A note of hope, after a start to the year marked by record figures.
For several weeks, the United States, the country hardest hit in the world by the Covid-19 epidemic, seems to have recorded a clear drop in new contaminations and deaths.
"We have seen a continuous decline in Covid-19 cases for the past five weeks, with infections dropping 69% since a peak reached on January 11," commented Dr Rochelle Walensky, director of the Center for Disease Control and Prevention American (CDC) last Friday, during a press briefing at the White House.
Infographic United States Decline in Cases and Deaths
Currently, the average of new cases is below the 70,000 mark, after peaking at nearly 250,000 cases in early January.
The fall is also clear in terms of deaths, in less spectacular proportions: after a peak in January to more than 3,300 daily deaths on average, they have just fallen below the threshold of 2,000 daily deaths on average.
A general trend which is therefore downward, despite some flaws in the monitoring of data (in Texas, some screening centers had to close their doors due to a historic cold snap).
Natural immunity and respect for the rules
The vaccination campaign, which has already allowed 61 million Americans to receive a first injection, would it have borne fruit?
It is still too early to tell, according to several experts, who cite several other explanations for these favorable figures.
Published Sunday, an article by Paul Sax, an infectious disease specialist at Brigham and Women's University Hospital at Harvard, links the phenomenon to a "mixture of several things", in varying proportions depending on the region.
The seasonality of the virus, as well as possible natural immunity, are mentioned in particular, while the epidemic has claimed the lives of nearly 500,000 people.
“Nearly 28 million Americans have had a confirmed diagnosis with Covid-19.
This is only a fraction of the true cases […] and the CDC estimates that only 1 in 4.6 infections are recorded.
Which could lead us to half of the American population, with a certain degree of natural immunity, ”analyzes the clinician.
The nature of certain variants of the virus (not the English variant, he specifies) could also favor less severe forms of the disease - and therefore fewer deaths, or less contamination detected.
“Take the perspective of a virus.
More mild cases are more likely to spread its genetic material to other potential hosts, ”says Paul Sax.
“That's what matters with viruses, isn't it?
"
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Add to these assumptions the change in behavior of Americans after the holiday gatherings that caused the January peak.
"People least likely to follow health rules - or who can the least, because of their job or where they live - have already had Covid-19 and are therefore immune.
The rest have seen cases increase in December and January and continue to confine themselves to the shelter - or have the luxury of being able to stay in the shelter, ”he says.
Watch out for looseness and variants
Seeing the curves decrease, several American states, including Rhode Island, Massachusetts, and New Jersey, have recently decided to increase the maximum reception capacity in places open to the public, such as restaurants.
In New York State, once considered one of the epicenters of the epidemic, restaurants will also be able to welcome a few more customers from next Friday, and retirement home visits will soon resume.
Infographic United States_USA_Covid_cas_deces
The situation remains fragile, however.
“If we follow the sanitary rules, wearing a mask, maintaining a distance, washing hands, we can continue to prevent the spread of the virus.
The challenge is human behavior and adherence to the rules, while there is a real feeling of exhaustion from the Covid, ”said epidemiology professor Sarita Shah, from Emory University.
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"Seeing these numbers drop, particularly in the United States, can give a false sense of security, make people believe that we are out of the woods, when we still have many obstacles in front of us, such as variants and trips. coming for the
spring break
(traditionally festive
spring break
among students, editor's note), ”adds the specialist.
While welcoming the improvement in the health plan, the director of the CDC, Rochelle Walensky, was also allowed to give a brief but clear advice to the Americans: "Stay on your guard".