The lives of 122 million children under the age of five have been saved over the past 25 years. Vaccines were "the single biggest reason for the drop", philanthropists Bill and Melinda Gates recently wrote in a letter to investing guru Warren Buffett, who donated $37 billion to their foundation a little over a decade ago. The couple hope to more than halve the number of childhood deaths to below 3 million by 2030, but Donald Trump threatens to hold them back.
The basic package of childhood vaccines is available to 86% of children around the world, say the Microsoft founder and his wife, and the coverage gap between rich and developing countries is narrower than ever before. The pair add that the pentavalent vaccine, which "protects against five deadly infections in a single shot", now costs less than a dollar to produce. And Bill Gates points out that every dollar spent on childhood immunisation generates $44 in economic benefits. They hope to eradicate malaria, HIV, tuberculosis and polio within their lifetimes.
Elsewhere, they explain why vaccines aren't available where they're needed: the families in need can't afford them, meaning there are no market incentives to produce them. The couple have tackled the problem by partnering with businesses and governments to set up Gavi, a Vaccine Alliance that connects vaccine-development companies with wealthy governments for funding, as well as poor countries that can help deliver the vaccines to their citizens. Gavi has helped to immunise 580 million children around the world since 2000, but 19 million - many of whom live in conflict zones or remote areas - are still not fully immunised.
Bill and Melinda Gates haven't shied away from criticising the new US president. They decried his reinstatement of the Mexico City Policy, which cuts off US foreign aid to any non-governmental organisation abroad that provides or even discusses abortion as a family-planning option. "We’re concerned that this shift could impact millions of women and girls around the world," Melinda Gates told The Guardian, while her husband warned that turning off the tap could “create a void that even a foundation like ours can’t fill”.
Another challenge could be around the corner. Trump has shown support for the 'anti-vaxxer' movement, a group that believes vaccines received during childhood can lead to autism. He has repeatedly claimed that "massive" shots of multiple vaccines cause autism, describing them as "doctor-inflicted autism" and claiming there are "many such cases". Last year he met with Andrew Wakefield, a physician who claimed to have proved measles-mumps-rubella (MMR) immunisation caused autism, but whose study was retracted from the Lancet medical journal after it was found to be false. Wakefield later alleged the mercury-based chemical thimerosal - which ceased being used in vaccines for children in the early 2000s - caused autism, but medical authorities rejected that claim too.
Moreover, Trump invited leading anti-vaxxer Robert F. Kennedy Jr. to Trump Tower in January; the conspiracy theorist claimed afterward that the president had invited him to chair a commission on vaccine safety. And during a recent meeting with educators, the president suggested there has been a "tremendous increase" in the number of autistic children and said "maybe we can do something". In fact, most experts attribute the slight increase to greater awareness, reduced stigma and broader diagnostic criteria.
Melinda Gates dismissed anti-vaxxer claims last year, arguing Americans take vaccines "for granted" and African women "will walk 10 kilometers in the heat with their child and line up to get a vaccine" because they've seen children die without them. But they shouldn't be ignored: Trump can cause immense damage if he decides to gut funding for vaccines. Even redirecting funds towards pointless scientific research and inquiries on the subject would be frustrating when there are higher priorities. For instance, a national prevalence survey of autism has never been conducted.
Given Trump's penchant for favouring anecdotes over science or facts, it's unlikely he will change his mind about the risks of vaccines. And given his track record of backing up wrong-headed beliefs with equally uninformed policies, efforts to vaccinate the world's children will face significant setbacks. Good luck, Bill and Melinda.