An experimental HIV vaccine failed a key trial in South Africa
The vaccine did not reduce the risk of being infected with the virus that causes AIDS
![HIV virus particles](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2020/02/020320_ac_hiv_feat.jpg?fit=1028%2C579&ssl=1)
Participants in a clinical trial testing an experimental vaccine against the human immunodeficiency virus, shown in blue, did not see a reduced risk of infection compared with those on placebo.
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