Researchers put an early end to the trial for a potential HIV vaccine

Researchers have temporarily called off the remainder of a long-term study after preliminary results indicated that the proposed HIV vaccine Truvada was ineffective in preventing the spread of the disease to women, according to a recent article published by ABC News.

Scientists told the news provider that early findings showed that the drug had no protective effect on African women at high risk for contracting HIV. Previous research had indicated that gay men who adhered to their prescribed Truvada regimens were 73 percent less likely to become infected with the virus than those who were not vaccinated.

"We were surprised by the outcome [of the female study]. We were advised that there was no benefit to continue for the next several months," researcher Timothy Mastro told the news source.

According to the Centers for Disease Control and Prevention, more than 1.1 million Americans are living with HIV, although an estimated 21 percent of these cases are undiagnosed. The organization notes that gay men account for more than half of the new infections reported annually in the U.S., and African-American men and women are more than seven times more likely to contract HIV than whites.