The current surge in Covid cases being seen in France and across Europe is sometimes referred to as a fourth wave of the virus, sometimes as a fifth.
The European Medicines Agency and the German authorities attribute the current situation to a “fourth [Covid] wave”, while France’s Conseil scientifique makes reference to a “fifth wave which has clearly been accelerating over recent days.”
In France, the evolution of the Covid pandemic has indeed followed four distinct peaks and subsequent troughs up to this point.
The first wave began to pick up pace in March 2020, prompting the first lockdown, the second following in November 2020, leading to the second lockdown.
This year, a third wave occurred during the spring, and a fourth in summer, curbed by the progress of the vaccination campaign and the introduction of health pass restrictions.
Between the first waves, the number of daily cases fell to around 10,000, while between subsequent surges it dropped to approximately 5,000.
Now, as daily case numbers top 30,000 and the infection rate increases from around 60 per 100,000 people at the beginning of November to 193 yesterday (November 25), another wave of infections is quickly picking up speed.
Elsewhere in Europe, case rate fluctuation has followed a similar trajectory, but has not evolved in the exact same way as in France.
Infection numbers increased across Europe last winter, and again in April and the summer, but not all countries saw the decline in cases that France experienced before the return to school in September.
In Germany, for example, infections stabilised in August after rising in mid-summer, and then started increasing again in October without ever coming down. The same happened in countries including Belgium, Sweden and Greece.
Therefore, for much of Europe, this new escalation is only the continuation of a fourth wave that began months ago.
Epidemiologist Philippe Amouyel, professor in public health at Lille’s Centre Hospitalier Universitaire told LCI at the beginning of this latest surge in cases that a wave is not simply a question of a rise in infections followed by a fall.
“Each time there is a good reason for it,” he said. “Before the first wave, there weren’t any barrier gestures in place. The second was because we had completely relaxed [restrictions] in summer 2020. The third came with the English [Alpha] variant, which was more transmissible. And the fourth was because of the Delta variant, which is even more contagious.”
This time, there are no new variants emerging and certain social distancing and hygiene methods are still in place.
So, “what we are currently seeing are still elements of the fourth wave,” Prof Amouyel said. “The [real] fifth wave will arrive if we encounter a new variant. But at the moment we are still fighting against the same one.”
Therefore, France’s Covid trajectory can be seen in both ways. If you think about the number of times the country has seen cases flow and then ebb, there have been five waves, but if you consider the evolution of the virus itself, there have only been four.