A study from a lab at New York University posted online Tuesday suggests that the one-shot Johnson & Johnson COVID-19 vaccine is not as effective against the delta variant of the virus as it is against the original coronavirus.
According to the study’s authors, the results suggest that the more than 13 million who have received the Johnson & Johnson vaccine may need to get a second shot, preferably either the Pfizer-BioNTech or Moderna mRNA vaccine.
Experiments were conducted with blood samples in a laboratory, not using real-world reports or samples. The study, which was published in bioRxiv and has not yet been peer-reviewed.
Nathaniel Landau, a virologist at NYU’s Grossman School of Medicine, said researchers do not want to discourage people from getting the Johnson & Johnson vaccine, but urge them to supplement the vaccine for more protection against the highly contagious delta variant.
“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,” study leader Nathaniel Landau, a virologist at NYU’s Grossman School of Medicine, told The New York Times.
According to the study, the mRNA-based vaccines Pfizer and Moderna were 94 to 95% effective in preventing COVID-19 whereas the “adenoviral vector-based” Johnson & Johnson had a roughly 67% effective rate.
Johnson & Johnson spokesperson Seema Kumar told the Times that the study does “not speak to the full nature of immune protection.”
The company told CNBC that its data showed the vaccine “generated strong, persistent activity against the delta variant and other highly prevalent variants.”
Other, smaller studies published by Johnson & Johnson have suggested that a single dose of the vaccine is effective against the variant for up to eight months after inoculation.
In May, a study of the single-dose AstraZeneca vaccine showed it was 33% effective against the delta variant. The AstraZeneca vaccine is similar in structure to the Johnson & Johnson vaccine.
AstraZeneca was 60% effective after two doses, according to the study.
The delta variant is a mutation of the original COVID-19 virus and appears to be highly contagious. Currently, it is the predominant strain of the coronavirus in the United States.