Achieving a high vaccine coverage, while responding to new variants that could bypass immunity, remains the biggest challenges.

Read more: Coronavirus particles in retina of three COVID victims

To estimate the feasibility of eradication, the Otago scientists compared the coronavirus with two other viruses that have or once had vaccines – smallpox and polio, the latter of which has been eradicated for two out of three of its strains.

"Is COVID-19 [the disease caused by the coronavirus] also potentially eradicable or is it inevitably endemic having established itself across the world?" wrote the scientists.

"Commentators have focused on the challenges of reaching population [herd] immunity, yet population immunity is not essential and was not achieved for smallpox, which was eradicated through ring vaccination [immunising those who are most likely to be infected]."

To learn more, the scientists looked at 17 factors that may influence eradication, defined as "the permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts".

These included the availability of a safe and effective vaccine, the likelihood of lifelong immunity and public acceptance of infection control measures.

"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," wrote the scientists.

Poor vaccine acceptance may be more of an issue with the coronavirus than polio or smallpox, based on some people's mistaken belief that its immunisation programme was rushed.

More transmissible variants that evade immunity may also outrun the vaccines' rollouts.

Read more: Severe coronavirus could trigger diabetes

"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," wrote the scientists.

"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'."

The coronavirus may also persist in animal reservoirs, but this is not expected to be a serious issue.

Although it is unclear how the pandemic originated, the coronavirus is thought to have "jumped" from bats into humans, possibly via pangolins. Outbreaks have occurred on mink farms, and these "could potentially be controlled by quarantining and culling".

Coronavirus vaccines are now being developed for domestic animals, an approach that helped eradicate rinderpest, a famine-causing cattle disease. An oral vaccine has also regionally eliminated rabies in wild foxes.

Overall, the extraordinary health, economic and social impacts of the coronavirus have generated an "unprecedented global interest in disease control and massive investment in vaccination against the pandemic".

Out of the three viruses the scientists studied, the coronavirus may be particularly dampened by border controls, social distancing, contact tracing and face coverings.

Upgrading healthcare systems in response to the pandemic could also ease other infections, like measles, which is considered a "leading contender" for an infection's eradication.

In 2017, the World Health Organization declared the UK had "eliminated measles" based on 2014/16 data. This was reversed when 989 confirmed cases came to light in England and Wales in 2018.

Speaking of the coronavirus, the Otago scientists concluded: "Collectively these factors might mean 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."

Watch: Do coronavirus vaccines affect fertility?