The Johnson & Johnson coronavirus vaccine provides immunity that lasts at least eight months, and it appears to provide adequate protection against the worrying Delta variant, the company said in a statement Thursday night (July 7)."Current data for the eight months studied so far show that the single-shot Johnson & Johnson COVID-19 vaccine generates a strong neutralizing antibody response that does not wane; rather, we observe an improvement over time," Dr. Mathai Mammen, head of research and development at J&J's Janssen vaccine arm, said in a statement, CNN reported.
The company said one dose of the vaccine elicits both a lasting antibody response and generates immune cells called T-cells that last eight months, also.
Dr. Dan Barouch of Beth Israel Deaconess Medical Center and Harvard Medical School and colleagues tested blood taken from 20 volunteers in an early stage, Phase 1/2 trial of the vaccine.
"Data showed that T-cell responses -- including CD8+ T-cells that seek out and destroy infected cells -- persisted over the eight-month timeframe examined,"
Pfizer/BioNTech and Moderna have both said their two-dose vaccines are protective for at least six months and researchers at Washington University in St. Louis reported earlier this week that their studies of vaccinated volunteers indicate protection from the vaccines should last much longer than that-- even for years. They did not test the J&J vaccine.
Earlier Thursday, J&J said a second or booster dose of its vaccine would not be necessary.