The title bars the front page of many British tabloids.
“Zero Covid death”, they exclaim in chorus this Wednesday, June 2.
For the first time in almost a year, no death linked to SARS-CoV-2 has been recorded in 24 hours in the UK, largely deconfined.
Yet the country is the one in Europe whose situation worries the most.
Because this collapse in daily mortality takes place in parallel with a fairly notable increase in the number of new daily cases of Covid-19, from a little more than 2,000 to almost 4,000 in twenty days.
Over the past week, the increase reached 40%.
The reason ?
Much of the spread of the so-called "Indian" variant B.1.617.2, dubbed Delta by the World Health Organization.
Now dominant across the Channel (more than 50% of new cases sequenced every day), it is more transmissible than the original strains and "it is very likely" that it is also "significantly more" than the variant says " British ”, according to Public Health England (PHE).
An increased risk of hospitalizations?
More worrying, according to new data released by the health agency Thursday evening, this variant would also lead to a risk of hospitalization up to 2.5 times higher.
“This is not good news for those of us who believe in the old adage that viruses evolve to be more transmissible and less virulent,” commented PHE epidemiologist Meaghan Kall.
It's not good news for those of us who believe the old adage that viruses evolve to become more transmissible and less virulent ...
However we have a strength of finding that suggests a more severe outcome for Delta infection, even after adjusting for vaccine status.
- Meaghan Kall (@kallmemeg) June 3, 2021
“These data are preliminary and the level of confidence is considered limited.
But it is a signal that we are following with the greatest vigilance, ”replied this Friday morning during a press point Sibylle Bernard-Stoecklin, from the Infectious Diseases Department of Public Health France.
Read also Indian variant: how its progress is monitored in France
This Delta variant also appears to decrease the effectiveness of vaccines, especially after a single injection.
The good news is that two doses would still be quite effective, several studies suggest.
Only 5% of people who died after being infected with this variant in England were also fully vaccinated.
Looking at the curve of new cases over time in the United Kingdom, some are also tempted to put it into perspective. At the peak reached in mid-January, nearly 60,000 new cases were recorded every day, or 15 times more than today. Yet many scientists are sounding the alarm. "Yes, the cases are low, but the exponential spread is ruthless once the R exceeds 1. The cases are at the same level as in mid-September and they had almost tripled in 4 weeks," insisted on Twitter l epidemiologist Deepti Gurdasani.
But how can we be in a crisis when cases are low?
Yes, cases are low, but exponential spread is unforgiving once R rises above 1 - and it is above 1 now.
The no.
of cases are at a similar level to where they were in mid-September & cases almost tripled in 4 wks.
pic.twitter.com/5jO052kZ79
- Deepti Gurdasani (@ dgurdasani1) May 31, 2021
This reproduction number "R" corresponds to the number of cases that an infected person will contaminate on average.
If it is above 1, the epidemic is progressing.
“The R is currently at 1.16 in the UK and has been above 1.10 for several weeks.
The British authorities are right to be concerned, ”underlines epidemiologist Antoine Flahault, director of the Institute for Global Health in Geneva.
"Beginning of localized community transmission" in France
Several elements can explain the contrast observed with the daily mortality curve.
There is always a latency effect between contaminations and deaths, which usually occur between three and four weeks later.
“When we observed a growing increase in new daily cases in the south of France at the end of last summer, mortality was still very low,” recalls Antoine Flahault.
On the other hand, the elderly, the most at risk of dying from Covid-19, are also the most heavily vaccinated.
Under pressure while the last stage of deconfinement scheduled for June 21 could be postponed, the British government has already reduced the time between the two doses of Pfizer vaccine to eight weeks instead of twelve for those over 50 years old.
Read alsoCovid-19: contagiousness, vaccine effectiveness ... what we really know about the "Indian" variant
In France, where the delay is 6 weeks, 54 episodes of at least one positive case for this variant have been identified.
But "recent data show the start of localized community transmission in certain regions," said SPF in its weekly bulletin published on Thursday evening.
At least four homes, including one in a family in the Landes, have no known link with foreign countries.
