A document to end the skepticism surrounding anti-Covid-19 vaccines?
Probably not.
The latest study by the Directorate of Research, Studies, Evaluation and Statistics (DREES), published Thursday evening July 15, could however convince some.
During the week of June 28 to July 4, the administration linked to the Ministry of Health looked at the 2120 PCR tests found to be positive per day on average.
The result is clear: the vast majority of these new positive cases concern unvaccinated people.
Read also: Variant Delta: the rebound could be controlled with the increase in vaccination
Thus, 1,700 positive tests per day, or 80%, concern people who have not received any injection.
People who received only one dose less than 14 days ago (recent first dose) represent 3% of cases, those who received it more than 14 days ago or who received their second one earlier. less than seven days (first effective dose) are 11% positive.
As for people who are fully vaccinated, they only represent 6% of contaminations, while at the same time, 32% of the French population has completed their vaccination cycle.
By restricting ourselves to only patients declared symptomatic, the proportion of fully vaccinated persons who test positive drops to 4%.
The vaccine also works for the Delta variant, which affects young people more
These data, which already exist in some foreign countries, were eagerly awaited in France.
They also provide proof that vaccination remains effective against the Delta variant, which has since become the majority in France.
According to the Drees study, this mutation of the virus affected around 380 people per day on average from June 28 to July 4, out of 1,700 positive tests.
During this period, 5.5% of the cases tested with the Delta variant had a complete vaccination schedule.
A proportion which drops to 4.7% for symptomatic cases.
The protective effect of vaccination against infection therefore does not appear to be significantly different for this particular mutation.
Read also: In teens too, the benefit of vaccination outweighs the risks
Another lesson: the Delta variant seems to affect young people more.
Thus, "
the numbers of tests identifying the so-called L452R mutation are more concentrated on populations of young adults than the numbers of positive tests not carrying this mutation
", indicates Drees.
Thus, during the week of June 28 to July 4, almost 180 people aged 20 to 30 tested positive for the Delta variant, 80 for the 10-20 year old group and a little more than 80 for the 30-40 year old group. .
By way of comparison, the 40-50 year olds are only 59 to have been affected by the mutation, and the 50-60 year olds barely 45. But in all cases, the proportion of people benefiting from a complete vaccination schedule remains. minimal.
Data to qualify
However, these figures should be qualified for a simple reason: the fully vaccinated people are tested much less than the first dosed or the non-vaccinated. And this should intensify with the widening of the health pass, which will push them, often without symptoms, to be tested for reasons of comfort. Thus, “
an increase in negative results for unvaccinated patients should lower the positivity rate in this population, via an effect that does not exist for the vaccinated (who are tested, a priori, only for health reasons)
", Underlines the Drees, which concludes:"
All these factors affecting the aggregate results show that it is not possible to estimate precisely the
vaccine efficacy via simple descriptive statistics ”.
Read also: Covid-19: the higher the income, the higher the vaccination rate, according to a study
While traveling to a vaccination center in Chambéry (Savoie), Thursday July 15, the Minister of Health Olivier Véran relied on this study to announce that "
96% of French people who have contracted Covid-19 with symptoms the last week were not vaccinated
”.
He also added that "
when you are vaccinated you are at least four times less likely to catch Covid
".
