Table 2.
Sensitivity, specificity, and predictive values for the WHO case definition and the PAHO case definition for the 556 Zika and 548 non-Zika PDCS cases reported January 2016 – February 2017.a
| Case definition | Elements of the case definition | Sensitivity (95% CI) | Specificity (95% CI)b | Positive predictive value (95% CI)b | Negative predictive value (95% CI) b |
|---|---|---|---|---|---|
| WHO | Rash and/or fever AND At least 1 of the following: • Arthralgia • Arthritisc • Conjunctivitisd |
31·7% (27·9%, 35·6%) |
74·3% (70·4%, 77·8%) |
55·5% (50·0%, 60·9%) |
51·7% (48·2%, 55·2%) |
| PAHO | Rash AND At least 2 of the following: •Fever •Conjunctivitisd •Arthralgia •Myalgia •Peri-articular edema |
19·6 % (16·5%, 23·1%) |
98·2% (96·6%, 99·1%) |
91·6% (85·1%, 95·5%) |
54·6% (51·5%, 57·7%) |
Acronyms: CI, confidence interval; PAHO, Pan American Health Organization; PDCS, Pediatric Dengue Cohort Study; WHO, World Health Organization
An expanded version of this table, with the raw data and additional diagnostic indices, is provided in Table S2.
During the Zika outbreak that occurred during the study period, January 2016-February 2017, there were uncharacteristically few cases of dengue in the study population. Thus, the specificity and predictive values are higher than they would be if the non-Zika cases included typical levels of dengue and/or chikungunya.
Arthritis is not a recorded variable for medical assessments of our pediatric population. Instead, doctors record proximal and distal arthralgias. The estimated indices are lower for the WHO case definition than they would be if arthritis was a recorded variable.
The four indices of interest are calculated with conjunctival involvement (conjunctivitis and/or conjunctival injection). The estimated indices are slightly higher than if they were estimated using conjunctivitis alone.