J&J Shot Performs Poorly Against Delta Variant

The laboratory study, released on the preprint server bioRxiv, hasn't been published in a peer-reviewed journal and focuses on one key portion of the immune response, called neutralizing antibodies.

Johnson & Johnson's single-dose Covid vaccine produced relatively low levels of antibodies against the delta variant in a study, raising questions about how well the shot will hold up against the strain that accounts for the vast majority of U.S. cases. The laboratory study, released on the preprint server bioRxiv, hasn't been published in a peer-reviewed journal and focuses on one key portion of the immune response, called neutralizing antibodies. New York University scientists found that J&J's vaccine produced roughly five-fold lower levels of the protective antibodies against the delta variant compared to the levels raised against an early coronavirus strain. The delta variant accounts for 83% of genetically sequenced cases in the U.S., Centers for Disease Control and Prevention Director Rochelle Walensky said Tuesday in a Senate hearing. While two-dose messenger RNA vaccines from Pfizer Inc. and Moderna Inc. also produced fewer antibodies against the highly transmissible delta strain, the reduction was less dramatic, the study found. Compared to two shots of mRNA vaccines, the single-shot J&J vaccine "showed a more pronounced decrease in neutralizing titer against the variants, raising the potential for decreased protection," the researchers from NYU researchers said in the study.