The Delta variant of coronavirus is a serious concern, as laboratory tests have shown that it is more contagious and resistant than other forms of COVID-19.
However, there are available owners who maintain significant efficacy after two doses.
Here’s what you need to know:
A study published in the journal The Lancet in early June examined the levels of neutralization of antibodies produced in vaccines that were exposed to Delta, Alpha (first identified in the UK) and Beta (first identified in South Africa) variants.
He found that the level of antibodies in people with two doses of the Pfizer-BioNTech shot was six times lower compared to the Delta variant than the original COVID-19 strain on which the vaccine was based.
The Alpha and Beta variants also resulted in lower responses, 2.6 times less antibody in the case of Alpha and 4.9 times less in the Beta.
A French study by the Pasteur Institute concluded that neutralizing antibodies generated by vaccination with Pfizer-BioNTech java is three to six times less effective against the Delta variant than against the Alpha variant.
So do vaccines still work?
Although a key marker, the levels of antibodies measured in the laboratory are not sufficient to determine the efficacy of the vaccine. In particular, they do not take into account the second immune response as killer T cells, which attack already infected cells and not the virus itself.
As a result, actual observations are key to measuring the effectiveness of the vaccine – and the first results are reassuring.
According to data released by Public Health England on Monday, the vaccine with Pfizer-BioNTech and AstraZeneca jabs is as effective as preventing hospitalization in the case of the Delta variant in the case of the Alpha variant.
Two doses of Pfizer-BioNTech proprietary drug prevent 96% of hospitalizations due to the Delta variant, and the AstraZeneca vaccine prevents 92 percent, according to a study of 14,000 people.
Previous data released by British health authorities in late May have drawn similar conclusions in the case of less severe forms of the disease.
The Pfizer-BioNTech vaccine is 88 percent effective against symptomatic COVID-19 caused by the Delta variant, two weeks after the second dose, the jab is 93 percent in cases caused by the Alpha variant.
AstraZeneca shows an efficiency of 60 percent against cases caused by the Delta 60 variant and 66% in the case of Alpha.
Scottish authorities published similar data on Monday in The Lancet.
Meanwhile, the group behind the Sputnik V owner tweeted on Tuesday that its vaccine was “more effective against the Delta variant … than any other vaccine that has published the results of that strain so far.” They have not published the results, but said they have submitted it for publication in a revised international journal of the Gamaleya Center, a Russian research institute.
Is one shot enough?
Among the vaccines available, Johnson & Johnson offers only one dose, more than two, to be effective. For now, there is not enough data to determine how the Delta variant works.
As for other blows, laboratory and real-world tests have concluded that a single dose of any vaccine provides limited protection against the Delta variant.
“After a single dose of Pfizer-BioNTech, 79 percent of people had a quantifiable antibody neutralizer against the original strain, but this dropped to 32% in B.1.617.2. [Delta]”, Said the laboratory research from June.
The Pasteur Institute found that a single dose of AstraZeneca would have “little or no efficacy” against the Delta variant.
UK government data confirms the trend in real-world scenarios: the two vaccines were 33 per cent effective against symptomatic cases caused by the first dose of Delta and three weeks earlier, compared to about 50 per cent efficacy against the Alpha variant.
In the UK – which is currently responsible for 96 per cent of new Delta variant cases – these findings prompted the government on Monday to reduce the dose-waiting period for those over 40 to 12 weeks to eight weeks.
In France, the wait has been reduced to five weeks for the second dose of Pfizer-BioNTech and Moderna vaccines.
Pfizer-BioNTech owners, however, offer very high protection (94 percent) against hospitalization after a dose due to the Delta variant.
So what is the best strategy against Delta tension?
Scientists agree that the best defense against the Delta variant is to get a two-dose vaccine.
Jean-François Delfraissy, a leading French scientist, said that creating a “block of embedded people” would help prevent the Delta variant from spreading to the entire population.
A U.S. study conducted on June 10 indicated the importance of the vaccine to prevent the list of variants from growing.
“Increasing the proportion of the population vaccinated with safe and effective permitted vaccines remains a key strategy to minimize the emergence of new variants and end the COVID-19 pandemic,” he says.
Antoine Flahault, head of the Institute of Global Health at the University of Geneva, stressed that it is still essential to observe social distance, share information on infections and respect restrictions when it is necessary to “keep the circulation of the virus low”.
The more virus circulates, he says, the more chances it has of creating new mutations and variations.