Image of gloved hand holding a vial of Johnson & Johnson's investigational COVID-19 vaccine

Johnson & Johnson’s single-shot COVID-19 vaccine prompts a “strong neutralizing antibody response” that lasts at least eight months, the drugmaker has announced.

Studies of eight months-worth of data show that the vaccine generates “persistent activity” against the worrisome Delta gene variant and other highly prevalent SARS-CoV-2 viral variants, the company said in a statement last week. The antibody response grows stronger over time, J&J officials said. What’s more, the company has observed that an additional response called cellular immunity also was “particularly robust [and] durable.”

Some long-term care residents and staff began receiving the J&J vaccine in the spring after the federal government made a switch from supplying designated pharmacists with the Pfizer and Moderna vaccines. Those drugmakers’ shots were authorized for use in the United States in December, whereas the J&J shot received authorization in late February.

Image of Paul Stoffels, M.D., chief scientific officer, J&J
Paul Stoffels, M.D., chief scientific officer, J&J

Use of the drug then was paused briefly in early April while officials investigated rare reports of blood clots in recipients. The halt temporarily threatened vaccination efforts in U.S. nursing homes and assisted living communities. 

To date, the only studies on lasting COVID-19 vaccine efficacy have been vaccines that use groundbreaking mRNA technology. The J&J vaccine uses more traditional virus-based technology. 

The new study results should be encouraging to those who have received the J&J vaccine, an investigator told the New York Times. 

“There was a lot of misinformation that was spreading, so we decided that we needed to get this into the public domain right away,” he told the news outlet.

“This adds to the robust body of clinical data supporting our single-shot vaccine’s ability to protect against multiple variants of concern,” Paul Stoffels, M.D., J&J’s chief scientific officer, said in a statement.