Those of us fortunate enough to live in the western world should thank our lucky stars. Diseases such as diphtheria and pertussis sound, to our privileged ears, like relics from a bygone era. In rich countries (and many poorer ones) these scourges of humanity have been seen off by vaccines, a miracle of modern medicine that we now take for granted. But for many diseases, particularly those endemic to the tropics, no vaccines exist for illnesses that bring misery to millions. So it’s heartening news that an Ebola vaccine has delivered outstanding results and that a malaria one shows early promise.

Until very recently, Ebola barely registered with the public. If people were aware of the disease, it was as a plot device in films where its exceptionally high mortality rate – rising to 90% – made it something to be feared. But previous outbreaks passed almost unnoticed with only a few hundred cases in the worst instances. This all changed last year, as urbanisation and greater mobility combined to produce the worst outbreak of the disease ever. In all, more than 11,000 people died with more than twice that number infected.

Without diminishing the seriousness of Ebola, malaria is simply in another league. Every year, the disease infects an estimated 200 million people, and kills half a million of them. The scale of this menace is hard to comprehend. 

This is why the news of these two vaccines is so exciting. The Ebola vaccine provided complete protection against the disease in a trial involving thousands, and may spell the end of the disease just as it emerges as a serious health threat. And while the malaria vaccine is unlikely to have the same impact – it only protected a third of children from the severest form of the disease – it shouldn’t be dismissed. This is the first vaccine that’s shown promise against any major parasitic disease; the fact that it was able to bring the immune system to bear on a parasite – a notoriously tricky target – is a cause for optimism.

But these vaccines offer more than an end to sickness, they represent a means for entire countries to improve their social and economic conditions. This is one of the principal reasons that charitable foundations are so keen to get involved in efforts to develop vaccines. Disease is a drag on development: nations free from malaria have a GDP per capita five times that of those where it is endemic. On top of this, economic growth is slower in countries where malaria is endemic – these countries are losing ground on the rest of the world every year. The elimination of malaria in the US, Spain and other countries is acknowledged to have stimulated economic growth, something that’s desperately needed in countries afflicted by this disease.

Given the terrible foes that vaccines have slain – smallpox now extinct and polio on the critically endangered list – and those now in their sights, you’d imagine that people would be lining up to sing their praises. But life is not so simple. A growing movement, strongest in the west, is convinced that many vaccines are unnecessary or even pose a serious threat to children’s health. Many of these campaigners have never seen first-hand the deadly consequences of illnesses, such as measles, which have been tamed by vaccination. This pernicious pseudoscience needs to be fought wherever it is found or vaccination could fall from public favour. To paraphrase, eternal vigilance is the price for the world’s health.