How BV Affects HPV Risk and Cervical Health

BV and beyond: What is my risk of HPV infection with persistent BV?

Cervical cancer is one of the most preventable cancers in modern medicine. It is estimated of globally 600,000 new cases of cervical cancer by the World Health Organization in 2020. Persistent HPV infection is a known main cause of development of cervical cancer. While HPV vaccination significantly reduces HPV infection, thereafter risk of cervical cancer, the vaccine uptake remains slow. Able to identify and modify concurrent risk factors of persistent HPV infection can reduce risk of cervical cancer.

A common vaginal infection known as bacterial vaginosis (BV) can affect up to 30% of women. Although BV is generally a female-related vaginal infection and result from the imbalance of the vaginal microflora, it can play a pivotal role in prevention, or clearance of HPV infection.

In this article, we want to explore the relationship of BV and HPV infection- in both women and men. We strive to understanding the association between the two conditions, encourage medical management of these two pathogenic conditions to minimize the risk factors of developing cervical cancer.

Women: Cervico-vaginal micro-environment and innate immunity

The cervix and the vaginal mucous lining have their own microflora and defense immunity, serving as a main physical barrier against external insults and pathogens. A healthy woman in reproductive age’s cervico-vaginal lining is covered predominantly with Lactobacillus spp. Lactobacilus spp has antibacterial properties, producing chemicals such as hydrogen peroxide, chemo-proteins, an acidic genital pH and create an environment that is unsuitable for bad bacteria or pathogens to thrive.

An intact cervico-vaginal microbiome can act as a physical barrier against STDs including HPV infections, and facilitate with clearance of HPV if contracted.

Women: Cervico-vaginal environment dysbiosis

Women with BV have higher risk of developing cervical HPV infection in comparison to women without BV.

The actual mechanism of BV affecting cervical HPV infection remains unknown, though there are some postulated hypothesis:

BV potentially creates an inflammatory state in the cervico-vaginal microenvironment following the decrease of Lactobacillus spp.
Following alternation of the cervico-vaginal microenvironment in BV, by products such as ammonia, sialidase etc can cause oxidative stress and break down the cervical mucus and increase susceptibility of HPV insult.
With a poor cervical lining integrity and protective barrier, HPV infection can easily adhere, invade and incorporate its viruses onto the cervical cells and the surrounding reproductive organ.

All in all, BV predisposes one towards HPV infection and delays clearance of the virus, potentially result in persistent HPV infection and eventually progress to precancerous and cancer of the cervix.

What are the common risk factors of BV and HPV infection?

Risk factors of developing both conditions include:

early onset (age) of being sexually active
history of multiple sexual partner(s)
history or current untreated STDs
not using barrier contraception (condom)

What can we do with the facts on BV and HPV above?

Consider screening and treating BV if you are sexually active- definitely if you are symptomatic, if you are asymptomatic/unaware of your symptoms you should consider screening regularly as well.
Do get treated if you are found to have BV.
Consider physical barrier contraception (condom).
Limit number of sexual partner(s).
Consider HPV vaccination if you are age-eligible and has yet to do the vaccine.
Consider regular pap smear and HPV testing (for female).
Do treat if you are having HPV infection.

References:

Martins BCT, Guimarães RA, Alves RRF, Saddi VA. Bacterial vaginosis and cervical human papillomavirus infection in young and adult women: a systematic review and meta-analysis. Rev Saude Publica. 2023 Jan 6;56:113.
Qi, J., Dai, C., Song, L. et al. Association between bacterial vaginosis with human papillomavirus in the United States (NHANES 2003–2004). BMC Women's Health 24, 138 (2024).
Onywera H, Williamson AL, Ponomarenko J, Meiring TL. The Penile Microbiota in Uncircumcised and Circumcised Men: Relationships With HIV and Human Papillomavirus Infections and Cervicovaginal Microbiota. Front Med (Lausanne). 2020 Jul 30;7:383.
Bagnall P, Rizzolo D. Bacterial vaginosis: a practical review. JAAPA. 2017;30(12):15–21.
Singh D, et al. Global estimates of incidence and mortality of cervical cancer in 2020: a baseline analysis of the WHO Global Cervical Cancer Elimination Initiative. Lancet Glob Health. 2023.