Johnson & Johnson (NYSE:JNJ) has moved into phase 3 development of its coronavirus vaccine candidate, which goes by the code name JNJ-78436735. The study, called Ensemble, will enroll up to 60,000 volunteers across three continents.

The company trails Moderna (NASDAQ:MRNA), AstraZeneca (NYSE:AZN), and the duo of Pfizer (NYSE:PFE) and BioNTech (NASDAQ:BNTX), which are all in the process of finishing up enrollment in phase 3 clinical trials for their own COVID-19 vaccine candidates. It may also take Johnson & Johnson longer to reach full enrollment in its study given its larger size. Moderna plans to enroll 30,000 people in its trial, while AstraZeneca is shooting for 50,000 across multiple phase 3 studies, and Pfizer and BioNtech recently announced that they had increased their enrollment target from 30,000 to 44,000.

Doctor giving a shot to a boy holding a stuffed animal

Image source: Getty Images.

While Johnson & Johnson may lagging behind the pace-setters in this race, its one-dose format would give it a huge advantage over the leading vaccine candidates, all of which require a booster shot three to four weeks after the initial vaccination. The company is planning on running a separate phase 3 study to see whether two doses of JNJ-78436735 provide stronger protection than one, but the immune responses in participants receiving just one dose in the phase 1/2a study looked solid enough to continue testing under that dosing regimen.

The one-shot format will also mean that Johnson & Johnson will be able to get initial efficacy data more quickly -- measured from the start of enrollment to readout -- because it won't have to wait until trial participants get booster shots before starting to count cases of COVID-19 among them.

Johnson & Johnson says it hopes to have enough data from the study to allow it to gain FDA emergency use authorization for the vaccine in early 2021. Investors should keep in mind that the healthcare conglomerate has committed to selling JNJ-78436735 on a not-for-profit basis, so regardless of how it might ultimately fare in the COVID-19 vaccine market, it won't affect the company's earnings.