OBJECTIVE:
estimate the likelihood of pertussis according to number of vaccine doses received and age.
METHODS:
Case-control study using 2007-2011 SINAN data. "Cases" were considered to be confirmed reported pertussis cases. "Controls" were the discarded cases.
RESULTS:
5,389 cases and 10,689 controls were included. In those aged 7-12 months, cases were twice as likely [OR:2.1 (95%CI:1.3-3.4)] when only 1 instead of 3 doses had been administered. In 1-3 year-olds, likelihood was greater in those not having boosters (1 booster expected) [OR 1 dose: 2.4 (95%CI:1.6-3.8); OR 2 doses: 3.6 (95%CI:2.2-6.1); OR 3 doses: 1.6 (95%CI:1.3-2.2); OR 0 dose: 2.8 (95%CI:1.7-4.8)]. In 7-15 year-olds, cases were 60% more likely in those having had 1 booster instead of 2 [OR:1.6 (95%CI:1.2-2.3)].
CONCLUSION:
incomplete immunization increases likelihood of contracting pertussis in all age groups studied, mainly 7-15 years.
Pertussis Vaccine; Whooping Cough; Immunization Schedule; Disease Notification; Case-Control Studies
