Johnson & Johnson’s single-shot COVID-19 vaccine is still effective at least eight months out and also protects against the worrisome delta variant, the company said Thursday.

Johnson & Johnson announced the results of two studies on Thursday: In one, researchers used blood samples from eight participants in its clinical trial and found that the vaccine elicited neutralizing antibody activity against the delta variant. 

Doctors and epidemiologists around the world are concerned about the variant because it’s more easily transmissible than other strains of the coronavirus. In the U.S., the delta variant, which was first detected in India, now accounts for about a quarter of new infections, and health officials believe it will become the country’s dominant strain in a matter of weeks.

In the second study, scientists found that immune responses generated from the Johnson & Johnson vaccine lasted at least eight months. In fact, the researchers found that the neutralizing antibodies had increased over time. That also applied to variants of concerns, including delta.

"Today’s newly announced studies reinforce the ability of the Johnson & Johnson COVID-19 vaccine to help protect the health of people globally," Johnson & Johnson Chief Scientific Officer Dr. Paul Stoffels said in a news release.

"We believe that our vaccine offers durable protection against COVID-19 and elicits neutralizing activity against the Delta variant," Dr. Stoffels continued. "This adds to the robust body of clinical data supporting our single-shot vaccine’s ability to protect against multiple variants of concern."

Dr. Mathai Mammen, global head of Johnson & Johnson’s Janssen Research & Development unit, added, “With each new dataset, we build on our solid foundation of evidence that our single-shot COVID-19 vaccine plays a critical role in ending the pandemic, which continues to evolve and pose new challenges to global health.”

Both studies, which have not yet been peer-reviewed, have been submitted to bioRxiv, a website for unpublished preprints of medical research.

Johnson & Johnson is one of three vaccines currently authorized for emergency use in the United States, although its 12.3 million shots account for less than 8% of the full vaccinations in the country.

The other vaccines in the U.S. also have shown to be effective against the delta variant. A Pfizer official in Israel said last month that its vaccine appears to be around 90% effective against the strain. And Moderna reported this week that a lab study showed its vaccine, too, produces neutralizing antibodies against delta.

With the delta variant spreading — and infections on the rise again in the U.S. — health officials are urging Americans who have not yet been vaccinated to do so.

“The good news we have is that we have a solution,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and President Joe Biden’s chief medical adviser, said Thursday. “The science is clear. The best way to protect yourself against the virus and its variants is to be fully vaccinated.”