Janssen’s Johnson & Johnson single-dose Covid vaccine may be much less effective against the Delta and Lambda variant of the SARS-CoV-2 coronavirus than the original strain. This is suggested by a new study, rebounded in the international media, according to which many of those who have received this shield product may have to consider a booster, a heterologous booster, ideally one of the mRna vaccines. The work, available online but not yet published in a scientific journal and therefore not yet peer-reviewed, comes to conflicting conclusions compared to other smaller studies published by J&J earlier this month, which instead suggest that a single dose of the vaccine is effective against the variant even eight months after inoculation.
The study led by Nathaniel Landau, a virologist at the Grossman School of Medicine in New York, is based on experiments conducted with blood samples in the laboratory – reports the ‘New York Times’ – and may not reflect the vaccine’s performance in the real world, but Its results, the experts note, are consistent with observations on a single dose of the AstraZeneca vaccine, which has a similar architecture and shows only about 33% efficacy against symptomatic disease caused by the Delta variant.
“The message we wanted to give – specifies Landau – is not that people should not receive the J&J vaccine, but we hope that in the future it will be enhanced with another dose” of the same product “or with a” heterologous “booster with Pfizer or Moderna. “. Other experts such as New York-based Weill Cornell Medicine virologist John Moore also think this should be considered a “two-dose vaccine.”
If Moore therefore defines credible the results of the new study carried out by a team that has no ties to any of the vaccine manufacturers, Seema Kumar, spokesperson for J&J, points out that the data from this work “do not speak of the full nature of immune protection. “.