"This will prevent us from finding ourselves in the same situation we were originally--with an antiquated vaccine and no production capability," said Dr. James LeDuc, Director of the CDC's Division of Viral and Rickettsial Diseases, referring to one of the major new contracts to produce 55 million doses a year of the vaccine.

The smallpox vaccine supply will come from four sources, two existing and two new, Dr. LeDuc said at the Advisory Committee on Immunization Practices (ACIP) smallpox working group meeting here.

Two new vaccine sources are being produced by Acambis (formerly OraVax; Cambridge, UK). Initially, the contract called for 40 million doses of one of the vaccines, Acam1000. But after the terrorist attacks, the amount of production was increased to about 55 million doses per calendar year, according to Dr. LeDuc.

"This contract is for 20 years, so it is going to be the national backbone for vaccine supply for the next 20 years," Dr. Le Duc pointed out.

Another vaccine also produced by Acambis, called Acam2000, will be produced as a one-time lot of 155 million doses.

Both of the Acam vaccines are under investigational new drug status. Phase II trials of both the vaccines will end in October of this year, and licensure is expected in late 2003 or early 2004, according to Dr. LeDuc.

Two existing sources of the vaccine are the Wyeth Dryvax product, derived from a seed virus of the New York City Board of Health (NYCBH) strain. This contributes about 15 million doses at a 1:1 dilution and about 75 million doses at a 1:5 dilution. A recent study published in The New England Journal of Medicine found the 1:5 dilution to be 100% effective (see Reuters Health report March 28, 2002.)

A second source is Aventis Pasteur's recently discovered 40-year-old smallpox vaccine supply, which will provide about 70 to 90 million doses.

Orders also call for delivery of bifurcated needles to administer each dose as well as 30,000 doses of vaccinia immune globulin, used to treat adverse reactions to the vaccine.

According to Dr. LeDuc, national pharmaceutical stockpile sites are up and running, and plans are in place to deliver the final product from the stockpile to all cities over 10,000 in population.

"There are 3556 such cities in the US, and we feel that we can get this product to those cities within 5 to 7 days," he said. "The challenge we are now facing is coordinating with the states where to deliver it."

In an interview with Reuters Health, Dr. James M. Hughes, Director of the CDC's National Center for Infectious Diseases, pointed out that there will be a major need for education of the public and health professionals about the vaccine.

"It's not a totally benign vaccine," he said. No one now under the age of 30 received it as a child, and "no recently trained healthcare providers have ever administered it," he pointed out.

According to Dr. Hughes, the ACIP smallpox working group will make recommendations on June 20th about pre- and post-event use of the vaccine.