Table 5. Multivariate analysis of the effectiveness of pertussis vaccination and chemoprophylaxis of household contacts in reducing household transmission, Catalonia and Navarre, Spain, 2012–13.

Characteristic of household contact	Adjusted odds ratioa	95% CI	p value
Vaccination statusb (≤ 18 years)
Fully vaccinated	0.350	0.138 to 0.884	0.026
Undervaccinated	0.403	0.152 to 1.068	0.067
Unvaccinated	Reference		–
Received chemoprophylaxisc
Yes	0.379	0.241 to 0.597	0.001
No	Reference		–

CI: confidence interval.

^a Adjusted by age of contacts, sex of contacts, relationship with primary case, sex of primary case, age of primary case and pertussis vaccination status of primary case.

^b Vaccination status was categorised as fully vaccinated (≥ 4 doses of vaccine), undervaccinated (< 4 doses) or unvaccinated (no dose).

^C Azithromycin was used.