Bacterial Vaginosis Linked to Increased STI Co-Infection, Finds National Study of 1.5 Million Women from Quest Diagnostics

Rhea-AI Summary

Quest Diagnostics (NYSE: DGX) reported results from a Health Trends study with Hologic analyzing deidentified molecular test data from over 1.5 million U.S. women (2022–2024), published in O&G Open. Overall, 38.7% tested positive for bacterial vaginosis (BV) and 28.5% for vulvovaginal candidiasis; 10.8% had both.

Among BV‑positive women, 12.0% had at least one non‑viral STI versus 3.8% of BV‑negative women. After adjustment, BV positivity was associated with higher odds of chlamydia (2.8x), gonorrhea (3.8x), trichomonas (3.6x) and Mycoplasma genitalium (1.9x). Candidiasis alone was not associated with increased STI risk. Quest noted the large, nationally representative sample as a strength, and single‑lab, limited patient data as key limitations, and highlighted its 2024 rollout of self‑collection services for BV and related infections.

Market Context

Net Selling is the platform’s recent insider-activity signal for DGX, adding a corporate-context cou...

Analysis

Net Selling is the platform’s recent insider-activity signal for DGX, adding a corporate-context counterpoint to this clinical testing study. The study’s single-laboratory limitation remains relevant when assessing generalizability and follow-through.

Key Figures

Study population: over 1.5 million women BV-positive rate: 38.7% STI co-infection rate: 12% +5 more

8 metrics

Study population over 1.5 million women United States molecular testing study, 2022-2024

BV-positive rate 38.7% women tested

STI co-infection rate 12% BV-positive women

Vulvovaginal candidiasis rate 28.5% women tested

Dual BV and candidiasis rate 10.8% women tested

STI rate among BV-negative women 3.8% comparison with BV-positive women

Chlamydia odds 2.8 times higher odds BV-positive status after adjustment

Gonorrhea odds 3.8 times higher odds BV-positive status after adjustment

Historical Context

5 past events · Latest: Jul 23 (Positive)

Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
Jul 23	Earnings report	Positive	+8.6%	Second-quarter results and raised full-year revenue and EPS guidance
Jul 10	Drug testing study	Neutral	-0.3%	Annual workforce drug-testing positivity data and substance-use trends
Jul 08	Platform integration	Positive	-2.0%	Oncology test integration expanding ordering access across community practices
Jun 24	Regulatory approval	Positive	+3.0%	New York authorization expanded Haystack MRD availability nationwide
Jun 18	Clinical study	Negative	-1.4%	Study reported multidrug resistance among community infection samples

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

DGX's recent news reactions were mixed, with positive developments producing both gains and declines.

Key Terms

bacterial vaginosis, vulvovaginal candidiasis, molecular testing, retrospective study

4 terms

bacterial vaginosis medical

"Women who test positive for bacterial vaginosis (BV) were over three times more likely"

An imbalance of the natural bacterial community in the vagina that can cause abnormal discharge, odor, and discomfort; it is not always an infection in the usual sense but a shift in which species dominate, similar to weeds overtaking a garden. Investors care because it is a common, recurring condition that drives demand for diagnostics, treatments and clinical trials, can affect regulatory reviews and labeling, and influences revenue and risk for companies developing products targeting women's reproductive health.

vulvovaginal candidiasis medical

"28.5% were positive for vulvovaginal candidiasis"

A common yeast infection of the vulva and vagina caused by overgrowth of Candida fungi that leads to itching, discharge, and discomfort; think of it as a local imbalance where normally harmless yeast grows too much. It matters to investors because its high prevalence, recurring nature, and treatment options affect pharmaceutical and medical-device markets, clinical-trial activity, regulatory approvals, and potential healthcare costs and revenue streams.

molecular testing technical

"received molecular testing from Quest between 2022 and 2024"

Molecular testing analyzes tiny biological markers—like DNA, RNA or specific proteins—to detect diseases, identify pathogens or measure treatment-related changes. Think of it as reading a biological barcode or fingerprint that tells doctors exactly what is happening at the cellular level. For investors, molecular tests matter because they drive demand for diagnostic products, influence clinical trial outcomes and regulatory decisions, and can quickly change revenue and valuation when adopted in clinical care.

retrospective study medical

"The primary limitation to this retrospective study was that the data"

A retrospective study is a type of research that looks back at existing records, medical charts, or databases to identify patterns and outcomes that already happened. For investors, these studies can provide faster, lower‑cost evidence about a treatment’s safety or effectiveness—like reading past customer reviews—but they are more prone to missing information and bias than studies that collect data going forward, so their findings are suggestive rather than definitive.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Largest nationally representative study finds 12% of patients positive for bacterial vaginosis are infected with at least one STI, such as chlamydia or gonorrhea

SECAUCUS, N.J., July 30, 2026 /PRNewswire/ -- Women who test positive for bacterial vaginosis (BV) were over three times more likely to also test positive for one or more non-viral sexually transmitted infections (STIs) than women who test negative for BV, according to a new Health Trends® study from Quest Diagnostics (NYSE: DGX) and Hologic, Inc.

In the largest national study of its kind, scientists at Quest and Hologic analyzed deidentified aggregated laboratory data from over 1.5 million women across the United States who received molecular testing from Quest between 2022 and 2024. Over one-third of women tested (38.7%) were positive for BV. Of these, 12% were co-infected with at least one STI. The findings were published in O&G Open, a peer-reviewed companion journal to Obstetrics & Gynecology, the official publication of the American College of Obstetricians and Gynecologists (ACOG).

"BV is one of the most common health problems in women, and yet research in this area of women's healthcare is sadly lacking. Our new analysis provides compelling evidence that women with BV are at significant risk for STIs based on a uniquely large dataset reflecting the nation's heterogenous population," said co-author Damian P. Alagia III, MD, a board-certified obstetrician/gynecologist and Senior Medical Director, Women's Health, Quest Diagnostics. "STIs can lead to serious reproductive and other health complications when left undetected and untreated. We hope our new data inspires much-needed additional research on this clinical area while also reinforcing for clinicians and policy makers the value of a comprehensive diagnostic approach that considers STI testing for patients with BV."

Growing evidence suggests that changes in the vaginal microbiome may contribute not only to vaginitis, a common condition associated with inflammation, discomfort and infection, but also to increased susceptibility to other STIs, including HIV, chlamydia, gonorrhea and trichomonas.

Key findings:

• Among the more than 1.5 million women tested, 38.7% were positive for BV and 28.5% were positive for vulvovaginal candidiasis. Approximately 10.8% were positive for both.
• 12.0% of BV-positive women had at least one STI, compared to only 3.8% of BV-negative women.
• After adjusting for other factors, BV-positive status was strongly associated with increased odds of having:
  • Chlamydia trachomatis: 2.8 times higher odds.
  • Neisseria gonorrhoeae: 3.8 times higher odds.
  • Trichomonas vaginalis: 3.6 times higher odds.
  • Mycoplasma genitalium: 1.9 times higher odds.
• The presence of vulvovaginal candidiasis alone was not found to be associated with an increased risk of having an STI co-infection.

Nearly 30% of women in the U.S. are believed to experience BV at some point in their life. Guidelines from the Centers for Disease Control and Prevention (CDC) recommend that women with BV should be tested for STIs, which can present with similar symptoms, complicating diagnosis. Modern molecular diagnostics can allow for comprehensive assessment of vaginal infections from a single specimen, supporting timely detection and management of infections.

"This research confirms and expands on previous research on increased STI risk in women with BV, but with the advantage of a much larger data set from which to draw conclusions," said Elizabeth M. Marlowe, MS, PhD, Executive Director, Infectious Disease, Quest Diagnostics. "This large study underscores the value of comprehensive molecular testing when clinically indicated, enabling clinicians to detect coinfections from a single specimen, optimize patient management, and strengthen evidence-based care."

The study's strengths include its large, diverse and nationally representative sample size. The detailed analysis strengthens the evidence-based literature for reliable, impactful clinical guidelines to support the use of advanced molecular testing. The primary limitation to this retrospective study was that the data was provided by a single national laboratory, and that specific patient information like additional risk factors were not available.

In 2024, Quest introduced self-collection services for bacterial vaginitis and other common genital tract infections at its more than 2,000 patient service centers, for patients who prefer to self-collect a specimen, instead of collection by a healthcare provider.

About Quest Diagnostics
Quest Diagnostics works across healthcare to create a healthier world, one life at a time. We connect people, from clinicians to consumers, with laboratory insights that illuminate a path to better health. With a focus on delivering smarter, simpler testing, we help reveal new avenues to identify and treat disease, empower healthy behaviors and improve healthcare management. Quest Diagnostics serves half the physicians and hospitals in the United States and one in three American adults each year, and our nearly 60,000 employees work together to deliver diagnostic insights that inspire actions to transform lives. www.QuestDiagnostics.com

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SOURCE Quest Diagnostics

FAQ

What did the Quest Diagnostics (DGX) national study find about bacterial vaginosis and STI co-infection?

The study found women with bacterial vaginosis had much higher non-viral STI co-infection rates. According to Quest Diagnostics, 12.0% of BV-positive women had at least one STI, compared with 3.8% of BV-negative women, based on testing of over 1.5 million U.S. women.

How much higher are STI odds in BV-positive women according to the 2026 Quest Diagnostics (DGX) study?

BV-positive women showed substantially increased odds of several STIs. According to Quest Diagnostics, adjusted odds were 2.8 times higher for chlamydia, 3.8 times for gonorrhea, 3.6 times for trichomonas, and 1.9 times for Mycoplasma genitalium compared with BV-negative women in the national dataset.

What was the sample size and timeframe for the Quest Diagnostics (DGX) BV and STI co-infection study?

The analysis used a very large, recent national dataset. According to Quest Diagnostics, scientists reviewed deidentified, aggregated molecular testing data from more than 1.5 million women across the United States collected between 2022 and 2024, making it the largest national study of its kind.

Does vulvovaginal candidiasis increase STI risk in the Quest Diagnostics (DGX) study?

Vulvovaginal candidiasis alone was not linked to higher STI co-infection risk. According to Quest Diagnostics, while 28.5% of women tested positive for candidiasis and 10.8% for both BV and candidiasis, candidiasis on its own was not associated with increased odds of having an STI.

How do CDC guidelines and the 2026 Quest Diagnostics (DGX) data relate to STI testing in women with BV?

CDC guidelines already recommend STI testing for women with BV. According to Quest Diagnostics, the new data, showing 12.0% co-infection in BV-positive women, supports comprehensive diagnostic approaches and reinforces guideline-based STI testing when BV is identified in clinical practice.

What self-collection services related to bacterial vaginosis has Quest Diagnostics (DGX) introduced?

Quest has expanded access to testing through patient self-collection. According to Quest Diagnostics, in 2024 it introduced self-collection services for bacterial vaginitis and other common genital tract infections at more than 2,000 patient service centers for individuals preferring self-collected specimens.

What are key strengths and limitations of the Quest Diagnostics (DGX) BV and STI study?

The study’s main strengths are its national scope and large, diverse sample. According to Quest Diagnostics, limitations include reliance on data from a single national laboratory and lack of detailed patient information, such as additional behavioral or clinical risk factors.