Overview of Covid-19 cases rising in much of the world--the Economist, with graphs

Covid-19 cases are rising again in much of the world More transmissible variants, rather than changes in behaviour, are largely to blame The Economist

LIKE A STORY-BOOK villain, the covid-19 pandemic has a habit of fighting back from the brink of defeat. Last summer politicians were quick to assume that the coronavirus had been squashed, only for a second wave to engulf much of Europe and North America in the autumn.

Then, as vaccine programmes got under way in December, new mutations of SARS-CoV-2 emerged that may lower the efficacy of those vaccines.

Today a third wave of infections is sweeping through Europe, forcing many governments to impose another round of lockdowns. From midnight on March 19th, 21m people in France will enter a new month-long lockdown, on top of a nationwide curfew that has been in place since January 16th. Angela Merkel, Germany’s chancellor, warned that her country would probably need to apply an “emergency brake” and reimpose a lockdown.

The recent rise in global cases is worrying. They fell by half between January 11th and February 20th, but have since risen by 30% from that low point. Cases are currently highest in Europe, particularly in eastern Europe. Both Estonia and the Czech Republic are recording more than 100 new cases per 100,000 people a day.

In the EU as a whole, that rate is 31 per 100,000, not far below the mid-January peak. Hospitals beds in the worst-affected places are full. Cases are also surging in Latin America, where they are up by a third since February.

There are at least two possible explanations for this latest wave. First, as vaccines were rolled out and case numbers fell in many places, people may have let down their guard. Longer days in the northern hemisphere may also be encouraging people to socialise. Yet in the EU and Latin America, mobility data from Google shows that footfall in shops and on public transport—just the kind of places where SARS-CoV-2 is most likely to spread—remains at the average level for the period since October 2020.

The second cause may be the spread of new, more contagious, variants. The one first found in Kent, England, known as B.1.1.7, is thought to be around 30% more transmissible and may be deadlier. Since its genome was sequenced on September 20th it has accounted for 55% of all cases in Britain.

Border controls in Europe have failed to stop its spread. It was detected in the Czech Republic in January and has accounted for 80% of cases sequenced in the country since then. In France, 60% of the sequenced cases since February have been this variant. Perhaps more worrying is B.1.351—first found in South Africa—which has been shown to be better able to avoid antibodies generated by vaccines. Since February it has accounted for 5% of cases sequenced in France and 8% in Belgium.

Countries that have succeeded in rolling out vaccines quickly have, for now, avoided surges in new cases. ...