Johnson & Johnson have stopped the clinical trial for the coronavirus vaccine because of unexplained illness of its volunteers.

One of drugmaker that used for an advanced clinical trial of experimental coronavirus vaccine which is Johnson & Johnson have paused it due to the unexplained illness of its volunteers.

"Following our guidelines, the participant's illness is being reviewed and evaluated by the ENSEMBLE independent Data Safety Monitoring Board (DSMB) as well as our internal clinical and safety physicians," Johnson & Johnson said.

"Adverse events -- illnesses, accidents, etc. -- even those that are serious, are an expected part of any clinical study, especially large studies."

The company does not say what illness it is that affects the pause of the clinical trial. The means of having a clinical trial to know the side effects of a drug before it produces a lot. It is stopped or paused when unexplained illness happened and doctors check it whether it is because of the vaccine or not.

"Based on our strong commitment to safety, all clinical studies conducted by the Janssen Pharmaceutical Companies of Johnson & Johnson have prespecified guidelines. These ensure our studies may be paused if an unexpected serious adverse event (SAE) that might be related to a vaccine or study drug is reported, so there can be a careful review of all of the medical information before deciding whether to restart the study," the company said.

"We must respect this participant's privacy. We're also learning more about this participant's illness, and it's important to have all the facts before we share additional information," the company added.

Johnson's Phase 3 trial started in September. It's one of six COVID-19 vaccines bring and tested in the US, and one of four in the most advanced, Phase 3 stage. It is a candidate vaccine to use in the Philippines.