AstraZeneca Vax Flops against South Africa variant in initial test

AstraZeneca’s COVID-19 vaccine was not protective against the mild to moderate disease of the so-called South African variant (B.1.351) or the wild type virus, a provisional analysis of phase Ib / II data found.

The overall effectiveness of the mild to moderate COVID-19 vaccine in South Africa was 21.9% (95% CI -49.9 to 59.8) and the effectiveness against B.1.351 was 10.4% ( 95% CI -76.8 to 54.8), reported Shabir Madhi, PhD, from the University of the Witwatersrand in Gauteng, South Africa, and colleagues, at New England Journal of Medicine.

Previously, the combined efficacy data of the AstraZeneca vaccine from the United Kingdom, Brazil and South Africa, before the appearance of B.1.351, showed an overall efficacy of 66.7% (95.8% CI 57.4-74.0) , as well as 74.6% effectiveness against the so-called United Kingdom variant, B.1.1.7.

From June 24 to November 9, 2,026 HIV-negative adults, aged 18-65, in South Africa were randomized to receive two standard doses of vaccine or placebo administered 21-35 days apart. The primary endpoint was safety and efficacy against COVID-19 confirmed in the laboratory more than 14 days after the second dose, while a secondary endpoint examined the efficacy of the vaccine against variant B.1.351.

The average age of the participants was 30, about 56% were men and 71% were black Africans. Almost 20% of the participants were obese, 42% were smokers and about 3% each had hypertension or chronic respiratory problems. The average time between doses was 28 days.

Overall, 23 out of 717 in the placebo group (3.2%) and 19 out of 750 in the vaccine group (2.5%) developed mild to moderate disease. Adults with COVID-19 received a nasal swab and 41 of 42 were sequenced, revealing that 39 cases were of variant B.1.351.

Regarding the secondary result of protection against COVID-19 disease of variant B.1.351, the authors observed, “the study was developed for the main objective of a vaccine effectiveness of at least 60% in preventing COVID-19 from any severity, regardless of variants. “

Madhi’s group also noted that there were no cases of hospitalization due to severe COVID-19 in either group, but because of the demographic and clinical profile of the participants, “the trial results are inconclusive” with respect to whether the vaccine protects or not against serious diseases of variant B.1.351.

Exploratory analyzes found approximately 33.5% efficacy (95% CI -13.4 to 61.7) against COVID-19 of any severity more than 14 days after the first dose.

Despite these results, the authors said that deliberations about the usefulness of this vaccine “need to be made in the context of the continued global spread and community transmission of variant B.1.351” and other strains with similar mutations.