Citizen Scientists Help Map the Healthy Vaginal Microbiome

About a decade ago, when microbiologist Sarah Lebeer set up her lab at the University of Antwerp, she chose to focus on an aspect of the microbiome that was surprisingly understudied.

“We don’t understand what is a healthy microbiome. [While starting my work], I thought, ‘We actually need better reference data’,” recalled Lebeer. “And that was especially the case for the vaginal microbiome.”

The vaginal microbiome plays a crucial role in fertility, pregnancy, and preventing vaginal diseases.¹ As such, scientists have studied it in the context of different diseases. Indeed, while Lebeer had previously studied the vaginal microbiome from patient samples collected by clinicians, this data did not represent healthy women.

To bridge this gap, Lebeer set up a citizen science project wherein thousands of healthy women from Belgium self-sampled their vaginal microbiomes and mailed the specimens to the researchers for further testing. Results from the project—called Isala, after the first female Belgian doctor Isala Van Diest—provided a reference map of the healthy vaginal microbiome, which can also help scientists better understand the microbiome’s role in disease.²

Inviting People to Swab Their Vaginal Microbiomes

When Lebeer started the work about six years ago, her colleagues warned her that the journey would not be simple because of societal taboos surrounding vaginal samples. With that in mind, Lebeer hoped to recruit at least 200 people. But things soon snowballed.

“We sent out the call [for participants], and within an hour, we had 200 volunteers. Within a day, we had 1,000 or 2,000; within a few days, we had 6,000 volunteers, and we had to stop registrations,” recalled Lebeer. “I was not prepared for this enthusiasm.”

Lebeer and her team mailed self-sampling kits to about 4,000 women—between the ages of 18 and 98—who answered a detailed questionnaire about their health and habits. To ensure that the participants felt valued, Lebeer designed the kits to look like gift boxes. Aside from the swabs, each box carried detailed instructions for sample collection.

What Does a Healthy Vaginal Microbiome Look Like?

After the participants mailed their swabs to Lebeer’s lab, the researchers isolated DNA from the samples and sequenced it. This revealed that bacteria belonging to the genus Lactobacillus occurred frequently in healthy vaginal samples, consistent with previous reports.³ Their analyses also revealed that diet, age, and menstrual cycle phases influenced the vaginal microbiome composition.

“We also saw a bit of an unexpected association with the use of menstrual hygiene products,” said Lebeer. While the microbiome of those who used menstrual cups was more abundant in Lactobacillus crispatus, which is associated with a healthy microbiome, menstrual pad users had less of this microbe.

This unexpected observation prompted the researchers to study how various menstrual products influence the vaginal microbiome. They are now recruiting participants for these studies. The scientists are also looking into how vitamin supplements or fasting can influence the vaginal microbiome. “We hope this will help women to make more informed decisions,” said Lebeer. However, she warned that the research is still in early stages and more work needs to be done.

Despite this, Isala’s launch set the ball rolling for development of the Isala Sisterhood Consortium, with scientists in several countries investigating what constitutes a healthy microbiome regionally. Early data from studies conducted in Africa hint at lower levels of Lactobacillus bacteria in healthy microbiomes, suggesting that geographical diversity may also translate into diverse vaginal microbiome compositions.⁴

Sparking other scientists’ interest in the vaginal microbiome has been one of the most exciting aspects of working on this project, said Lebeer. “We hope that others are inspired and will also research in their home country, to help women have better diagnostics and better therapeutics.”