To the Editor: The recent report on the evaluation of different strategies for partner notification (PN) for syphilis1 and the accompanying editorial2 provided interesting information regarding this time-honored sexually transmitted diseases (STD) program activity. However, we think that there are additional PN issues to be considered as STD program managers struggle to efficiently deliver effective intervention services for all STDs at a time when resources for field investigations are diminishing. Considering the declining national incidence of syphilis and the opportunity in many communities to eliminate syphilis, we think it is time to shift the emphasis of syphilis PN to the transmission or "front end" of the problem. By that we mean that more effort should be placed on the prompt identification and treatment of infectious syphilis cases (primary and secondary stage) and their partners. Surveillance efforts can be enhanced for symptomatic infections and program objective time periods for interviewing, reinterviewing, and partner treatment can be shortened. In July 1997 in San Diego County, CA (population 2.7 million; 1996 infectious syphilis incidence of 1.7 per 100,000 population), the program objective time periods were all shortened by about 50% (details available from author). Persons identified as associates (persons in case's sexual network but not sex partners-called "clusters") are treated preventively (formerly, only infected associates were treated). Also, two or more investigators are sometimes assigned to a case to meet program objectives. To compensate for this additional "front end" work, investigator PN activities were modified to decrease the amount of field work for asymptomatic syphilis cases. Early latent syphilis cases that have a convincing history of acquiring infection within the past 6 months receive investigator-assisted PN for infectious syphilis as described; however, no associate interviews are conducted. For other early latent cases, investigator-assisted PN is provided only for the current or steady partner or for a known pregnant partner, and the patient is asked to notify other partners and/or a letter is sent (fulfills duty to warn for personal health). In addition, for all early syphilis cases the time period for eliciting the names of exposed sex partners was shortened-45 days for primary, 90 days for secondary, and 180 days for early latent syphilis cases. Our change in approach for early latent syphilis was based on a review of data for 1994 to 1995 in San Diego County. Since 1990, infectious syphilis had declined more than 75% to an annual mean of 76 cases per year in 1994 to 1995 (mean annual incidence 2.9 per 100,000 population). During 1994 to 1995, there were 156 early latent syphilis cases identified. Table 1 shows that field investigations identified only 9 untreated infectious syphilis cases. Of the 8 cases among sex partners, 7 were the current or steady partner, usually the easiest partners to locate and treat. In addition, there were 109 female partners of early latent cases identified, 11 of whom were pregnant. Of these, 10 (91%) had already been identified and treated by their own physician. We estimated that, on average, 3.5 hours were required for each of the 866 field record documented investigations. This equates to 1.5 investigator full-time equivalents (investigator total salary/benefits cost $22.50/hr) at a cost of approximately $7,020 per infectious case/untreated pregnant female identified. Applying our currently early syphilis investigation approach to 1994 to 1995 cases, we would have missed only 1 sex partner with infectious syphilis and 1 untreated infected pregnant woman during those 2 years.TABLE 1: Infectious Syphilis Cases Identified Among Sex Partners and Associates of Early Latent Syphilis Cases (N = 156) Through Field Investigation, San Diego County, CA, 1994–1995It is often argued that the preventive treatment of sex partners who may be incubating infection (with a negative serological test) plays an important role in preventing transmission. However, as Peterman1 and others3 have pointed out, there is no practical way to quantify this effect. Considering the incubation period of syphilis and the usually prompt investigation of infectious cases, the potential for treating partners of infectious cases who are incubating syphilis before they become infected/infectious is great, and the impact on overall transmission is probably substantial. In contrast, the likelihood of partners of an early latent syphilis case being in the incubation phase is probably low because most potential transmission exposures occur at a time period in the past that is much greater than the usual incubation period of primary syphilis. Therefore, little can be gained from preventively treating such partners, especially in communities with a low syphilis incidence. The current epidemiology of syphilis is telling us that PN and other syphilis control activities need to be modified to realize the most impact on transmission for the effort expended. Continuing PN services as has been done for years, or to perform PN even more thoroughly, will no doubt prove to be inefficient in most settings and will not be the most effective overall use of limited STD resources.
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Gunn et al. (1998) studied this question.