Some Vaccines Are Doubly Beneficial, Have Provided Hidden Protection From Diseases for 100 Yrs
Last edited Thu Dec 17, 2020, 03:41 PM - Edit history (1)
'The mystery of why some vaccines are doubly beneficial.' BBC News, Sept. 16, 2020. Vaccines have been providing a kind of hidden, unintended protection for over a century. Now scientists are racing to find out how it works.
Peter Aaby shakes his head, as though he still can’t believe it. “That was the start of it really – something very strange happened,” he says. Today Aaby is speaking with me via Skype from his native Denmark. But he has spent the best part of the last four decades in Guinea-Bissau – a small, impoverished West African country with a troubled colonial past and recent history of repeated coups d'état. He moved there in 1978 to set up a charity, the Bandim Health Project.
At the time, there was no national programme of measles vaccinations, so after a particularly devastating outbreak, the team decided to focus their efforts on providing them for children in the local area. It was around a year after the vaccinations began that they made an extraordinary discovery: those who had been vaccinated against measles were 50% less likely to die than those who hadn’t. “It was stunning,” says Aaby – but not for the reasons you might at first think. The thing is, measles was never killing anywhere near half of Guinea Bissau’s children.
Based on the proportion who were dying of the disease originally, the vaccine should have been far less beneficial than it was. The numbers didn’t add up. “We were asking ourselves ‘How can this happen?’,” says Aaby. In the large-scale trials that followed, it emerged that the vaccination was reducing the chances of children dying by a third (other studies led to significantly higher estimates) – while only 4% of this decline was explained by the fact that it was preventing them from catching measles. This is the power of a mysterious phenomenon Aaby has called “non-specific effects”.
Happy accidents: For more than a century, certain vaccines have been providing us with a kind of clandestine bonus protection – one that goes far beyond what was ever intended. Not only can these mysterious effects protect us in childhood, they can also reduce our risk of dying at every stage of our lives. Research in Guinea-Bissau found that people with scars from the smallpox vaccine were up to 80% more likely to still be alive around three years after the study began, while in Denmark, scientists discovered that those who had the tuberculosis vaccine in childhood were 42% less likely to die of natural causes until they were 45 years old...
More, https://www.bbc.com/future/article/20200915-the-mystery-of-why-some-vaccines-are-doubly-beneficial