The results prompted the health care firm to begin human trials last week in Belgium and earlier this week in the U.S.
The U.S. government is backing J&J's vaccine effort with $456 million in funding as part of a spending spree aimed at speeding production of a vaccine to end the pandemic, which has infected millions and killed more than 660,000 people.
It says the vaccine prevented infection by providing complete or near-complete protection in the lungs from the virus in non-human primates in the pre-clinical study.
Tests have shown that the vaccine promotes the creation of protective antibodies.
Russian Federation is developing two vaccines to help cure the coronavirus, with clinical studies on more than 1,600 people planned before it enters large scale production.
The vaccine uses a common cold virus, called adenovirus serotype 26 (Ad26), to deliver the SARS-CoV-2 spike protein into host cells, where it stimulates the body to raise immune responses against the coronavirus.
The Philippines plans to buy 40 million doses worth $400 million for 20 million people, around a fifth of the country's 107 million population, the country's Finance Secretary Carlos Dominguez said.
"We now need to move into larger scale real-world trials, but it is good to see more data and more products moving into this very important phase of vaccine discovery". Around the same time, the company will start a parallel phase 3 study testing a two-shot regimen of the vaccine, Stoffels said. Six weeks after the immunization, all animals were exposed to SARS-CoV-2.
Of the six animals that received the optimal vaccine candidate, Ad26.COV2.S, none showed the virus in their lungs, and only one animal showed low levels of virus in nasal swabs.
Moreover, neutralizing antibody responses correlated with protection, suggesting that this biomarker will be useful in the clinical development of COVID-19 vaccines for use in humans.
J&J shares were up almost 2% at $149.72 before the bell on Thursday.