By the end of the year, the number of smallpox vaccine doses is likely to top 200 million as production efforts in the US have increased in the wake of 2001's terrorist attacks, according to the Centers for Disease Control and Prevention (CDC).

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

Two new vaccine sources are being produced by Cambridge, UK-based Acambis. Initially, the contract called for 40 million doses of one of the vaccines, Acam1000. But after the terrorist attacks, production was increased to about 55 million doses per calendar year.

This contract is for 20 years, so it is going to be the national backbone for vaccine supply for the next 20 years.

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

The Acam vaccines are under investigational new drug status. Phase 2 trials of both will end in October of this year, and LeDuc said licensure is expected in late 2003 or early 2004.

One existing source of the vaccine is Dryvax, produced by Wyeth, which contributes roughly 15 million doses when diluted one to one, and about 75 million doses at a 1:5 dilution.

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

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

National pharmaceutical stockpile sites are up and running, and plans are in place to deliver the final product from the stockpile to all cities with populations over 10,000.

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. Nobody under 30 has received it and no recently trained healthcare providers have ever administered it.

According to Hughes, the ACIP smallpox working group will make recommendations on June 20th about use of the vaccine both before and after exposure to the virus.

CDC's Advisory Committee on Immunization Practices May 9, 2002 Atlanta, GA