“Without an adjuvant, antibodies will generally disappear, maybe after a few weeks or months. But with adjuvants they might last for a few years.” says Bingbing Sun, a chemical engineer at Dalian University of Technology, in the Chinese city of Dalian. He gives the example of certain types of hepatitis B vaccine. “If they don't include adjuvants, antibody production will be very, super low. They don't really have the ability to induce antibody production,” he says.
For over a century, why these apparently random ingredients are so essential to vaccines has remained a total mystery. Now scientists are racing to unravel their secrets.
A mistaken scandal
First up, though the concept of additives in vaccines might sound alarming, they’re included in microscopic quantities. There is as little as 0.2mg of aluminium in a typical vaccine dose, which is equivalent to less than the weight of a single poppy seed. The weight of evidence is that adjuvants do not lead to serious side-effects.
In fact, safety is the reason adjuvants were popularised in the first place.