Doctors target killer cough in new mothers
by Mary Helen Yarborough
This cough is so bad that it makes the sufferer vomit and can fracture a person’s ribs. Marked by a signature “whoop” at the end of the cough, pertussis is potentially deadly for infants and small children.
To stem the spread of this infectious disease, a team of physicians at MUSC has instituted a new protocol to increase pertussis immunization.
Pertussis, also called whooping cough, can be prevented through a vaccination that, since 2005, comes in a combination of inoculations—tetanus, diphtheria and pertussis (Tdap).
Tdap vaccine has few, if any, side effects other than the soreness at the site of the shot. It has been available to new mothers, patients and employees at MUSC, but not everyone has received the vaccination.
To boost the rate of immunization against pertussis, a multi-disciplinary team of physicians including Sandy Fowler, M.D., of the Pediatric Infectious Disease unit; David Soper, M.D., an OB/GYN; and Barry Hainer, M.D., of the Department of Family Medicine, implemented a new post-partum Tdap protocol that targets new mothers. Targeting post-partum mothers is important, because infants are most likely to acquire pertussis from their mothers.
Initial data reviewed by the MUSC Tdap team shows about 30 percent of post-partum mothers opted to have the vaccine. That is about equal to the percentage of cases that result from mother-to-infant transmission.
“We would like to see at least a 60 percent vaccination rate among post-partum mothers,” Hainer said. “So, we met with lead nurses on 5 East to look at ways to improve this process.”
The Hainer-Fowler-Soper protocol alters the approach nurses and doctors use to encourage mothers to get the vaccine, and include the following initiatives:
A child is particularly vulnerable to pertussis until after 6 months after the three-step pertussis vaccination series, at 2, 4 and 6 months of age, is completed. Boosters are then administered at 12 and 18 months, and between 4 and 6 years of age. Because the effectiveness of the vaccine wears off after six years, boosters are encouraged for adolescents and adults to prevent a population expansion of carriers.
Therefore, unvaccinated people can spread the pertussis bacteria without knowing it. Consequently, infants and unvaccinated children also can get the disease from their fathers, siblings, grandparents, child and health care workers, and others. About 75 percent of pertussis cases in children result from exposure to adult and adolescent carriers. Children then carry the disease with them to school, and it spreads.
Because pertussis is such a highly contagious disease, health care workers and school officials must report to the S.C. Department of Health and Environmental Control within 24 hours of a suspected case.
Unlike tetanus, a microorganism that thrives in soil and dirt, pertussis and diphtheria require a human host to survive, Hainer said.
“We want to attain ‘herd immunity,’ so that the whole herd, or population, is immune by virtue of the fact that enough members of the herd have been vaccinated,” Hainer said. “It’s like polio. When a significant number of people are vaccinated, you do not see any cases of the disease.”
MUSC also is encouraging all health care workers, especially those working with children and infants, to have the Tdap vaccination.
“There is no requirement for Tdap for adults, nor is there a requirement that health care workers receive Tdap, though this is encouraged and recommended by the U.S Centers for Diseases Control and Prevention,” Fowler said. “MUSC will have several Tdap days during September for employees.”
Because of the push, between 600 and 800 doses of the vaccine are estimated as having been distributed to employees.
Even if adults are not regularly exposed to children, adults can still transmit pertussis to other adults who do have exposure to children, Fowler said. In addition, studies of adults with chronic cough show that as many as 25 percent of these adults had pertussis. “Adults can become significantly ill with pertussis, as well,” Fowler said.
In China, it’s called the eight-week cough, Hainer added.
To receive a Tdap vaccine, go to MUSC Employee Health Services, 57 Bee St., weekdays from 7:30 a.m. to 3:30 p.m. No appointment is necessary. Information and vaccinations also can be obtained during MUSC Health 1st Wellness Wednesdays from 10:30 a.m. to 1 p.m. each Wednesday in September in the Children’s Hospital lobby.
In the summer of 2005, two infants died in South Carolina due to pertussis. Last month two infants were in the Pediatric ICU with pertussis. This disease is still a threat to infants, as well as adolescents and adults, despite introduction of a Tdap vaccine to boost waning immunity in adolescents and adults (with the idea of producing a cocoon immunization strategy).
Based on data collected in 2004-2005, 17 children were admitted to MUSC with pertussis, Fowler said. (The average cost per case is estimated at $48,000.) Using various models and assumptions, Fowler deducts that about a fourth of these cases likely resulted from maternal transmission.
“The post-partum Tdap program, alone, would have prevented four of these cases,” Fowler said. “The four prevented case-scenario comes from data that showed that the mother was the source of infection in about 25 percent to 30 percent of children with pertussis. Since the post-partum project is now only targeting mothers, this is the fraction of we could have expected to be prevented. Other adult family members served as the source for 25 percent of the cases.”
Friday, Sept. 5, 2008