Results from HIV incidence study in Swaziland

The results from a nationally representative HIV incidence study in Swaziland indicate that the national rate of new HIV infections is 2.38% among adults ages 18-49. This figure, comparable to the 2009 UNAIDS estimate of 2.66% for Swaziland adults ages 15-49, suggests that the HIV epidemic in Swaziland may have begun to stabilize in the past few years. The findings of the Swaziland HIV Incidence Measurement Survey (SHIMS) were presented today at the XIX International AIDS Conference in Washington DC.

"The country continues to have very high HIV incidence rates. Since HIV services in Swaziland are more widely available now and we understand that ART treatment prevents the spread of new infections, the Ministry of Health will use these new results to plan HIV prevention, care, and treatment programs in Swaziland," said Rejoice Nkambule, deputy director of health services - public health at the Ministry of Health. SHIMS was led by the Swaziland Ministry of Health and supported by the U.S. Centers for Disease Control and Prevention (CDC) and ICAP at Columbia University through the U.S. President's Emergency Plan for AIDS Relief (PEPFAR).

SHIMS is a multi-phase study designed to evaluate the impact of HIV prevention and treatment services in the country. The first phase of the SHIMS survey included approximately 13,000 households in Swaziland, representing a cross-section of the national population and consisting of 18,154 men and women, ages 18-49. Findings from the first phase indicated that the national prevalence of HIV in Swaziland is the highest in the world, with 31% of adults infected.

HIV-negative adults from the survey who gave permission were retested six months later and the number of new HIV infections were assessed using state-of-the-art laboratory methods. Retention rates were high, with 94% of participants completing follow-up at six months. "This is the gold standard method for measuring HIV incidence and it hasn't been attempted before at a national level," said Jessica Justman, MD, ICAP's senior technical director, and Associate Professor of Clinical Epidemiology at Columbia University's Mailman School of Public Health. While overall HIV incidence is 2.4 %, HIV incidence among women in Swaziland peaks among those 20-24 and 35-39 years old, with rates of 4.2 % and 4.1 %. Among men, HIV incidence peaks among those 30-34 years old, at 3.0 %. Not knowing the HIV status of the current partner predicts new HIV infection for both men and women and suggests prevention and treatment programs need to target this specific problem.

"SHIMS provides a remarkable epidemiologic look into the most severe national HIV epidemic in the world. Clearly, the strategic scale-up of effective HIV interventions in combination is warranted. SHIMS has established an unequivocal baseline incidence rate against which to judge the effectiveness of such strategies for an entire national population. This may not be feasible anywhere else," said Dr. Jason Reed of the CDC.

While SHIMS is primarily assessing new HIV infections, the study has several other goals such as enhancing laboratory infrastructure and strengthening research capacity in Swaziland.