Coronavirus: more than 12,000 cases in Switzerland

By mid afternoon on 27 March 2020, Switzerland had 12,331 recorded cases of Covid-19.

Only seven other countries had more cases. USA (85k), China (81k), Italy (81k), Spain (64k), Germany (47k), Iran (32k) and France (29k) all had more recorded cases than Switzerland.

Switzerland, with 13.9 cases per 10,000, led the world in per capita terms. Italy (13.3), Spain (12.4), Germany (5.2), France (4.5) and the USA (2.5) all trailed Switzerland on this measure.

However, many are now questioning the meaningfulness and comparability of these case figures. Different approaches to testing and the challenges associated with picking up mild and asymptomatic cases have raised many questions around the accuracy of these case figures.

Relatively high outcome-based fatality rates in much of Europe are one sign that case numbers might be wildly inaccurate in some places.

So far in China, 74,588 patients have recovered and 3,292 have died, an outcome-based fatality rate of 4.2% (3,292 / (3,292 + 74,588)). On the other hand, so far in Italy, 10,361 have recovered and 8,215 have died, an outcome-based fatality rate so far of 44.0% (8,215 / (8,215 + 10,361)).

In an interview with Time, Dr. Bruce Aylward, an infectious disease expert at WHO, says Italy’s high death rate could be explained by age. He said “If you look at Italy, and the age distribution, it’s the second-oldest country in the world after Japan, people forget that. You have an older population number one, they get the more severe disease and they’re more likely to die.”

However, others think it could also be because a large number of mild cases have not made it into the case numbers. Modelling done by Sunetra Gupta, an infectious disease expert at Oxford University, suggests half of the UK population might have already caught the virus.

The theory is that with better testing, Switzerland, instead of having 12k cases might have 55k (this is a wild guess) and that (nearly) all of the extra 43k uncounted cases would be healthy ones that would have flowed through into the number of recoveries. So instead of there being 897 recoveries and 207 deaths and an outcome-based fatality rate of 19% (207/(207+897), there would be 4,707 recoveries and 207 deaths and an outcome-based fatality rate of 4.2% (207/(207+4,707)), the same as China’s.

It is also possible that China’s cases were undercounted. Epidemiological modelling that accounted for “silent” cases estimated a fatality rate of 1.4% in Wuhan. This implies actual cases in Wuhan might have been 3.5 times higher than the official figure. If we apply this 1.4% fatality rate to Switzerland then the implied number of cases in Switzerland would currently be 170,000, close to 2% of the population. It is important to note that these calculations are highly sensitive to the early outcome-based fatality rate which has fluctuated between 19% and 83% since 5 March 2020 in Switzerland – refer to the last chart on this page.

More on this:
Underlying numbers from Worldometers.info (in English)

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