How vaccines really work

Editorial Team

Editorial Team

June 21st, 2013

Editorial Team

‘“People need to understand why vaccines are important not just when a disease is common but also when it has become rare,” according to Professor Adam Finn of the University of Bristol.’

How-vaccines-really-work*Warning* There’s a video of a child who had whooping cough around the 1-minute mark which some may find distressing

In a fascinating TEDmed talk on the value of herd immunity, Prof Finn says the history of whooping cough outbreaks shows the danger of complacency.

In this 7-minute video, Prof Finn begins with a stark reminder of how vaccines have changed our relationship with infectious diseases. “If it weren’t for vaccines half of you wouldn’t be here today – you’d be dead.” Yet this is a message quickly forgotten once epidemics subside.

Background: What is herd immunity?

He looks at data from the 1930s when it was not uncommon for whooping cough (pertussis) outbreaks to kill children. Then, in the 1950s, parents enthusiastically embraced the first pertussis vaccine. The number of cases and the death rate from whooping cough plummeted and the problem appeared to be solved.

Fast-forward to 1978. Everyone had forgotten about whooping cough and complacency was setting in. A theory, later shown to be false, circulated which raised concerns about the safety of the whooping cough vaccine. Confidence plummeted, in some countries –like the UK, Italy and Germany – more than half of all parents stopped using the vaccine, “inevitably the epidemics started again and many young lives were lost”.

Prof Finn brings the presentation to the present by discussing a recent whooping cough outbreak in the UK which prompted the nationwide rollout of a pertussis immunisation campaign for pregnant women. Similar pertussis outbreaks – and vaccination campaigns – have been seen elsewhere in Europe and beyond.

Because women can pass this immunity to their babies before they are born, protecting them for the period where they are considered too young for vaccination, whooping cough rates in infants are now falling again.

The challenge now is to break the cycle of complacency so that the next crisis can be prevented instead of managed.

“People think vaccines work simply by protecting children from [the consequences of] infection. But that’s only part of the story. Vaccination also stops [a child or an adult] from transmitting infection to others, and that’s critical,” says Prof Finn.

“What we need to do now is to explain to one another how we can help ourselves and each other by using vaccines. This is the biggest challenge for immunisation in the 21st century.”

Read our interview with Prof Finn:

How are new vaccines developed?


Pertussis: A Parent’s Story