Last week the FDA Allowed Johnson & Johnson Adenovirus-DNA in One Swipe vaccine in the United States for Covid-19, adding this option to the two mRNA vaccines (Pfizer / BioNTech and Moderna) already authorized in December. Its authorization is a huge public health victory for our country. But in the days that followed, the Johnson & Johnson vaccine somehow received a bad rap compared to its competition.
Unlike mRNA vaccines that first came to the market, the Johnson & Johnson vaccine is a Non-Replicative Human Adenovirus-DNA Vaccine, which means it works with proven technology that is more familiar to the public and has few side effects. That’s not to say, however, that this vaccine is low-tech, and somehow inferior. Cursive titles Johnson & Johnson trial results often cite an overall effectiveness of 66 percent, which, compared to the effectiveness rates of Pfizer and Moderna, may appear suboptimal. But a closer look at the trials and their results reveals significant context for that number – and that Johnson & Johnson’s single-dose vaccine offers equal protection to mRNA vaccines under certain circumstances. It was also the only vaccine of the three to show high protection against serious diseases of the circulating variants during its trials, as testing was done after many were already widespread. So while it may not have had the same effectiveness as mRNA vaccines against mild disease in this initial evaluation, this new vaccine is no less worthy of your arm.
First, let’s take a look at the strengths of the Johnson & Johnson trials themselves. Importantly, its Phase III trial population was more diverse among racial / ethnic groups and co-morbidities than the Pfizer or Modern testing. The level of trial diversity is not only important for evaluating efficacy, but also for gaining the trust of the communities represented in the trials. In the Johnson & Johnson trial, just over a fifth of participants were 65 years of age or older, and 40% had at least one comorbidity that may predispose to serious illness. Of the 43,783 participants enrolled, 62.1% were White, 17.2% Black or African American, 8.3% Native American or Alaskan native, and 3.5% Asian; 45.1 percent of the participants were Hispanic / Latino. In contrast, participants in the Pfizer and Moderna trials were 82.9% and 79.2% white, respectively.
Equally impressive were the results of Johnson & Johnson’s trial. Phase I and II trials of the vaccine provided strong data on the immunogenicity or ability of the vaccine to induce an immune response, a response that was found to increase over time beyond one month. It was also found to protect 100% of the time against hospitalization or death related to Covid-19. Specifically, there were 16 Covid-19-related hospitalizations and seven deaths among those who received the placebo, and no Covid-19-related hospitalizations or deaths among those who received the vaccine. In addition, the vaccine’s efficacy against severe illness two to four weeks after vaccination was 85.7%, although events of severe illness (without requiring hospitalization) were rare. And since the serious illness generated by SARS-CoV-2 is what caught the attention of the World Health Organization and around the world in the first place, to “defuse” it or drastically reduce its ability to make people critically ill is the most important benefit of all of our vaccines, including Johnson & Johnson.
Perhaps even more important to note, given our current race against the variants, is that the efficacy of the Johnson & Johnson vaccine against serious disease was the same in regions with high percentages of circulating variants, such as the ‘South Africa and Brazil. However, the effectiveness of the vaccine against milder diseases requiring no medical attention varied from region to region. This is probably the result of varying prevalence; protection against mild illness was 72 percent in the United States, 64 percent in South Africa, and 68 percent in Central / South America. This is of course where the Johnson & Johnson single dose vaccine compares unfavorably with mRNA vaccines, where the efficacy for severe outcomes was also essentially 100% and the efficacy for milder diseases over the course of the year. test was greater than 94%.