Abstract
Daily covid-19 cases are rising across Europe, but is that just because countries are performing more tests? Michael Le Page investigates
IN EUROPE, the long-predicted second wave of the coronavirus pandemic is now well under way.
“In some member states, the situation is now even worse than in the peak during March,” said Stella Kyriakides, the European Union's commissioner for health and food safety, on 24 September. “This is a real cause for concern.”
Spain, the Czech Republic, France, the Netherlands and the UK are reporting higher numbers of daily confirmed cases per million people than they did in March, with around 240 per million in Spain. Portugal has the next highest infection rate, but hasn't yet exceeded earlier peak levels.
However, during the first wave, testing was mostly limited to those in hospitals, meaning many cases were missed. Antibody surveys, which estimate the proportion of people who have had the SARS-CoV-2 virus, show that the actual number of cases at the time was much higher than official figures suggest.
“There is undoubtedly more testing being done now than in February and March,” says Martin Hibberd at the London School of Hygiene & Tropical Medicine. “The numbers are difficult to compare.”
The figures should serve as a wake-up call, said Hans Kluge, the World Health Organization's regional director for Europe, on 17 September. “Although these numbers reflect more comprehensive testing, it also shows alarming rates of transmission across the region.”
“Obviously, if you don't search, you don't find,” says Giulia Giordano at the University of Trento in Italy. “However, this does not necessarily mean that now we are discovering more infection cases because we are testing more. The cases may really be more.”
One indicator of how many cases are being missed is the proportion of positive tests, she says. This is rising in most European countries, but isn't yet as high as it was in March.
In Spain, for instance, a third of tests were positive in March. By June, this had fallen to one in 100, but it has now risen to one in 10. In the UK, it is up to two in 100.
If actual case numbers aren't yet as high as they were in March, this would help explain why the numbers of hospitalisations and deaths have remained low even as case numbers have soared. Spain is reporting around two deaths per day per million people, compared with 18 per day per million during the peak of the first wave.
Another reason could be that younger people returning to work and education are the ones being infected while older, more vulnerable people continue to shield. “We do not yet know how impactful the current set of measures will be in reducing SARS-CoV-2 transmission to vulnerable groups,” says Hibberd. “However, with case numbers still rapidly rising, it seems unlikely that they will be sufficient to prevent later increases in hospitalisations and deaths.”
There is undoubtedly more testing being done now than in February and March
Death rates also lag several weeks behind infections. Yet the number of deaths among those infected – the infection fatality rate – is expected to be lower during the second wave. “This would mean we won't see the same impact even if cases did soar,” says Jason Oke at the University of Oxford.
There are many reasons for this. Medical staff have more experience with the disease, for instance, and treatments such as dexamethasone have been shown to reduce the death rate.
The rising case numbers indicate either that people aren't following the measures meant to prevent the spread of the coronavirus or that those measures are insufficient, the European Centre for Disease Prevention and Control said in its latest summary.
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