WASHINGTON — Two military members recently showed “significant adverse effects” to the smallpox vaccine, though the symptoms are not life-threatening, defense officials said.

One of the two patients began showing the adverse signs over the weekend and the other on Tuesday, Army Lt. Col. John Grabenstein, deputy director for military vaccines, said Wednesday during a health conference.

Because the two cases are being reviewed, he declined to provide information such as the patients’ sexes, ages, whether they are deployed overseas or serving in the United States, active duty or guard or reserve, or give a general description of the side effects and what type of medical treatment the two are receiving.

However, once their case reviews are complete, which should occur within the next few days, Grabenstein said much of that kind of information would be made public, to include being posted on the Defense Department’s official smallpox Web site: www.smallpox.army.mil .

“We want the whole story correct the first time,” he said.

Since President Bush ordered on Dec. 13 a mandatory smallpox vaccination program that eventually will tap roughly 500,000 troops, about 3 percent of those vaccinated have lost one or more days at work or reported side effects such as fever or malaise, Grabenstein said. There have been no reported deaths.

To date, roughly 3,000 military health-care workers have gotten the vaccine. The number in the operational force is not releasable to the public, he said.

However, both the Center for Disease Control and Prevention and the Food and Drug Administration are updated weekly on the number and health status of vaccinated troops.

Targeted troops include those on emergency response teams, troops deployed to the front battle lines, and those living in high-risk areas of the globe. For security reasons, the high-risk areas are not being publicly identified.

It has been reported that troops deployed to the Middle East region have been vaccinated.

Side effects from the vaccine range from flulike symptoms to, in extreme cases, death. Experts have estimated that one to four people out of every million vaccinated could die from the vaccine.

In the past, about 1 in 1,000 vaccinated people experienced reactions that were serious, but not life-threatening, according to the Web site. Most reactions involved the spread of vaccine virus elsewhere on the body.

The vaccine is made from a live virus, and if the inoculation site is touched, and people touch another part of their body, it can spread.

Historically, roughly 30 percent of those exposed to the disease die.

And while the program is mandatory, some servicemembers with health conditions will be exempt, including those with compromised immune systems (such as those who are HIV positive), skin conditions like eczema, cancer patients, and women who are pregnant or breastfeeding.