Johnson & Johnson announced that its single-dose COVID-19 vaccine produced strong, long-lasting protection against the rapidly spreading Delta variant and other highly prevalent SARS-CoV-2 viral variants. Furthermore, the data showed that the immune response’s durability lasted at least eight months, the longest time evaluated to date.

Though the study only included a small number of people and has yet to be peer-reviewed, it suggests that the Johnson & Johnson vaccine, like the Pfizer and Moderna vaccines, may provide a buffer for the United States against the highly transmissible variant. The findings were submitted to the preprint server bioRxiv as two separate studies.

The delta variant (B.1.617.2) was discovered in India in October 2020, and the World Health Organization designated it a “variant of concern” in May 2021, as previously reported by Live Science. The variant has spread to at least 92 countries, prompting the implementation of new COVID-19 restrictions in some areas.

The delta variant now accounts for more than 90% of newly diagnosed cases in the United Kingdom and more than 20% of new cases in the United States. Delta is thought to be approximately 60% more transmissible than the alpha variant, which was discovered in the United Kingdom and is currently dominant in the United States. 

According to a recent study, Pfizer’s COVID-19 vaccine was 88 percent effective against symptomatic disease caused by the delta variant, while AstraZeneca’s vaccine was only 60 percent effective and Moderna’s COVID-19 vaccine is very similar to Pfizer’s vaccine (both are mRNA vaccines), experts believe it will provide comparable protection. However, it was unclear how effective Johnson & Johnson’s vaccine would be against the delta variant.

Some experts predicted that the Johnson & Johnson vaccine would provide similar protection against delta as the AstraZeneca vaccine because they use the same platform. However, there are some differences between the two vaccines, the most significant of which is that Johnson & Johnson’s vaccine is administered in a single dose, whereas AstraZeneca’s is administered in two doses.

The new information is the result of two separate analyses. The first study examined data from eight participants who took part in the company’s phase 3 trial. They found that the vaccine produced neutralizing antibody immune system cells that bind to the virus and inactivate it before it can infect cells.

The second study examined data from 20 people who took part in an earlier clinical trial testing the vaccine. They discovered that the Johnson & Johnson vaccine provides at least eight months of protection against SARS-CoV-2 and generates “neutralizing antibodies against a range of SARS-CoV-2 variants of concern,” including delta variant.

Both Moderna and Pfizer have previously stated that their vaccine protects for at least six months. According to a small new study, mRNA vaccines could protect for years if the delta variant does not evolve significantly.