Pertussis infection is associated with significant morbidity in younger chi
ldren (<4 years), which can include pneumonia, seizures and encephalopathy.
Around one in 250 cases of pertussis in infants under the age of 6 months
lead to death or severe brain damage. In the United Kingdom the control of
pertussis infection has been based on a three-dose schedule of combined dip
htheria, tetanus, whole-cell pertussis vaccine (DTPw) during the first 4 mo
nths of life. Coverage rates for primary vaccination are currently at high
levels of over 90 per cent and infection rates are relatively low (approxim
ately 1.2 per 100000). However, there are concerns over the potential under
-reporting of pertussis and clear shifts in the age pattern of notified cas
es are evident, with surveillance data suggesting a possible upward trend i
n the absolute numbers of infections in those at most risk (i.e. infants <3
months old). The addition of childhood booster dose(s) of pertussis vaccin
e to the standard schedule has potential clinical benefits and may be cost-
effective. Selective adult booster immunization may also have a role to pla
y in controlling the circulation of pertussis.