Johnson & Johnson announced Tuesday that new research shows two doses of itsvaccine offer stronger protection against the disease.
A booster shot two months after receiving the drugmaker's one-dose vaccine is 94% effective against the coronavirus, the company said, pointing to the results of a late-stage study that looked at antibody responses in adults between the ages of 18 to 55. The findings have not yet been peer-reviewed by scientists.
"Our single-shot vaccine generates strong immune responses and long-lasting immune memory," Dr. Mathai Mammen, global head of Janssen Research & Development at J&J, said in a statement. "And, when a booster of the Johnson & Johnson COVID-19 vaccine is given, the strength of protection against COVID-19 further increases."
Johnson & Johnson said in January that its single-shot vaccine isCOVID-19 and 85% protective against the most serious symptoms.
The company said it is in talks with the Food and Drug Administration, European Medicines Agency and other regulators about using booster doses of its vaccine.
Johnson & Johnson's study results come as the U.S. seeks to halt the spread of the highly contagious Delta variant. COVID-19 has killed, roughly as many as died during the 1918-19 Spanish flu pandemic.
A panel of outside experts for the U.S. Food and Drug Administration has recommended an emergency use authorization for afor some Americans — people 65 and older or those at risk of serious disease — six months after completing their first two doses. Other countries including Israel, France and Germany have also begun offering third vaccine doses to some people.
Contingent on FDA approval, the Biden administration has advanced a plan for the government to administer booster shots for adults who received their second shot of the Pfizer-BioNTech or Moderna vaccines at least eight months ago.
The Associated Press contributed to this report.