The Conversation Vaccines have traditionally worked by teaching the immune system to recognise a specific virus or bacterium – in effect, showing it a wanted poster for a single suspect. But what if one vaccine could protect against dozens of different infections at once? Researchers have now developed a potential candidate for such a vaccine, and a new study in mice, published in the journal Science, has given promising results.
What is this new vaccine, and how does it work?
Most vaccines work by introducing the immune system to a specific pathogen – a weakened version of it, or a key protein from its surface – so that the body can recognise and fight it if encountered later.
This vaccine takes a fundamentally different approach. Rather than targeting any one bug, it contains molecules that mimic the signals the body naturally produces when it is under attack from a virus or bacterium. The effect is to put certain immune cells into a prolonged state of high alert, ready to respond rapidly to a wide range of threats, rather than being trained to spot just one.
However, the consequences to dialling up the immune system beyond its normal state won’t be known until human trials are conducted.
Why is it given as a nasal spray rather than an injection?
The nose, throat and lungs are lined with what scientists call mucosal surfaces – the moist tissues that act as the body’s main point of contact with the outside world, and its first barrier against infection. The immune system in these tissues responds more powerfully when a vaccine is delivered directly to them, rather than into a muscle in the arm.