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. One Aspect The study examined only one aspect of protection, J&J said in an email, and didn’t consider long-lasting responses among immune cells stimulated by its vaccine. “The data do not speak to the full nature of immune protection" from the shot, spokesman Jake Sargent said.
J&J’s vaccine has been shown to produce a strong immune response that lasts at least eight months after immunization, he said.