Ebola vaccine test trials may begin as early as January, according to the World Health Organization.

The WHO reported that the Ebola outbreak has infected over nine thousand people and killed over four thousand. West African countries, Liberia, Sierra Leone and Guinea are the three countries most affected by the virus.

According to USA Today, The Centers for Disease Control and Preventions has estimated that Ebola could affect up to 1.4 million people by January if the outbreak is not controlled. Experts say that vaccines may be the best hope for getting Ebola under control. Scientists are already starting to test vaccine candidates.

The vaccine study was developed first in September at the National Institutes of Health in Bethesda, Md. Studies have also began in the United Kingdom and Mali.

The New York Times reported that Johnson & Johnson announced that it will donate $200 million to the program. Chief Scientific Officer of Johnson & Johnson, Dr. Paul Stoffels said, "Typically, you don't make hundreds of thousands of vaccines before you know what the safety and immunogenicity is. This time, we will do that."

Johnson & Johnson expects to begin safety trials in January and produce one million doses in 2015.

The vaccines have already shown to provide protection against Ebola in animal testing. About 250 healthy adult volunteers will undergo testing so far in the US, Africa and Europe.

This year's Ebola outbreak marks the largest in history. Signs of the virus were found in Nigeria and Senegal in the past, but it has since then mutated. There are no further spreads in those countries.

A man in Dallas Texas was the first Ebola patient recorded in America. The CDC reported that it is taking precautions to prevent the further spread of Ebola within the United States. As a result, the CDC is working with other U.S. government agencies, the WHO and international partners to combat Ebola.