With no known cure or vaccine, the HIV (human immunodeficiency virus) infection can be considered a long-running pandemic that has persisted for decades. In the absence of a permanent solution, preventive measures are the only viable strategy. However, a new study states that certain vaginal bacteria can affect the effectiveness of a class of drugs used to prevent the contraction of the infection.
According to the study, accumulation of additional genera of bacteria microbiome in the vagina can lead to the imbalance of the ecosystem or Dysbiosis, which in turn can affect the efficacy of pre-exposure prophylactic (PrEP) drugs, that are required for the prevention of the infection's transmission.
"These studies demonstrate how dysbiotic vaginal microbiota may impact PrEP drugs and provides evidence linking vaginal bacteria to PrEP efficacy in women," wrote the authors in the paper, which was published in the journal PLOS Pathogens.
An Infection With No Cure
HIV is two species of retroviruses that attack and infect cells that are associated with the immune system and protect the body from infections. With time, it can lead to acquired immunodeficiency syndrome (AIDS), where the immune system becomes weak and incapable of defending the body. This leaves the body vulnerable to other diseases and infections. After contraction, the infection can be treated using antiretroviral drugs, and the symptoms can be controlled. Nevertheless, once infected, an individual will have to live with it rest of the life.
According to the WHO (World Health Organization), as of 2019, approximately 38 million people are living with HIV/AIDS worldwide, and nearly 690,000 people died of HIV-related causes in 2019 alone. So far, about 33 million people in total have died of the infection. It can infect people of any age and is transmitted through contact with body fluids of an infected person, through sexual contact, or through other routes such as from mother to fetus and blood transfusion.
In the absence of a cure, strategies such as PrEPs, a course of antiviral drugs prescribed to potential HIV-individuals, are ineffective. These drugs have been found to be highly effective in preventing the contraction of HIV in men. However, in women, they are less effective. Latest evidence has suggested that the vaginal microbiome is linked to an increased risk of HIV infection and inefficiency of PrEPs in women.
Vaginal Bacteria and Drug Effectiveness
For the study, the authors examined the manner in which vaginal bacteria altered the levels of PrEP drug and the effect on the rates of HIV infections. They used samples of cervicovaginal lavage from women who had bacterial vaginosis (BV), and also women who did not. BV is a common vaginal infection that leads to an imbalance of vaginal bacteria. It can cause discomfort, discharge, and itching. It is also associated with the incidence of sexually transmitted infections and negative gynecological outcomes in women. Existing treatments for BV often fail and its recurrence is fairly common.
The researchers discovered that bacteria linked to BV—except healthy Lactobacillus bacteria—were capable of metabolizing PrEP drugs, which could potentially decrease the effectiveness of PrEP. This was due to the diminished levels of the drug's availability. Therefore, the authors stated that improved interventions to tackle BV will play a crucial role in bettering the efficiency of HIV prevention measures in women.
Dr. Nichole Klatt, lead author of the study concluded, "Women's health, and factors that contribute to health and disease prevention in women are grossly understudied. This study demonstrates the critical need to develop better treatments for bacterial vaginosis, and in general, to promote more studies of women's health."
