Although the UK lifted its latest health restrictions, which had raised fears of an explosion in the rate of infections, the opposite has happened as the number of infections has fallen sharply. This phenomenon, which has been observed in other countries, has left scientists baffled.
“It’s inevitable that we’re heading towards 100 000 cases a day,” said Neil Ferguson, a renowned epidemiologist to the BBC on 18 July. Health Secretary Sajid Javid also announced that the latest lifting of health restrictions (Freedom Day) will lead to an increase in the number of infections. At the time, an endemic outbreak had broken out in the country, with the number of daily cases rising fivefold in a month. However, twelve days after a peak of 54 183 infections on 17 July, the number of positive cases dropped sharply to 27 734 on 28 July. This drop was as steep as the surge of this fourth wave, amid a relaxation of sanitary measures and, in particular, the end of the mandatory wearing of masks indoors.
— BBC Politics (@BBCPolitics) July 18, 2021
Many but not very convincing factors
This mysterious decline has baffled researchers. The improvement in prevalence has been explained by a number of factors, such as large numbers of people choosing to isolate themselves because they had been identified as contact cases, or the start of the summer holidays (which began in England last week). The weather, which has also been cited, may also have “encouraged outdoor activity”, which would have limited the spread of the virus, explains Stephen Griffin, associate professor at the University of Leeds Medical School. Another theory is that the European football championships in June and July led to a short-lived Covid wave in the UK as crowds swarmed stadiums and pubs. But the most important of these factors is, of course, the boosting of immunity, either by vaccine or infection. According to the Office for National Statistics, 92% of UK adults are now likely to have Covid-19 antibodies, either because they have had the virus in the past or because they have been vaccinated against it.
A decline has been observed in several other countries.
However, the researchers admit that all this hardly justifies the sharp decline. All the more so as England is anything but an isolated case in Europe. While infection rates in Germany, Italy, and Belgium are still on the rise, several other countries appear to have passed the peak of the epidemic. In the Netherlands, for example, the number of new cases fell from 11,297 positive cases on 16 July to 3,455 on 28 July. Again, there is no convincing explanation for this, especially as this country had pursued the opposite strategy to the UK, implementing stricter health measures such as closing nightclubs. Portugal, France, and Spain also appear to be on a downward trend.
So this fourth wave, which nobody expected (most specialists had predicted a new wave in September with the start of the school year and the arrival of fall), remains as mysterious as the previous ones. In April, for example, the number of infections began to fall just days after the tightening of movement of people, which suggests that the restrictions placed were not the cause of the fall (as it usually takes several days or weeks for the effects to take hold).
The number of deaths is remarkably low despite the high number of cases
It is certain that vaccination had an impact on the number of hospital admissions and deaths. In the UK, 761 people were admitted to hospitals on 26 July, compared with 3812 in January when the Alpha variant arrived. There were also 91 deaths on 28 July, ten times fewer than on 20 January. The same is true in Spain and France, where the number of deaths is remarkably low despite the high number of cases. This difference is entirely due to vaccination, with 70% of UK adults having received two doses of vaccine and 88% having received one dose.
“We’re not out of the woods yet,” Boris Johnson’s spokesman warned on Monday. But this surprising improvement without a new lockdown proves that the worst is never certain.