However, there are still many questions to answer.
The vaccine was given as a nasal spray in the experiments, but may need to be breathed in through a nebuliser to reach the depths of human lungs.
It is not known whether the same effect can be achieved in people or how long the immune system would stay in amber alert. There are differences in the immune systems between mice and humans, including our immunity being shaped by decades of infections.
So the researchers are planning trials where one person is vaccinated and then deliberately infected to see how their body copes.
There may also be consequences to dialling up the immune system beyond its normal state – raising questions of immune disorders.
Jonathan Ball, professor of molecular virology at the Liverpool School of Tropical Medicine, said the work was undeniably “exciting” but cautioned “we have to ensure that keeping the body on ‘high alert’ doesn’t lead to friendly fire, where a hyper-ready immune system accidentally triggers unwelcome side effects”.
The research team in the US does not think the immune system should be permanently dialled up and think such a vaccine should be used to compliment rather than replace current vaccines.
In the first stages of a pandemic, like early 2020 with Covid, a universal vaccine could buy time and save lives while a specialist vaccine was being developed.
“That would reduce mortality, disease severity, and perhaps build up a level of immune resilience that would have a huge impact,” says Pulendran.
The other scenario is at the start of winter when the usual wide range of winter bugs start to spread, “one could imagine a seasonal spray that could be administered to imprint broad immunity” against them all.
Correction 19 February: This story was updated after an earlier version referred to Edward Jenner using the title Sir, when in fact he was never knighted.