By Debora MacKenzie
Passengers arriving from Italy at Debrecen International Airport, Hungary are being screened for signs of covid-19
Akos Stiller/Bloomberg via Getty Images
Prepare for a pandemic, says the World Health Organization, as the global spread of Covid-19 soars by the hour. Its not a matter of if, but when, say US health officials.
Yet so far the WHO refuses to actually call 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 combating covid-19 and the WHO doesnt want countries to lurch in the wrong direction.
The US Centers for Disease Control and Prevention says the covid-19 virus already meets two of its three criteria for a pandemic: it spreads between people, and it kills.
The third is that it has to spread worldwide. The virus is now in 38 countries – and counting – on nearly all continents, and those are just the ones we know about. How much more worldwide does it need to be?
Epidemic experts say there are no global criteria. There used to be for flu pandemics, but the WHO abandoned them when it was criticised after declaring a flu pandemic in 2009 and triggered expensive countermeasures in some countries, which some deemed unnecessary.
That bruising could be one reason the WHO seems anxious to avoid the P-word now. But there is a more important one.
There are two kinds of response to a growing pandemic. The first is containment: as cases appear, you can isolate each person then trace and quarantine their contacts. That worked for SARS and the 2014-2016 Ebola outbreak.
The second is mitigation. If containment only slows the virus, eventually you get community spread: people are infected without knowing how they were exposed, so you cant quarantine all contacts. All you can do is slow the epidemic so it wont peak massively and quickly, overloading health facilities. You close schools, cancel mass gatherings or as China did, and Italy is now doing, shut down whole cities when they have community spread.
Flu skips between people so quickly that containment is a non-starter. Pandemic plans are mostly designed for flu, including those of the UK and the US, and they go straight to mitigation. The UK plan suggests containment only if a new pandemic flu hasnt learned yet to spread as fast as normal flu.
In this light, statements from WHO start to make sense. Its not either/or, said WHO director Tedros Adhanom Ghebreyesus this week. We must focus on containment while doing everything we can to prepare for a potential pandemic. David Heymann, who led the WHOs fight against SARS, says you need both containment and mitigation.
Bruce Aylward of the WHO, just back from heading an international mission to China, reports that it used full-on mitigation – stopping travel, keeping people inside, shutting down the huge city of Wuhan – in Hubei province, which had community spread before control efforts even began.
Everywhere else, China stopped community spread from developing by contact tracing and quarantine – and reminding everyone to wash their hands and monitor their temperature. Some places also used mitigation measures such as cancelling public gatherings, school and work as well. The key, says Aylward, was tailoring the approach to local circumstances.
That seems to be the WHOs concern: call this a pandemic, and countries will apply blanket measures designed for flu. People think its like SARS so you do things that way, or its a pandemic so you run and mitigate, Aylward said during a press conference in Beijing. If we only approach it with a binary SARS-influenza mentality, we are not going to have the agility of approach that weve seen in China that is going to be fundamental to beating this on a global scale.
Yet thinking seems to be binary. Nancy Messonnier, head of the CDCs centre for respiratory diseases, says the US will use containment until it gets signs of community spread then the strategy will change.
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 WHOs reluctance to call a pandemic, WHO spokesperson Tarik Jasarevic said it is important to focus on actions and not on words.
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 Britain. Risk communication experts warn that not telling the public that containment will not prevent a pandemic but might still slow it – risks greater shock over what comes next.
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By Debora MacKenzie