Too Few Shots for Pertussis Protection

Pertussis undervaccination puts children at higher risk for contracting the disease

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Cases of pertussis, or whooping cough, have been increasing in recent years in the US. The CDC recommends the pertussis vaccine to protect children and adults from the disease.

A recent study found that young children who had not received all their vaccine shots for pertussis were much more likely to catch the disease.

Pertussis, also known as whooping cough, involves a serious cough that can last for many weeks or months. Pertussis can also be fatal, especially for babies under 3 months old and the elderly.

The CDC recommends that children receive their first DTaP (diphtheria-tetanus-acellular pertussis) vaccine at 2 months old, followed by boosters at 4 months, 6 months and 15 months.

"Ask your pediatrician about the CDC childhood immunization schedule."

This study, led by Jason Glanz, PhD, of the Institute for Health Research at Kaiser Permanente Colorado in Denver, looked at whether pertussis rates appeared to be influenced by undervaccination in children aged 3 and younger.

Undervaccination means that children may have received one or more of the pertussis vaccination shots, but they did not receive the full series of four shots recommended by the CDC.

The researchers used data from 2004 through 2010 for eight managed care organizations participating in the Vaccine Safety Datalink program.

The researchers compared the vaccination status of all the children they found with laboratory-confirmed pertussis to that of children without pertussis.

For every child with pertussis, the researchers matched that patient to four comparison patients by age, sex, managed care organization location and date seen at their clinic.

The degree of undervaccination of the children was based on how many doses they were missing for their age.

A total of 72 children with pertussis were matched to a total of 288 control comparison children.

Among the 72 children with pertussis, 17 percent (12 children) were hospitalized and 47 percent (34 children) had been undervaccinated for the DTaP.

Meanwhile, among the 288 comparison children without pertussis, 22 percent (64 children) had been undervaccinated for the DTaP.

The researchers therefore determined that children who were undervaccinated were much more likely to contract pertussis.

Children who missed three doses (receiving only the first dose) were 18.5 times more likely to catch pertussis than those who were fully vaccinated.

Children who did not receive any of the four doses of DTaP were 28 times more likely to catch pertussis that those who received all four shots.

This study was published September 9 in the journal JAMA Pediatrics.

The research was funded through a subcontract with America's Health Insurance Plans from the US Centers for Disease Control and Prevention (CDC). The authors declared no conflicts of interest.

Review Date: 
September 8, 2013
Last Updated:
September 10, 2013