WASHINGTON, Aug. 5 (UPI) -- The U.S. Army should look at whether the anthrax vaccine is behind the unexplained cluster of pneumonia cases among soldiers in Iraq, according to the co-author of a government-sponsored study that last year found the vaccine was the "possible or probable" cause of pneumonia in two soldiers.

Dr. John L. Sever of George Washington University Medical School told United Press International Tuesday that he expects the military to consider the anthrax vaccine, among other possibilities, as it investigates pneumonia among soldiers in and around Iraq, where troops have been widely vaccinated against anthrax.

The Pentagon announced Tuesday it is investigating 100 cases of pneumonia among soldiers in Iraq and southwestern Asia. Two have died. Fifteen have had to be placed on respirators.

"As physicians, I would think they would be looking at all possible causes. I would think vaccines would be part of that," said Sever, a medical professor at George Washington who was one of six authors of the study. Col. Robert DeFraites from the Army Surgeon General's office told reporters at the Pentagon briefing Tuesday that biological warfare -- including smallpox or anthrax -- was unlikely to be the cause of the pneumonia. He did not mention vaccines as a possible cause, and the issue was not raised by reporters.

DeFraites and spokeswoman Virginia Stephanakis of the Army Surgeon General's office did not return calls Tuesday asking whether the Pentagon was looking into a possible vaccine connection.

Sever said the anthrax vaccine study, printed in the May 2002 issue of Pharmacoepidemiology and Drug Safety, found that the vaccine was the "possible or probable" cause of pneumonia among two soldiers. The Department of Health and Human Services convened the group, called the Anthrax Vaccine Expert Committee, which studied 602 reports of possible reactions to the vaccine among nearly 400,000 troops who received it, Sever said.

In addition to identifying pneumonia and flu-like symptoms among troops who received the vaccine, the group also looked at four other cases of potentially serious reactions, including severe back pain and two soldiers who had sudden difficulty breathing in a possible allergic reaction to the vaccine.

Sever described the two cases of pneumonia as "wheezing and difficulty breathing going into a pneumonia-like picture."

To conduct the study, the Anthrax Vaccine Expert Committee examined reports from the U.S. military to the Centers for Disease Control and Prevention; they are anecdotal reports and do not necessarily show a cause-and-effect relationship.

DeFraites said the two deaths under investigation by the Army Surgeon General occurred in June and July and that both soldiers had been in Iraq. He said the investigation began as soon as the first death occurred. In a case apparently not included in that total, 22-year-old Army specialist Rachael Lacy of Lynwood, Ill., died at the Mayo Clinic in Rochester, Minn., on April 4 of what one doctor diagnosed as pneumonia, after receiving anthrax and smallpox vaccinations but without ever having been deployed.

Dr. Eric Pfeifer, the Minnesota coroner who performed the autopsy, told the Army Times that the smallpox and anthrax vaccines "may have" contributed to her death. "It's just very suspicious in my mind...that she's healthy, gets the vaccinations and then dies a couple weeks later." He listed "post-vaccine" problems on the death certificate.

Moses Lacy, Rachael Lacy's father, told the Army Times that she called in March and said she had chest pains and breathing problems and had been diagnosed with pneumonia.

One service member who was deployed to Kuwait and received the four-shot anthrax series told United Press International Tuesday he developed bronchitis and a severe cough after receiving his shots, and that about a fifth of the troops he was deployed with had similar symptoms and were prescribed medicine to treat them. His symptoms continued after he returned to the U.S., and he sought further treatment at a base clinic. He got better, but believes he nearly came down with pneumonia.

The Pentagon dispatched two teams to look into the pneumonia: one to Iraq and another to a U.S. military base in Landstuhl, Germany, where some sick soldiers are treated.

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