J&J ‘one shot’ vaccine ineffective against Delta variant, study finds

pharmafile | July 21, 2021 | News story | Medical Communications, Research and Development  

A new study posted online on Tuesday, has found that Johnson & Johnson’s COVID-19 vaccine is much less effective against the Delta and Lambda variants, adding to the growing list of evidence that the 13 million people who have already been inoculated will have to receive a second dose.

The authors of the study recommended people should ideally receive one of the mRNA vaccines made by Pfizer-BioNTech or Moderna.

The study, which has not yet been pier reviewed, contradicts J&J’s smaller studies that were published this month which suggested that a single dose of the vaccine is effective against the variant even eight months after inoculation.

The results from this latest study, that relied upon laboratory testing, are consistent with efficacy levels seen from the AstraZeneca vaccine, which has a similar architecture to J&J’s jab. AstraZeneca’s vaccine is only 33% effective against symptomatic disease caused by the delta variant after one dose.

Nathaniel Landau, a virologist at NYU’s Grossman School of Medicine, who led the study, said: “The message that we wanted to give was not that people shouldn’t get the J&J vaccine, but we hope that in the future, it will be boosted with either another dose of J&J or a boost with Pfizer or Moderna.”

In the study, Landau and his colleagues looked at blood samples taken from 17 people who had been immunised with two doses of an mRNA vaccine and 10 people with one dose of the J&J vaccine.

The J&J vaccine started out with a lower efficacy than the mRNA vaccines and then showed a bigger drop in efficacy against the delta and lambda variants.

This new study has no ties to any of the vaccine manufacturers and has reported similar data to other studies in monkeys and humans that have shown greater efficacy with two doses of the J&J vaccine, compared with one dose.

Several studies have suggested that the mRNA vaccines made by Pfizer-BioNTech and Moderna will maintain their efficacy against the coronavirus, including all variants identified so far. One recent study showed, for example, that the vaccines trigger a persistent immune reaction in the body that may protect against the coronavirus for years.

It should be noted that data from J&J’s vaccine is more limited as it did not begin distribution until much later than other mRNA jabs. In fact, most studies of effectiveness of the coronavirus vaccines were conducted at medical centres and hospitals that relied on samples from staff members who received the mRNA vaccines.

Small studies published by researchers affiliated with J&J suggested that the vaccine was only slightly less effective against the delta variant than against the original virus, and that antibodies stimulated by the vaccine grew in strength over eight months.

Kat Jenkins

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