We examined trends in HIV testing rates and outcomes during 2001–2006 in a small African community with an estimated HIV prevalence of 23%.11
Testing rates increased substantially and were highest among pregnant females from 2002 onwards when antenatal testing became provider-initiated. Retesting accounted for much of the population’s testing, but growth in the proportion of seronegative first-time testers retesting leveled off as a function of time elapsed from first-time testing. HIV-positive yield of testing decreased, but nevertheless exceeded 28% in all years. Retesting yield similarly remained high with 12.6% of seronegative first-time testers diagnosed with HIV within five years of first-time testing. The median of CD4 counts at diagnosis (276 cells/mm3
for the entire study period) did not change significantly. Finally, client throughput for the two principal rate-limiting steps in the linkage-to-care process, referral for CD4 count and ART initiation, increased markedly during the study period as the availability of these services expanded.
The testing rate among adults not previously diagnosed HIV-positive increased from 4% in 2001 to 8% in 2003 and then experienced even more dramatic growth, eventually reaching 20% by 2006. This increased growth after 2003, when the ART rollout began in the community, suggests that HIV treatment availability encouraged testing. Given that ART is only now becoming widely available elsewhere in South Africa,19
the 2003 testing rate may be more indicative of current national testing rates, although this study clearly demonstrates that these rates are dynamic. These findings suggest that ongoing efforts to increase and advertise ART availability could contribute to further expansion of testing.20
The substantially higher testing rates among pregnant females demonstrate the potential effectiveness of provider-initiated testing. Pregnant females may have tested at higher rates in part because they comprise a unique group likely to receive provider-initiated test offers through antenatal care21–23
and to accept such offers out of concern for their unborn babies.24
Yet, testing rates among pregnant females were comparable to those for all other groups until 2002 when antenatal testing became routine. Thus, we expect that provider-initiated testing may effectively elevate testing rates among groups regularly accessing healthcare facilities.
Of course, provider-initiated testing will be less effective for increasing testing among groups not regularly accessing healthcare facilities. For such groups, detection of later-stage infections through TB testing will continue to contribute to a large proportion of case detection. Because we were unable to quantify either the total number of tests of TB-infected residents (the VCT data did not indicate clients’ presenting illnesses) or the numbers of residents infected with TB, we could not estimate rates of provider-initiated testing among the TB patients in this population. Nevertheless, we presume they were significantly higher than the rates of client-initiated testing among the general community population. Future research should continue to consider strategies (e.g., home-based testing25
) beyond TB testing for achieving earlier diagnoses of HIV infections among groups with irregular access to healthcare facilities.
HIV testing yield decreased as testing rates increased. This is an indication of testing program success in increasing case detection at the population level: as undiagnosed HIV prevalence falls, more tests are required for each new case identified. Nevertheless, annual yield never fell below 28% for first-time testers. Yield remained high even among antenatal care users and TB patients already receiving provider-initiated testing. These figures indicate the need for expanding testing further among the general population while continuing aggressive case detection for pregnant females and TB patients. Furthermore, the observed incidence rate of 1.9% over one year among retesters (excluding antenatal testers) highlights the importance of sustaining any expanded testing to achieve regular retesting to identify new infections.
Further evidence of the need for retesting comes from the lack of substantial change in the clinical characteristics of newly-diagnosed HIV-infected patients. Neither median CD4 counts nor distributions by WHO stage at diagnosis changed markedly. Thus, clients did not appear to be testing any earlier in the course of infection despite the rising population testing rates.
Linkage to effective HIV treatment will be necessary for seropositive clients to realize the benefits of expanded testing. The dramatic rise in referral and treatment rates observed in this study are encouraging signs of the capacity of South Africa’s healthcare sector to absorb the increased caseload that will be identified through expanded testing. Also important will be ensuring linkage of HIV-infected patients not yet eligible for treatment to social support, positive living messages, monitoring and other pre-ART care. Scaling up nutritional, educational, and psychosocial interventions for HIV-infected persons will be an important component to any effort to increase HIV testing in South Africa.
Indeed, a substantial proportion newly-diagnosed HIV-infected patients were not yet eligible for treatment upon diagnosis under current treatment guidelines.13, 14
This proportion will presumably increase further if testing expands sufficiently as HIV-infected persons are identified at earlier stages of infection. Any expanded testing program will need to be accompanied by initiatives to track these individuals, educate them regarding prevention, and provide them ongoing clinical and laboratory monitoring. As growing numbers of HIV-infected individuals not yet eligible for treatment are identified, it may also become increasingly relevant to consider revising treatment guidelines to begin ART earlier,26
though this raises further issues of treatment capacity.27
This study illuminates HIV testing rates and outcomes at the population level. Several studies in South Africa28
and elsewhere in sub-Saharan Africa19
have attempted to estimate the effects of baseline population testing through cross-sectional surveys, determining proportions of individuals who have already received HIV testing. However, these surveys sampled only small portions of the populations of interest, may have experienced substantial self-selection biases, and did not provide longitudinal data. One study estimated testing rates for Botswana’s national population by using aggregate statistics from healthcare facility reports. However, low levels of reporting and the lack of patient-specific data precluded calculation of the annual rates at which unique individuals received testing and linkage to care.29
This study has several limitations. Although we compared testing rates by age, small sample sizes for the older categories (e.g., >49) made it impossible for us to examine whether specific age groups should receive priority for HIV testing in South Africa. Moreover, the community’s small size and access to ART and other HIV-related services since 2003 may limit the generalizability of these findings to other African settings. Yet, the community’s small size made possible the measurement of population-level testing rates. Similarly, while this study’s retrospective design entailed use of incomplete data from testing registers and clinical records, it was required for analyzing the entire population, given that prospectively following every population member would have been impractical. Since each member of the study population was not followed prospectively, we also cannot account for immigration or emigration. However, the 2006 census found that only 1.0% of residents had immigrated and 0.4% planned to emigrate during that year, indicating that the population was relatively closed during the latter years of the study period.
We found a dramatic increase in population HIV testing rates over the last six years in a small South African community. Yet, in spite of these increases, testing yield remained high and patients were not diagnosed any earlier in the course of HIV disease. Thus, further expansion of testing – combined with effective programs for linking seropositive clients to care, monitoring, and treatment once eligible – remains an important public health goal. The move to provider-initiated testing increased testing rates among pregnant females in this setting. Provider-initiated testing for all non-pregnant females and males accessing healthcare facilities – as recommended by the WHO1
– coupled with careful linkage to care for seropositive clients, should be considered a critical component of the response to the HIV epidemic in South Africa.