GBS is a relatively common germ that is rarely dangerous to adults, but can be life-threatening to newborns. An estimated 10 percent to 30 percent of pregnant women carry the bacterium. It's the most frequent cause of sepsis and meningitis in newborns; it easily latches on to birth tissues, infecting babies that come into contact with the germ before or during birth.
About three of every 10,000 babies born in the United States contracted GBS in 2004, according to the U.S Centers for Disease Control and Prevention.
"The good news is that mortality is only 5 percent," Baker said. "This is a high mortality -- one in 20 babies die -- but it used to be 50 percent."
Half of all infants who develop meningitis through Group B strep suffer lasting neurologic damage that can include cerebral palsy, sight and hearing loss, mental retardation, learning disabilities and seizures, according to the March of Dimes.
Current treatment involves early detection through screening, followed by intravenous antibiotics administered to the mother prior to birth. This is part of a new protocol issued by the CDC in 2002 to help cut down on the number of babies infected by GBS.
However, the antibiotic needs to be administered at least four hours prior to delivery if doctors want to be sure of killing off the bacteria. Women sometimes don't arrive at the hospital early enough to start their IV antibiotics, Baker said. Children born prematurely before their mothers have received the screening also run the risk of exposure to GBS.
"We need to figure out better techniques to prevent even greater numbers of babies from getting infected," said Dr. James A. McGregor, visiting professor of clinical obstetrics and gynecology at the University of Southern California Keck School of Medicine in Los Angeles.
Doctors have been researching a way to prevent GBS through a vaccine administered to either pregnant women or women of childbearing age, but those efforts have stalled, Baker said.
Such a vaccine would work by introducing GBS-resistant antibodies into the mother that would then be passed on to the child during pregnancy. A decade-long collaborative study between Baylor and Harvard University and funded by the National Institutes of Health prepared such vaccines, and a small pregnancy trial found them to be safe and effective, Baker said.
But no drug company has stepped forward to mass-produce the vaccine, she said.
"It was the hope of the NIH that 10 years of work would result in a pharmaceutical company picking up the vaccine and developing it. That has not happened, and there is only one reason why," Baker said. "They don't want to give a vaccine to pregnant women. This is all about having too many lawyers in the United States," she said.
Pregnancy is so personal and so rife with complications that the companies are concerned they will be sued, she added. "Everyone's worried about litigation," Baker said. "They want legislation protecting them before they develop any vaccines."
With no vaccine imminent, doctors are trying to limit GBS infection by urging obstetricians and midwives to not strip the birth membranes, McGregor said. It's a traditional thing to do to induce labor, but it puts the Group B strep right up into the uterus," he said.
Another technique being investigated is treating babies right after birth with a shot of intramuscular penicillin, McGregor said. |
