The Link Between Genital Herpes Simplex Virus-2 and Bacterial Vaginosis 

What is Bacterial Vaginosis (BV)?

Bacterial vaginosis (BV) is one of the most common causes of abnormal vaginal discharge seen in females who are sexually active. Generally, one notices unpleasant symptoms, such as vaginal odor, itching, watery discharge or pain. At least half to 2/3 of ladies with BV may not be aware of their conditions as they can have no symptoms at all.

BV is a condition due to overgrowth of pathogenic bacteria Gardnerella vaginalis and other anaerobic bacteria following the loss of good vaginal lactobacilli.

Aside from affecting a female’s quality of life, BV is known to increase risk of STDs, and can affect a person’s reproductive ability-causing spontaneous abortion, premature delivery, and more.

Although BV is not classified as an STD, it is associated with sexual activities and seen in women with higher frequency of sexual intercourse or those with more numbers of sexual partners. Other risk factors for BV include:

• douching
• new sexual partners
• not using barrier contraception 
• having other concurrent untreated STDs

What is Herpes Simplex Virus Type-2 (HSV-2)?

Herpes Simplex Virus (HSV) is a common STD seen globally. HSV type 2 is one of the most common causes of sexually related genital ulcers. While one can present HSV-2 with genital blisters, pain, itch and ulcers, one can also be asymptomatic yet shedding the virus continuously. In fact, more than 80% of people with HSV-2 are asymptomatic shedders of the virus.

In this article, we explore the association between these 2 conditions — BV and genital HSV-2. The article is written in hopes of increasing awareness for both conditions, and encouraging readers to consider getting screened and treated for both conditions. 

Although both conditions do not pose an immediate health threat, they can have long term health implications if left alone and untreated. 

What is the association between BV and genital HSV-2?

The relationship between BV and HSV-2 is a unique one. Those with BV are more likely to contract HSV-2 from their partners than someone without BV. Those with HSV-2 infections have a higher risk of acquiring BV compared to people without HSV-2 infections.

Effect of healthy vaginal lactobacillus against HSV-2 virus replication

By nature, the vagina is a sterile microenvironment on its own, housing millions of healthy lactobacillus, self-sustaining in flushing out bad bacteria/ particles and generating good bacteria to maintain the internal pH ecosystem. The actual mechanism of how the lactobacillus in the healthy vagina protects HSV-2 infection remains much to be discovered.

There are studies that suggest the presence of good lactobacillus such as lactobacillus salivarius, Lactobacillus plantarum or Lactobacillus brevis in cell cultures reduce HSV-2 viral replication up to more than 90% and reduce acquisition of HSV-2 infection, suggesting the protective role of these good lactobacillus. 

Untreated BV Increases risk of contracting genital HSV-2 infection

In bacterial vaginosis, there is an alteration of the vaginal flora with depletion of the good lactobacillus, and an overgrowth of anaerobic bacteria, including Gardnerella vaginalis bacteria. 

Such hostile vaginal microenvironments, without the protective effect from good lactobacillus, will increase the risk of contracting STDs, including HSV-2 infections. Additionally, the occurrence of bacterial vaginosis is associated with women with a greater number of sex partner(s) and higher frequency of sexual intercourse. These can also be independent risk factors of encountering STDs including HSV-2 infection.

Genital HSV-2 infection can increase risk of BV

It is postulated that genital HSV-2 infection or even asymptomatic constant HSV-2 viral shredding, can lead to activation of the immune system in the vaginal mucosal. This, in addition to natural occurrences, such as female hormonal fluctuations and normal changes in the vaginal microbiome, can lead to an increased occurrence of BV. 

The other possible explanation is due to the thriving Gardnerella vaginalis bacteria on iron. This is based on the understanding that BV tends to occur more commonly peri-menstrual (before and after) timing due to availability of iron. In genital HSV-2 infection/ persistent viral shedding, this can create a microenvironment with iron allowing the overgrowth of Gardnerella vaginalis bacteria.

The never-ending vicious cycle of BV-genital HSV-2

Interestingly, in a vicious cycle, with the increased risk of BV, the person with genital HSV-2 can transmit/ infect HSV-2 virus even more as untreated BV can increase further viral shedding of HSV-2.

The STD implications of vicious cycle of BV-genital HSV-2

There are increasing clinical studies showing that both genital HSV-2 infections and BV increase the risk of acquiring Human Immunodeficiency Virus (HIV) and transmitting HIV. Hence, it is worth considering screening for HIV in one who has HSV-2 and BV.

Further vicious cycle of HIV-genital HSV-2-BV

In a HIV positive person, due to a persistently compromised immune system, one is predisposed to contracting genital HSV-2 has a higher risk of genital HSV-2 flare ups (tends to be more severe), a higher risk of genital HSV-2 reactivation, and in a negative vicious way, increases susceptibility to developing BV and further HSV-2 viral shedding — the cycle never ends. 

What should we do if we have genital HSV-2? Or BV?

If one is concerned of contracting genital HSV-2 infection or BV infection, please do not hesitate to reach out to your doctor.

While history and physical examination can facilitate the right diagnosis, HSV-2 viral infection can be picked up with herpes simplex virus PCR test or herpes simplex virus antibody blood tests. In the case of BV, vaginal swab can be beneficial in nailing down the diagnosis and future treatment. Your doctor will need to understand your health condition and concerns before being able to guide you on the tests to proceed with. 

If there is concern of exposure to HIV or other STDs, it is worthwhile to consider a screening test, as having one STD may heighten your chances of contracting a second, third or fourth. 

STDs commonly can be asymptomatic and left untreated can cause health complications, as well as unknown social implications to our loved ones.

How is genital HSV-2 infection or BV treated?

Genital HSV-2 infection is managed with antiviral medication (such as Acyclovir, Valocyclovir, Fanciclovir). However, as genital HSV-2 infection is associated with invariable recurring viral shedding, recurring flare up of genital HSV-2 is common. Hence, some patients may opt for a longer term of suppressive antiviral medication to reduce flare ups, viral shredding and risk of infecting their sexual partner(s).

BV can be treated with antibiotics in the form of oral tablets or vaginal pessaries. As one of the main causes of depletion of healthy vaginal lactobacillus, probiotics play a beneficial role in reducing the recurrence of BV. 

Every patient can have different clinical presentations, concerns, and lifestyles. It is always important to consult your trusted physician to come up with an individual realistic treatment plan to manage both conditions above.

Some questions to ponder over the relationship of genital HSV-2 and BV

• Can suppressive antiviral treatment for HSV-2 reduce the risk of BV?
• Can BV treatment (short-term or long term) also reduce the risk of genital HSV-2 flare ups?

Currently, there are ongoing clinical research studies for the questions above, with potential results. Having said that, as we now know the  nature of both genital HSV-2 and BV infections, it is worth managing both genital HSV-2 infection and BV concurrently.

References:

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3. Johnston C, Magaret A, Yuhas K, et alP2.11 Association between genital herpes simpex virus type-2 shedding and presence of bacterial vaginosis-associated bacteria. Sexually Transmitted Infections 2017;93:A74-A75.
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