Dutch drug manufacturer Janssen Pharmaceutical Companies started testing an Ebola vaccine on humans this week. The Johnson & Johnson subsidiary produced 400,000 doses of the vaccine for large-scale clinical trials that could launch by April, the firm said in a statement.

“A total of 2 million regimens will be available through the course of 2015, with the ability to quickly scale up to 5 million regimens, if required, over a 12- to 18-month period,” Johnson & Johnson revealed.

The Oxford Vaccine Group at the University of Oxford’s pediatrics department is running the drug trial, with recruitment already underway. Researchers expect to complete patient selection by the end of the month, “and the first volunteers have received their initial vaccine dose.”

It would take about 100,000 vaccine doses to protect outreach workers and first responders, and as much as 12 million doses to cover adults in the most affected part of Africa.

"Through the unprecedented collaboration among the global health community, our goal is to bring this vaccine to families and frontline health care professionals as fast as possible,” said Dr. Paul Stoffels, the company’s Chief Scientific Officer and global pharmaceutical chairman.

"As a leader in the field of global health, we have a responsibility to act swiftly as Ebola continues to cause suffering among patients, families and health care workers in West Africa," said Johnson & Johnson chief Alex Gorsky.

Clinical studies will also be conducted in the United States and Africa beginning in January.

The United States National Institutes of Health is working with Janssen-owned firm Crucell Holland B.V. and Bavarian Nordic in Denmark.