In the United States, the Food and Drug Administration approved Truvada for use as a pre-exposure prophylaxis (PrEP). It is not a vaccine but can be taken daily to lower the risk of infection. When PrEP was first developed and used as prescribed, it reduced the chance of HIV transmission from sex by 90 percent—more recent research puts the effectiveness at 99 percent. Some information also indicates that PrEP can reduce the risk of HIV from drugs by at least 74 percent. However, the average price of one PrEP treatment is nearly $2,000 for a thirty-day supply. The high price makes the treatment cost-prohibitive not only in the United States but also in developing countries where preventive care is most needed.