The Delta variant is still developing in France. This mutation of the virus responsible for Covid-19 now represents “about 20% of new diagnoses” and “gradually becomes dominant” in France, Health Minister Olivier Véran announced on Tuesday, June 29, on franceinfo. According to him, this variant “more contagious” like the others, don’t refuse parade: vaccinations. “All research shows that if you get vaccinated and then get infected, you don’t get a serious form”, he assured.
At this stage, there is no evidence to support this confirmation for the Moderna and Janssen vaccines. The available studies on the vaccine’s efficacy against the Delta variant relate only to the doses produced by Pfizer and AstraZeneca, which represent 89% of the first injections in France. Here’s what to remember.
Pfizer BioNTech Vaccines
• Very high efficiency against severe mold. After two doses, the Comirnaty vaccine developed by the Pfizer-BioNTech alliance was 96% effective against the risk of hospitalization associated with the Delta variant, according to previously published studies (in English) held from 12 April to 4 June by UK health authorities, posted on 14 June. After a single dose, the efficacy rate is estimated at 94% according to the authors of this critical study. This is a more encouraging result compared to the Alpha variant, which has been identified in the UK (83% efficacy after one dose and 95% after two doses).
• Strong but less efficiency compared to lighter forms. In May, in other “pre-print” studies (in English), the same research team reported protection data this time against the general form of symptoms. The results of the American-German vaccine are a little less convincing: Komirnati presented as 33% effective against variant B.1,617.2 after one dose (at 51% against variant Alpha) and at 88% after two doses (at 93% against variant Alpha). According to a study by the Scottish Health Authority, it is not peer-reviewed and published in Lancet (in English) starting June 26, efficacy was estimated at 79% against the Delta variant at least two weeks after the second dose (at 92% against the “UK” variant).
• Less antibodies are present compared to other variants. End of May the work of the Pasteur Institute (in English) suggested good antibody efficacy after two doses, even if it was less than against other variants. In a correspondence published in early June at Lancet (in English), British investigators reported that levels of neutralizing antibody were nearly six times lower in the presence of the Delta variant than in the presence of the historical strain of the virus, which is used to design vaccines. In comparison, this level is 2.6 times lower than the Alpha variant (identified in the UK) and 4.9 times lower than the Beta variant, identified in South Africa.
Vaccination against AstraZeneca
• High efficacy against severe forms, especially after two doses. After completing a two-injection cycle, the Anglo-Swedish vaccine provided an estimated 92% efficacy against the risk of hospitalization associated with the Delta variant, according to mestudy (in English) pre-published on 14 June by UK health authorities. According to people who received only the first dose, continued protection was 71%. In comparison, the reported efficiency versus the Alpha variant, identified in the UK, was 76% after one dose and 86% after two doses.
• Efficacy is limited in terms of symptoms. In cases where there was no need to go to the hospital, the efficacy of Vaxzevria against the Delta variant was 33% after one dose (at 51% against the Alpha variant) and 60% after two doses (at 66% against the Alpha variant). other pre-publications (in English) unveiled by Public Health England on 24 May. YOUborn Scottish Health Authority Study, published in Lancet (in English) June 26, 60% effectiveness was also estimated at least two weeks after the second dose. However, youonly one dose of this vaccine appears “little or ineffective” against the Delta variant, underscores Olivier Schwartz, co-author of a intermediate studies by the Pasteur . Institute (in English) on the immune response after the first dose.
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