mRNA Neo-Vaccinoids Damn Near Worthless At Preventing Covid-21 Infection

FT  |  A rise in vaccinated people becoming infected with coronavirus has cast doubt over the lasting efficacy of Covid-19 vaccines, according to new studies, including one that found protection gained from the BioNTech/Pfizer shot declined more rapidly than that from the AstraZeneca jab. An Oxford university study published on Thursday found that the efficacy of the Pfizer vaccine against symptomatic infection almost halved after four months, and that vaccinated people infected with the more infectious Delta variant had as high viral loads as the unvaccinated. Two research papers from the US and Qatar have also fuelled debate over the need for top-up booster shots as they found higher numbers of “breakthrough infections” than anticipated, even though protection against serious cases of the virus appears to hold. Natalie Dean, a biostatistics professor at Emory University, said the spread of the Delta variant had made it “a lot harder” to stop transmission. “The situation has changed with respect to how far we think vaccines can take us,” she said. “We’ve been brought back to a more modest — but still critical — goal: to prevent severe disease, hospitalisations and deaths.” 

The Oxford scientists showed vaccine efficacy falling since the Delta strain became dominant in the UK in May. While the Pfizer shot was more effective at first, by four to five months after the second dose its efficacy was roughly the same as AstraZeneca’s jab, as the protection offered by the latter has barely budged. The paper’s authors were not involved in the creation of the AstraZeneca vaccine, which originated at Oxford university. Tomas Hanke, professor of vaccine immunology at Oxford’s Jenner Institute, speculated that the AstraZeneca shot generates longer-lasting immunity because its spike protein sticks around for more time, promoting a bigger immune response. “When you deliver RNA, like the Pfizer vaccine, you deliver a finite number of mRNA molecules which are eventually cleared from the system,” he said. “But when you deliver the adenovirus, as AstraZeneca does, you deliver a template which then keeps producing these mRNAs that then produce the spike protein, so there’s no ceiling.” A preprint based on evidence collected at the Mayo Clinic hospital chain in the US state of Minnesota showed protection against infection fell from 91 per cent to 76 per cent between February and July for the vaccine made by Moderna, and from 89 per cent to 42 per cent for the Pfizer jab.