What happened

Coronavirus stock Moderna (MRNA -2.45%) was up by nearly 8% in mid-afternoon trading on Thursday. Two pieces of news about the company's coronavirus vaccine seem to be supporting this rise.

So what

The first is Moderna's announcement that dosing of participants has begun in a phase 1/2 clinical trial for mRNA-1273 in Japan. This study, which is being led by Japanese pharmaceutical company Takeda (TAK -1.21%), seeks to enroll 200 people aged 20 and older.

Gloved hands holding a vial of medicine.

Image source: Getty Images.

If the vaccine proves as efficacious as it has in trials elsewhere in the world it is sure to be authorized for use in the country, which is home to over 127 million people. Takeda has agreed to distribute 50 million doses if and when authorization occurs.

The second bit of news comes from the United States. On Wednesday, California's Department of Public Health announced it was safe to use vaccines from a lot that had come under scrutiny after several people reportedly developed allergic reactions to their initial doses from the batch. Following that incident, the state paused inoculations from the lot.

Now what

Given mRNA-1273's performance in previous trials, it's almost a foregone conclusion that it will be successful in the Japanese study. And, since it's a two-dose vaccine, Japan will need far more than the initial 50 million doses that comprise the current Moderna/Takeda agreement. The restart of dosing from the affected lot in California also presages continued high demand for the vaccine.