UNAIDS estimates that 37 million people were living with HIV and 1.8 million people acquired HIV in 2017. In Africa, which has over two thirds of all people with HIV, adolescent girls and young women have the highest rates of new HIV infections. ABC (Abstinence, Be faithful, and use Condoms) prevention messages have had little impact - due to gender power imbalances, young women are often unable to successfully negotiate condom use, insist on mutual monogamy, or convince their male partners to have an HIV test.
In responding to this crisis, Salim and Quarraisha Abdool Karim started investigating new HIV prevention technologies for women about 30 years ago. After two unsuccessful decades, their perseverance paid off when they provided proof-of-concept that antiretrovirals prevent sexually acquired HIV infection in women. Their ground-breaking CAPRISA 004 trial showed that tenofovir gel prevents both HIV infection and genital herpes. The finding was ranked in the “Top 10 Scientific Breakthroughs of 2010” by the journal, Science. The finding was heralded by UNAIDS and the World Health Organization (WHO) as one of the most significant scientific breakthroughs in AIDS and provided the first evidence for what is today known as HIV pre-exposure prophylaxis (PrEP).
The Abdool Karims have also elucidated the evolving nature of the HIV epidemic in Africa, characterising the key social, behavioural and biological risk factors responsible for the disproportionately high HIV burden in young women. Their identification of the “Cycle of HIV Transmission”, where teenage girls acquire HIV from men about 10 years older on average, has shaped UNAIDS policies on HIV prevention in Africa.
CAPRISA 004 and several clinical trials of oral tenofovir led to the WHO recommending a daily tenofovir-containing pill for PrEP as a standard HIV prevention tool for all those at high risk a few years later. Several African countries are among the 68 countries across all continents that are currently making PrEP available for HIV prevention. The research undertaken in Africa by this South African couple has played a key role in shaping the local and global response to the HIV epidemic.