What if a first infection with Covid-19 did not protect us against contamination by its variants?
A first case of reinfection by the South African variant of a patient who has already contracted Covid-19 was noted in the Hauts-de-Seine.
As the variants spread, the question arises.
In France, the British strain could have taken over as early as March, while the Brazilian and South African variants are developing in parallel.
What do we know about re-infections?
Can we be contaminated twice by Covid-19?
If they are rare, re-infections do exist.
However, they are only very rarely noted, the symptoms during a second infection being, according to several studies, less or nonexistent.
The first case of reinfection, detected in August in Hong Kong, had also been by chance, the traveler having to produce a test to travel.
In mid-January, South Africa had reported 4000 "potential re-infections".
The situation seems the same in Manaus, cradle of the Brazilian variant.
In a study published at the end of January in The Lancet, a researcher noted that in October, 76% of the population had already been infected with the original strain of Covid-19.
But it is clear that despite this high level of contamination, the number of cases and hospitalizations exploded in December and then in January in Manaus, thanks to the spread of the Brazilian variant.
The World Health Organization (WHO), through the voice of Soumya Swaminathan, its chief scientist, sounded the alarm on Friday: "We are currently receiving reports of people re-infected with a new variant. of the virus, suggesting that people who were previously infected may be infected again.
"Olivier Véran, the Minister of Health, during his press conference Thursday, did not say anything else:" They can
cause
(
Editor's note
: the Brazilian and South African variants
) reinfections in people who have already contracted the Covid-19.
"
What do we know about the Hauts-de-Seine case?
The case currently at the Louis-Mourier hospital in Colombes (Hauts-de-Seine) comes out of this standard pattern.
In September, a patient arrives at the hospital.
He is 58 years old and has "moderate breathing difficulties".
After a few days, he came out in great shape and tested negative twice, as described in the study published Wednesday in the journal Clinical Infectious Diseases.
In January, 129 days after his first infection, this patient was admitted to hospital again, but his condition was more severe and he had to be placed on life support.
The result is clear: it is positive for the South African variant.
"It is a reinfection which leads to a more serious form than during the first infection", describes, to the Parisian, the professor Jean-Damien Ricard, head of the intensive care unit of Louis-Mourier.
"This may be linked to a greater virulence of the South African variant - although this has not been clearly established to date - but it is also possible that the patient has a particular susceptibility to viral infections", specifies Fabrice Uhel, resuscitator, who wrote the study with Noémie Zucman.
The patient is still in intensive care today, in a "serious state".
"We do not have a more serious form than what we have with other Covid patients, however, points out Jean-Damien Ricard.
The support remains the same.
The family agreed to publish this study regarding this case, in order to advance the research.
What about natural immunity?
These cases of reinfection add more questions to all those already posed about natural immunity.
The body, once confronted with a virus, develops antibodies in order to protect itself against a future infection: this is called "natural immunity".
But for now, we do not know what really is with the Covid-19.
"We just know that not everyone has perfect immunity to the virus," explains Jean-Damien Ricard.
First in June, then in November, researchers took samples from caregivers at the Toulouse University Hospital (Haute-Garonne).
In a study published at the end of January, they revealed that among the 3% who had antibodies against Covid-19 during the first sample, less than 2% reported reinfection during the second.
A tiny number that makes researchers say that natural immunity lasts at least six months, joining other studies.
But this is a question ... of the original strain of Covid-19.
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Mutation, variant, strain: the lexicon for understanding the evolutions of the coronavirus
"There are thousands of variants of SARS-CoV-2, because the virus mutates frequently," explains Fabrice Uhel.
Among these, so-called worrying variants which have mutations targeting in particular the
Spike
protein
, which allows the virus to interact with the organism.
These mutations then give the virus certain advantages: it becomes more contagious, more virulent, even capable of bypassing the immune system… ”Can the virus's mutations be so important that they cannot be recognized by the antibodies?
“It's a hypothesis,” explains Jean-Damien Ricard.
The British variant as we know it has, a priori, very little mutated and remains recognized by the antibodies.
The South African and Brazilian variants have undergone larger mutations, in particular with a mutation (called E484K) which seems capable of reducing the recognition of the virus by the body.
"As such, the mutation helps the virus to bypass the immune protection provided by an infection or a previous vaccination", already warned, in early January, François Balloux, of University College London at Science Media Center.
The British variant, since its first discovery, could have inherited this same mutation.
What impact on vaccination?
South Africa has suspended its vaccination campaign, deciding not to use the AstraZeneca vaccine on which there are doubts about its effectiveness on the South African variant.
In a study published Feb. 7, the University of Witwatersrant, Johannesburg, reported that the vaccine offered "limited protection against moderate forms of the disease caused by the South African variant in young adults."
Thought with the original strain of Covid-19, the vaccine would target a virus with an identity card that is no longer so much its own, as the mutations would have transformed it: the antibodies of the vaccinee would therefore not recognize the southern variant. African.
AstraZeneca is already working to offer a second version of its serum.
Most of the other vaccine makers have previously said that their vaccine works against the variants, but may be a little less effective.
During his press conference on Thursday, Olivier Véran indicated that among the new contaminations in France, 4 to 5% were contaminations due to the South African and Brazilian variants.
In Moselle, more than 400 cases of the South African variant have been detected.
Asked about a possible change of gear vis-à-vis the vaccination campaign, the Minister of Health replied "no".
"There is little scientific data at this stage that can be used to judge whether vaccines are really less effective on these variants," he explained.
"The description of this patient's case should encourage further investigations in order to know to what extent vaccines, or a previous infection, confer effective protection against new variants", explains Fabrice Uhel, who recalls the importance of barrier gestures, "including if you have already had a Covid infection".
Jean-Damien Ricard calls for him to "investigate further" to see if his patient is a unique case or not.
And the professor insisted: “There are not yet a lot of patients with cases of reinfection.
"