Bonus Protections from Vaccines

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.

Evidence from trials in the impoverished African country of Guinea-Bissau showed vaccines often conferred protection against other diseases

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. It’s also true in dogs: an experiment in South Africa found that dogs that had been vaccinated against rabies had much higher survival rates, beyond what would be expected from their immunity to rabies alone.

Other happy accidents include protecting us from pathogens which are entirely unrelated to their target, reducing the severity of allergies, fighting certain cancers, and helping to prevent Alzheimer’s disease. The tuberculosis vaccine is currently being trialled for its ability to guard against Covid-19, though the microorganisms behind the two diseases are entirely different – one is caused by a bacterium, the other by a virus. And the two are separated by 3.4 billion years of evolution.     

Despite decades of research, these surreptitious effects still haven’t given up their secrets. But until we understand them, scientists are reluctant to use them to their advantage – so the race is on to find out what’s going on.

The benefits of the BCG

Though the existence of “non-specific effects” wasn’t well-established until Aaby’s work in the 1980s, scientists have suspected for far longer that something weird happens when we’re vaccinated.