ESTIMATING THE BURDEN OF PERTUSSIS IN
OLDER CHILDREN AND ADOLESCENTS
Cagney
M1, MacIntyre CR1, McIntyre P1, Torvaldsen
S1, Melot V2
1National
Centre for Immunisation Research and Surveillance of Vaccine Preventable
Diseases, The Children's Hospital at Westmead, Westmead Australia and 2GlaxoSmithKline
Australia, Dandenong Australia
Adolescent
and adult pertussis has become increasingly recognised as a cause of
morbidity. Pertussis is undernotified in older children, so the burden of
disease is poorly enumerated.
Objective: To describe the burden
of pertussis in children aged 5-14 years.
Methods: A community-based telephone interview of parents of
2,020 children aged 5-14 years in Western Sydney. Anti-PT and FHA IgG antibody ELISA technique was performed
on 149 children. The Centres for Diseases control (CDC) clinical case
definition for pertussis was used for the analysis of symptoms.
Results: 14% (281/2020) of children
met the CDC definition for pertussis.
Children aged 5-9 years were more likely (p<0.001) to meet the
case definition (16%, 190/1167) compared to children aged 10-14 years (11%,
91/856). Exposure to a
pertussis case was higher in 10-14 year olds with a cough of 2 weeks or
more (4.4%, 7/160) compared to
5-9 year olds (0.4%, 1/280, P<0.01). Of children meeting the CDC definition for pertussis who
saw a doctor, whooping cough was diagnosed in only 1% (3/261). Serology
showed increased susceptibility to pertussis in older children.
Conclusion: The higher prevalence of cough symptoms in younger
children probably reflects the generally higher prevalence all-cause
respiratory infections in this age group. High risk of pertussis in older children is reflected in
the much higher rate of known pertussis exposure in the age group 10-14
years. Pertussis is
significantly under-diagnosed in older children, who remain an important
reservoir for infection. A booster dose of vaccine should be considered in
this age group.