The two new vaccines are still experimental, and will not be ready to be tested in people for at least two years. If human trials are successful, products might be ready for licensing five or six years from now, the researchers said. The vaccines would not be used for routine immunization, but would be given to health workers in high risk areas, virus researchers and people who had been exposed to the disease, such as relatives and others in close contact with sick patients. Eventually, it might be possible to combine the vaccines to protect people from both diseases with a single shot.

The new vaccines are not the first to protect monkeys. An earlier one, first proved in 2003, may go into safety studies in people in the United States later this year. Each vaccine has its advocates, and researchers say it is advantageous to have several candidates on the horizon.

The work described in Nature Medicine today was done by scientists from the United States and Canada, led by Dr. Steven M. Jones and Dr. Heinz Feldmann of the Public Health Agency of Canada in Winnipeg, and Dr. Thomas W. Geisbert of the United States Army Medical Research Institute of Infectious Diseases in Fort Detrick, Md.

Dr. Jones said the goal of the research was to provide a vaccine that could be used to stop outbreaks like the one in Angola or to protect people from germ warfare. He and other researchers said that governments and the military developed a strong interest in making vaccines against Ebola and Marburg during the 1990's after a Soviet defector said that Russians had stockpiled the Marburg virus, weaponized it and packed it into warheads for possible use in attacks on cities or battlefields.

"Marburg and Ebola are not as significant threats as smallpox would be, but one could wreak incredible human health tragedies in this country and could probably create a huge economic burden even if the diseases didn't spread like wildfire," said Dr. Peter B. Jahrling, an author of the article and an expert on viruses and bioterrorism who used to work for the Department of Defense and is now a chief scientist at the National Institute of Allergy and Infectious Diseases, of the National Institutes of Health. "But I think a lot of people here also see the humanitarian aspects of providing vaccine to people who need it."