ATLANTA (AP) _ The government is recommending that doctors temporarily stop giving children a diarrhea vaccine because at least 20 infants have developed a bowel obstruction after getting their shot.

The Centers for Disease Control and Prevention said Thursday that RotaShield, the vaccine against rotavirus, has not been conclusively linked to bowel obstruction, but early studies show it may increase the risk.

The obstruction occurs when one part of the bowel becomes enfolded within another. Symptoms include vomiting, bloody stools and abdominal pain. Surgery is often needed to clear the blockage if it isn't caught early.

The CDC recommended suspending use of the vaccine in all children _ including those who have begun the three-dose series _ until November so health officials can conclude additional studies. Following the CDC's move, the American Academy of Pediatrics issued the same recommendation.

``It's enough to make us worry,'' said Dr. Melinda Wharton, head of the CDC's child vaccine preventable diseases branch. ``We're fortunate that rotavirus is a seasonal disease so we can postpone vaccination for a few months.''

Rotavirus, an intestinal infection, is the leading cause of severe diarrhea in children under 5 in the United States. Each year, an estimated 3 million American children are sickened, 50,000 are hospitalized, and 20 die. The disease primarily occurs in the winter and spring.

The vaccine's manufacturer, Philadelphia-based Wyeth-Ayerst Laboratories, said 1 million infants have been vaccinated with RotaShield since it received government approval in August. The three-dose series is given at ages 2 months, 4 months and 6 months.

Before its approval by the Food and Drug Administration, five cases of the bowel obstruction were reported for every 10,000 vaccine recipients.

As a result, the bowel obstruction was listed as a potential adverse reaction on the package insert. The CDC said it is still investigating, but based on the early findings so far, it appears that the bowel obstruction rate may be higher than expected.