Vaginal dysbiosis and HPV: restoring balance to help prevent cervical cancer?

The vaginal microbiota is receiving growing attention because of its implications for women’s health.
In January 2026, a Mexican research team ¹published, a review of the vaginal microbiota and its role in various conditions, particularly cervical cancer and the risk of HPV-associated cervical lesions. 

Protected by lactobacilli

The vaginal microbiota is marked by low diversity. It is generally dominated by lactobacilli, especially L. crispatus, L. jensenii, L. gasseri and L. iners. These lactobacilli help maintain vaginal health, protect against pathogens and regulate inflammation, for example by competing for nutrients, producing bacteriocins, modulating the immune system and reducing vaginal pH. 

Conversely, high microbial diversity is associated with an increased risk of sexually transmitted infections, pelvic inflammatory disease, pregnancy complications (infertility, premature birth, low birth weight) and infection with human papillomavirus (HPV),increasing the risk of progression to an HPV-related cervical lesion.

Vaginal microbiota and HPV

In the specific case of HPV, vaginal dysbiosis promotes viral progression by creating a pro-inflammatory environment.
The reduction in lactobacilli and the proliferation of anaerobic bacteria (Gardnerella, Sneathia, Atopobium) inhibit apoptosis, increase inflammatory cytokines and raise pH. These changes all make it easier for HPV to become established in the cervix and adjacent uterine tissue. 

Conversely, a microbiota rich in lactobacilli is associated with a less inflammatory microenvironment. According to some studies, it may modulate the expression of the viral oncoproteins E6/E7 in infected cells. This context is associated also with more favorable HPV clearance and may help limit progression to cervical lesions. 

In addition, excision of precancerous cervical lesions induces a change in the composition of the vaginal microbiota only in women who clear HPV, with a shift from pathogenic bacteria (Prevotella, Sneathia) to protective lactobacilli (L. iners then L. crispatus). By contrast, in cases of persistent HPV, no change appears. 
 

Finally, probiotics, namely Lactobacillus strains (L. crispatus, L. reuteri, L. casei and/or L. rhamnosus) administered orally or intravaginally, appear to improve HPV clearance and reduce cervical lesions.
Results remain mixed, with effects that vary by strain, duration and population, but some probiotics could still complement treatment and prevention strategies.

Differences from one population to another

The composition of the vaginal microbiota varies across populations, and according to geographic origin, pregnancy, the menstrual cycle and age.
The dominant Lactobacillus species thus differ among Canadian, Chinese, Indian and Mexican women.
In cases of HPV, progression to cervical lesions and then cancer is associated with changes in the microbiota: among Mexican women, L. crispatus and L. iners predominate in women without disease, while Sneathia spp. appears in lesions and Fusobacterium in cervical cancer.

According to the authors, current research points to the need for additional studies, such as exploring how cervical cancer cultures respond to different Lactobacillus species.
The aim is to improve therapeutic treatment approaches and reverse dysbiosis to support recovery and even prevent these cervical cancers.