Table 3.

Symptom clusters and recent Bordetella pertussis infection in adults and children

Adult

Presence of exercise intolerance, wheezing and vomiting, or exercise intolerance and wheezing but without headache or muscle

		*Recent Bordetella pertussis* infection^a**

		Yes	No

Symptom complex present	Yes	8	39
	No	3	106

Sensitivity = 0.73 (95% CI = 0.43 to 0.90)

Specificity = 0.73 (95% CI = 0.65 to 0.80)

Positive predictive value = 0.17 (95% CI = 0.09 to 0.30)

Negative predictive value = 0.97 (95% CI = 0.92 to 0.99)

Child

Presence of vomiting and exercise intolerance but not wheezing or sneezing OR vomiting but not headache OR phlegm but not headache or wheeze OR phlegm and exercise intolerance but not wheeze or sneeze.

		*Recent Bordetella pertussis* infection^a**

		Yes	No

One of these four symptom complexes present	Yes	8	7
	No	4	47

Sensitivity = 0.67 (95% CI = 0.39 to 0.86)

Specificity = 0.87 (95% CI = 0.76 to 0.94)

Positive predictive value = 0.53 (95% CI = 0.30 to 0.75)

Negative predictive value = 0.92 (95% CI = 0.82 to 0.97)

↵a As defined by an oral fluid IgG antibody titre to PT titre of 70 arbitrary units or more.11