When you think of a herd, you probably think of cows, wildebeest or buffalo. In the animal world, there is safety in numbers – more pairs of eyes to look out for predators, for example.

As humans, we don't generally have to worry about predators, but we can gain the protection of the herd in other ways.

"Herd immunity" is the idea that, as long as enough people in a population are immune to a disease (usually through vaccination), they can indirectly protect people who aren't immune from getting infected.

Dr Adam Kucharski is an Assistant Professor of Epidemiology at the London School of Hygiene and Tropical Medicine, where he works on mathematical models of the spread and control of disease.

Microbiology Today is the Society's quarterly magazine. The content is balanced to meet the needs of the Society’s members. The magazine aims to provide informative and enjoyable broad-interest articles for all readers, including parliamentarians and policy-makers. Each issue focuses on a topic, and topics are chosen with the aim of covering all fields of microbiology.

Read more about Herd Immunity in the February 2017 issue of Microbiology Today: http://microbiologysociety.org/microb...

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