Johnson & Johnson’s coronavirus vaccine is reporting a strong immune response, and it is one of the rare developing vaccines with no side effects so far.

After finishing the Phase 1/2a of the testing, the vaccine shows a high immune response in all of the 800 participants.

Two age groups were part of this vaccine trial, including 18- to 55-year-olds and 65 and older.

Both groups were tested for side effects and were given different doses.

The participants from the age group 18-to 55 from the two different doses developed antibodies to coronavirus in 29 days after receiving the first shot.

Over 99% of them had a strong immune response and can proceed to the next level of testing.

Johnson & Johnson’s coronavirus vaccine is called Ad26.COV2.S, and it is developed with the same technology as the company’s Zika, Ebola, and HIV vaccines.

Phase 3 trials will include over 60,000 adults in the U.S. and internationally, operating on 200 testing sites.

The purpose of the Phase 3 trial is to examine the effectiveness of a single dose of the vaccine, and it will also include volunteers who will receive a placebo.

Johnson & Johnson’s coronavirus vaccine trial is the only one in the U.S. that conducts Phase 3 with a single dose.