Intended for healthcare professionals


Sixty seconds on . . . outbreak

BMJ 2020; 370 doi: (Published 20 July 2020) Cite this as: BMJ 2020;370:m2900

Read our latest coverage of the coronavirus pandemic

  1. Abi Rimmer
  1. The BMJ

The Dustin Hoffman movie?

Sadly not, although the film’s introduction feels relevant: “The single biggest threat to man’s continued dominance on the planet is the virus.” Instead, we are concerned with the use of the word “outbreak.”

Is it bugging people?

I should say so. Peter Soulsby, the mayor of Leicester—which has been under local lockdown for the past few weeks—has questioned its use. He is (perhaps justifiably) confused because, despite being told by Public Health England on 15 June that no covid-19 “outbreak” had been identified in his city, the health secretary, Matt Hancock, announced on 18 June that there was an “outbreak” in Leicester.1

Why does that matter?

In this case, because it just adds to the confusion. At the time, Soulsby said that Leicester had only one covid-19 testing station and that the city council did not receive the data it had requested on the number of people who had tested positive until 11 days after Hancock’s declaration of an “outbreak.”2

But what does “outbreak” mean?

Good question. Public Health England usually defines an outbreak as “two or more people experiencing a similar illness, which appears to be linked to a place.”3 But it can also be “a single case of an unusual or rare infection” or “a greater than expected rate of infection compared with the usual background rate that is expected in that population for that place or time.”4

Confusing . . .

Yes—and it gets worse. The World Health Organization describes a disease outbreak as “the occurrence of disease cases in excess of normal expectancy.”5

Should we stop using it?

Well, maybe not. Jimmy Whitworth, professor of international public health at the London School of Hygiene and Tropical Medicine, says that it is quite valid to use the term when there are more cases of a disease than expected, as was the case in Leicester.

So, “outbreak” isn’t cancelled?

No, it’s still OK. But, as the movie’s strapline says, “Try to remain calm.”

This article is made freely available for use in accordance with BMJ's website terms and conditions for the duration of the covid-19 pandemic or until otherwise determined by BMJ. You may use, download and print the article for any lawful, non-commercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained.