California Gonorrhea Surveillance System: Sample-Based Collection of Surveillance Data

Background:
Following years of decline, California has seen recent increases in gonorrhea in all demographic groups. Case-based surveillance provides insufficient data to fully understand these increases or to design effective interventions.

Objective:
To improve existing surveillance through collection of demographic, healthcare, and risk factor data that can lead to programmatic action.

Method:
The California Gonorrhea Surveillance System (CGSS) is a statewide system that incorporates a random 10 percent sample of reported gonorrhea cases, plus over-sampling 100 percent in selected local health jurisdictions (LHJs). Pre-populated interview records are transmitted to LHJs. Demographic and risk history information are gathered through case interview by disease investigative staff. Clinical data are collected from the provider. For analysis, data are weighted to reflect sampling frames and response rates. Quality control is conducted regularly, and feedback is provided to staff.

Result:
From January 1, 2007 through June 30, 2007, the total number of reported GC cases was 16,107. Among 2489 sampled and eligible cases, 1544 were interviewed; the response rate was 62.0 percent.
Eighty-three percent of males and 44% of females were symptomatic. Gender of sex partners (GSP) of those interviewed was: 22.6% men who have sex with men (MSM), 29.2% heterosexual male, 48.2% female. Percent of MSM who reported HIV co-infection was 25.3%, compared with 0.5% of heterosexual men and no women.
Proportions of methamphetamine use were similar across GSP (11% to 15%). Incarceration was significantly lower among MSM (6%), compared to heterosexual men (23%), and women (15%). MSM reported significantly higher Internet use to find sex partners than heterosexual men (31% versus 6%).

Conclusion:
The California STD Control Branch has responded to increases in gonorrhea with a case report surveillance system to be used for actionable, public health control strategies.

Implications:
Sample-based surveillance is feasible and operational. Additional research is needed to determine if risk factors are causal.