Abstract
There are no criteria for a pandemic, but covid-19 looks like one, says Debora MacKenzie
PREPARE for a pandemic, said the World Health Organization, as the global spread of covid-19 began to soar. Yet so far the WHO isn't calling covid-19 a pandemic. Why?
The answer may lie with what kicks into gear when we deploy the p-word. Countries have pandemic plans that are launched when one is declared, but these plans may not be appropriate for covid-19.
There are no global criteria for a pandemic. There used to be for flu, but the WHO abandoned them when it was criticised after declaring a flu pandemic in 2009 that triggered expensive countermeasures in some countries.
That could be one reason the WHO seems anxious to avoid the word pandemic for now. But there is a more important one.
There are two responses to a growing pandemic. The first is containment: as cases appear, you isolate each person then trace and quarantine their contacts. The second is mitigation, such as cancelling mass gatherings. If containment only slows the virus, eventually you get “community spread”: people are infected without knowing how they were exposed, so you can't quarantine all contacts. All you can do is try to slow the epidemic so it won't overload health facilities.
Normal flu skips between people so quickly that containment is a non-starter. Pandemic plans are mostly designed for flu, and they go straight to mitigation. The UK plan suggests containment only if a new pandemic flu isn't yet able to spread as fast as normal.
In this light, statements from the WHO start to make sense. “It's not either/or,” said WHO director Tedros Adhanom Ghebreyesus last week. “We must focus on containment while doing everything we can to prepare for a potential pandemic.”
Meanwhile, the WHO seems to have a third problem with the p-word. “Using the word pandemic now does not fit the facts but it may certainly cause fear,” said Tedros. Asked about the WHO's reluctance to declare a pandemic, a spokesperson said: “It is important to focus on actions and not on words.”
True – but words matter. Reluctance to tell the public the truth for fear of causing panic has plagued responses to other disease emergencies, notably BSE in the UK.