Children whose genetic make-up means they may not be protected by the standard form of a vaccine could in future be given a personalized shot. This is the prospect raised by the discovery of gene variants that seem to predict whether an individual will produce enough antibodies in response to a vaccine to protect them against disease.
Vaccines expose the immune system to a deactivated version of a disease agent. This prompts the production of specific antibodies, which will bind to the real disease-causing agent if the vaccinated person is later exposed to it. Though all of us usually get the same vaccines in the same doses, not everyone produces enough disease-specific antibodies in response. As a result, between 5 and 20 per cent of people vaccinated against hepatitis B, and between 2 and 10 per cent of those vaccinated against measles, will not be protected if they ever encounter these viruses.