Several long-acting injectable suspensions with small-molecule antiviral drugs as active ingredients have recently been launched for PrEP for human immunodeficiency virus (HIV). These suspensions exhibit a sustained-release profile despite being small molecules, enabling infrequent administration, such as once every 1 or 2 months. Based on the track record of these suspensions for HIV, we hypothesized that long-acting injectables using a small-molecule active pharmaceutical ingredient may also meet the unmet medical needs for COVID-19 PrEP.