Giving whooping cough vaccine earlier has benefits

NEW YORK (Reuters Health) - Vaccinating children against whooping cough at 6 weeks of age rather than at 2 months could markedly reduce the number of cases seen each year in the US and help prevent serious complications, new research suggests.

Whooping cough -- known medically as pertussis -- is a highly contagious respiratory infection that causes uncontrollable attacks of coughing and breathlessness. Before a vaccine became available, whooping cough was a major, sometimes fatal childhood disease.

To prevent whooping cough, infants and children receive five doses of the DTaP vaccine, which also protects against diphtheria and tetanus. The first dose is currently given at age 2 months.

"Rates of pertussis, which can be life-threatening in young infants, are increasing," study investigator Dr. Timothy R. Peters, from Wake Forest University School of Medicine in Winston-Salem, North Carolina, said in a statement.

"Pertussis vaccine has been highly effective in defending children against this disease, and we find that modest adjustments in the timing of vaccine administration may offer enhanced protection to very young infants who are especially susceptible to severe disease," he added.

Using published data on pertussis rates in the US from 1990 to 1999, the research team estimated rates of the disease and related hospitalizations and deaths in the infant population in 2004. The team then estimated the impact of moving the first dose of the DTaP series up from 2 months to 6 weeks.

The investigators calculate that 1,236 cases of pertussis, 898 hospitalizations, and 7 deaths due to pertussis would be averted each year by accelerating DTaP administration. This translates into a 9 percent reduction in cases, a 9 percent drop in hospitalizations, and a 6 percent fall in pertussis-related deaths for infants younger than 3 months of age.

If the second and third doses of DTaP were moved up by 2 weeks, they estimate that an extra 923 cases of pertussis, 520 hospitalizations, and 2 deaths would be prevented each year.

"While two weeks may seem negligible, this change would reduce the time that a 2-month-old infant is completely without pertussis vaccine protection by 25 percent," Peters noted.

"Because pertussis so greatly threatens very young infants, the benefit of earlier vaccination may result in a significant decrease in severe pertussis disease nationally, and may be an especially useful approach during outbreaks of pertussis."

SOURCE: Pediatrics, November 2008.