With the possible exception of antibiotics, no medical procedure has saved more lives than vaccination. Yet getting vaccines into the arms of those most at risk of disease, debility and death has rarely been straightforward or easy.

Take the video that went viral in early August, showing six Peruvian health workers ascending a sheer mountain trail in the Andes with a cold storage box packed with coronavirus vaccines. To judge by the grainy images, the box is too large to be hoisted onto their shoulders, and in this precipitous mist-shrouded region airlifts are clearly out of the question. Instead, they are shown crouching under the strain of their life-saving cargo, as they inch the crate slowly up a treacherous, rock-strewn path. It takes 15 hours for them to reach their destination, high in the Ayacucho region of the Andes, after which they must descend to the foot of the mountain and start the process all over again.

In a striking historical coincidence, British botanists in the 1860s, sponsored by the India Office, journeyed along similar Andean trails in search of “Peruvian bark” – for centuries, the only source of the valuable antimalarial quinine. Motivated by the humanitarian desire to supply the world with a cure for the mosquito-borne disease, by 1872 the India Office had four million bark trees under cultivation in British India and was manufacturing a cheap malaria treatment that retailed for just a rupee an ounce.

Today, the world is desperately in need of a similar philanthropic effort to end the vaccine divide that has seen populations in the Global South – such as the indigenous descendants of the Inca in Peru – struggling to obtain life-saving coronavirus vaccines, while countries in the Global North sit on stockpiles that are nearing their expiry date or which, because of stubborn pockets of vaccine resistance, may never be utilised.

In Westminster and Camden, for instance, one in three adults have yet to present themselves for their first jab; this, despite the fact that across the UK, 75 per cent of the population has been double jabbed. By contrast, in Peru, which has the highest per capita death rate in the world from Covid-19, only 11 per cent of the country’s 32.5 million people have been fully immunised against the coronavirus.

This is not only a problem for Peru, but for the world. 80 per cent of Covid-19 infections in Peru are due to the Lambda variant – which, studies suggest, may be as infectious as Delta. Worse, a recent pre-print article by researchers at the University of Tokyo indicates that Lambda may also be capable of evading the neutralising antibodies induced by Coronavac, a vaccine manufactured by the Chinese company Sinovac that has been widely distributed in both Chile and Peru.

Much research on this variant remains to be done – urgently. So far, there is no evidence that Coronavac or other vaccines are seriously ineffective against the Lambda or other variants, but the possibility must now be seriously investigated. Indeed, in a recent assessment, SAGE, the scientific body that advises the UK government, said it was “almost certain” that the accumulation of genetic changes in circulating viruses would eventually result in a case of vaccine escape – hence the importance of distributing sufficient vaccines to immunise everyone in the world as rapidly as possible; what Tortoise has rightly called #TheArmsRace.

Yet while the World Health Organization estimates that 11 billion jabs are needed to vaccinate everyone on the globe, the G7 has so far pledged just one billion to low- and middle-income countries. Bear in mind that 13 countries, including the US and the UK, have already ordered sufficient doses to vaccinate their entire populations, plus all of the world’s vulnerable groups, combined. 

The choice is stark. According to a report by the Global Health Security Consortium, if Britain and other “vaccine-rich” countries were to share their doses more equitably, eliminate hoarding vaccines, and scale up the measures required to deliver them to hard-to-reach populations then all the world’s priority adults could be fully vaccinated by the end of 2021.

The point cannot be made too often, because – to be frank – the message has yet to get through to the governments and peoples of the wealthier nations. This is not only the philanthropic thing to do; it is also manifestly in our self-interest. Based on the reproduction number of the original coronavirus, it used to be thought that herd immunity would kick in when 70 per cent of a population had been fully immunised. According to the Financial Times’ Covid-19 vaccine tracker, several countries, including Malta, have already reached or are close to reaching that threshold. But because Delta, currently the dominant variant in most of the world, is five to six times more infectious than the original version of the virus, it is probable that in excess of 80 per cent of a population will now need to be vaccinated in order to reach the Elysian fields of herd immunity. 

Let us go a step further: if the coronavirus were to mutate to become as infectious as measles – which has a reproduction number of 12 – then in excess of 95 per cent would need to be vaccinated. And please note: this does not take into account the extent to which vaccination is a barrier against transmissibility, or whether the new variants can be passed on by individuals who have received both jabs but do not themselves suffer symptoms. What of herd immunity in those circumstances? Again, more research is needed.

The nightmare scenario, however, is the emergence of a strain resistant to current vaccines, or one with a similar fatality rate to MERS, the coronavirus first identified in Saudi Arabia in 2012, which is deadly in around a third of cases. Given that the coronavirus currently has an infection-fatality ratio of around 1 per cent, some geneticists consider that scenario “extraordinarily implausible”. The coronavirus could just as easily mutate so as to become milder, like the common cold, they say. Nonetheless, the nightmare scenario cannot be ruled out. Nor can Britons be sure of being able to safely resume foreign travel until everyone in the world enjoys similar immunisation levels to the Maltese.

Unfortunately, the UK and other G7 nations – instead of collaborating with genuine urgency to get jabs in arms in the poorer nations – are using their superior spending power to foster what Oxfam has called a system of “vaccine apartheid”. According to the life science analytics company Airfinity, the UK will shortly be sitting on a surplus of 210 million vaccines – even allowing for boosters being administered to the most vulnerable groups this autumn.

This imbalance will come as no surprise to anthropologists who have long argued that humanitarian interventions, particularly in the field of health, entail what the French sociologist Didier Fassin calls a “politics of life”. Although the stated object of such interventions is to save lives, in practice it is not possible to treat all lives equally. Instead, all such initiatives invariably involve what Fassin calls “making a selection of which existences it is possible or legitimate to save”.

Though all global efforts to contain or eradicate infectious diseases naturally draw on the rhetoric of medical humanitarianism – and in the past, the Rockefeller, Gates and other philanthropic organisations have funded the elimination of hookworm, yellow fever, malaria and polio – the historical record suggests that, on the whole, such campaigns only succeed where disease control also coincides with the economic and/or geopolitical interests of wealthy nations.

The classic example is smallpox. Ever since the English physician Edward Jenner discovered in 1796 that he was able to induce immunity against smallpox by injecting individuals with material from the related cowpox virus, it has been known that vaccination could eradicate the disease. This is because, unlike the coronavirus, there is no animal reservoir for smallpox – so once it has been eradicated in humans it has been eradicated everywhere. This milestone was reached in 1977 when, after a decade-long campaign, the WHO announced it had identified the last naturally occurring case of smallpox in Somalia (three years later, the WHO officially announced it had eradicated the disease).

However, eradication was never a foregone conclusion – largely because smallpox vaccination was itself controversial and, as with the coronavirus today, some sections of the population were reluctant to be immunised. This was not only the case in Bangladesh, where WHO vaccination teams employed strong-arm tactics to hunt down and vaccinate individuals suspected of harbouring smallpox, but in cities in developed countries. 

For instance: in the 1880s, Leicester became a hotbed of anti-vax sentiment and the site of rioting as parents rebelled against legislation that sought to compel them to vaccinate their children. The US was even more resistant to the practice, and, by the 1920s, vaccination rates in some rural areas were as low as 10 per cent.

Even so, thanks to a combination of vaccination, better sanitation, and the isolation and quarantining of suspected cases and their contacts – a method pioneered in Leicester (precisely because of the strong opposition to vaccination there) and later exported worldwide – incidence of smallpox had declined by the late 1940s to such an extent in Europe and North America that the leading industrial nations were engaged in essentially defensive policies designed to keep smallpox out by policing their borders. In 1947, however, the fragility of this approach was starkly exposed when a man travelling from Mexico City to New York fell ill and died in hospital – sparking a rush by New Yorkers to get vaccinated.

By the 1950s, the US was spending $15-20 million a year on defence against a disease that had not afflicted the country for a decade and a half, and had reached what the historian of science Nancy Leys Stepan rightly calls “a tipping point”. The US grasped that, rather than continually vaccinating its own population, it would be cheaper and more effective to try to eradicate smallpox outside its borders, and agreed to fund the global battle against the disease. 

Thus it was that, between 1967 and 1979, the US stumped up $32 million for the WHO’s global anti-smallpox drive, with international donors providing a further $98 million under an international burden-sharing arrangement. Some global health experts, such as Jeremy Farrar, the director of the Wellcome Trust and a member of SAGE, and the UK’s former prime minister Gordon Brown, think that a similar burden-sharing formula is exactly what is needed now. “The richest countries [should be] paying the most”, writes Farrar in his book Spike: The Virus Versus the People (co-authored with Anjana Ahuja), “not only because they have the broadest shoulders but also because they will benefit most when trade and travel resume”.

In this spirit, the 2014-2016 Ebola epidemic prompted the United Nations to take charge of the international humanitarian and medical relief effort, with the US Congress agreeing to emergency aid of $5.4 billion for the five worst-hit countries in West Africa. Compare and contrast the response in 2019, when the whole world was faced with the far graver crisis of a coronavirus pandemic. Only $8 billion was forthcoming in pledges for the WHO’s vaccine-purchasing facility, COVAX – $2 billion of which have yet to be received.

And even the full amount is only sufficient to immunise 20 per cent of the populations of low- and middle-income countries. To purchase enough vaccines to immunise 70 per cent of those populations – and have a chance of reaching herd immunity – around $50 billion is needed. As Farrar puts it: “Crumbs from the table will not cut it in an era of pandemics”.

We should be mindful of the lessons of history. In 2019, the last year for which figures are available, there were 229 million cases of malaria worldwide and an estimated 409,000 deaths. We have known about the curative powers of Peruvian bark since the 17th Century, and the cheap quinine substitute, chloroquine, has been widely available since 1950. However, many strains of the malaria parasite are now resistant to it.

To date, only one malaria vaccine has been licensed for use in children and only one, still in the trial stage, has demonstrated in excess of 75 per cent efficacy – a requirement for licensure under the WHO’s Malaria Vaccine Technology Roadmap. But every year nearly 20 million children go without already licensed vaccines for diseases such as diphtheria, tetanus, pertussis and measles. And of course, they and their parents and older siblings are also as susceptible to Covid as anyone else. Where should they come in the calculus of humanitarian interventions?

Let us candidly admit that, in practice, we cannot afford to treat all the world’s ills and that, inevitably, choices must be made. Even with that practical caveat in mind, it is surely in our interests to ensure that the indigenous peoples of the Andes have access to the same coronavirus vaccines as populations in the Global North. And what is true of South America is even more so in sub-Saharan Africa where the prevalence of HIV and other diseases seriously increases the risk of Covid mutations in immune-compromised individuals – mutations that may result in the emergence of vaccine-resistant variants.

Unlike smallpox, it is impossible to eradicate the coronavirus – it could re-emerge from a bat or some other animal reservoir at any time, and SAGE has already warned that the virus may jump back and forth between species. But, as in the 1950s, we are now at a tipping point where it makes more sense, on medical and economic grounds, for wealthy countries to redistribute surplus doses to those in the world most in need of protection – and to do so with all possible urgency. That this also happens to be the most compassionate and humanitarian course of action should only strengthen that sense of mission.

Photograph by Diego Ramos/AFP via Getty Images

Mark Honigsbaum is a medical historian and author of The Pandemic Century: A History of Global Contagion from the Spanish Flu to Covid-19 (WH Allen, 2020)