California is in the grip of a whooping cough epidemic, with 800 cases reported in the first two weeks of June alone. Outbreaks like these are not uncommon in the US.

It’s nothing short of “insane,” fumes political blogger Ezra Klein, founder of news site Vox: “These sentences should only exist in musty newspapers from decades long past. They shouldn’t need to be written in 2014. Whooping cough is a solved problem in medicine.”

Medicine may have “solved” the problem, but—as a prospective cohort study just posted on bmj.com confirms—the question of how best to vaccinate communities remains.

It’s not just about adherence (although Julie Jacob’s Feature on “vaccine hesitant” parents is worth a read). Researchers from the University of Oxford and Public Health England found that a fifth of children who presented to their GP with a persistent cough had whooping cough, even though most had been fully vaccinated.

The pertussis vaccination does not give lifelong immunity, which is why the UK, in common with other countries, introduced a pre-school booster in 2001, on top of the initial schedule at 2, 3, and 4 months. But those that had gone more than seven years without the vaccination were three times more likely to develop the infectious disease, the study found.

In the US, whooping cough was reported to cause absence from school in 83% of adolescents over a two year period. Given the findings of this new bmj.com study, how long before the UK introduces an adolescent booster to better protect young people?

Rebecca Coombes is the features editor, The BMJ.