Addressing Vaginitis Co-infections through Routine NAAT Testing

Vaginitis affects more than 21 million women annually in the United States and will impact most women at least once in their lifetime, making it a leading reason for OB/GYN visits. Approximately 90% of vaginitis cases are caused either individually or in combination by bacterial vaginosis (BV), Candida vaginitis, and Trichomonas vaginalis.^1-4 These infections often have overlapping symptoms with several sexually transmitted infections (STIs), making it difficult to achieve an accurate diagnosis and leaving patients vulnerable to serious health consequences.^5-8 Delayed diagnosis or misdiagnosis of vaginitis can increase a woman’s risk for STIs and pelvic inflammatory disease (PID), as well as potential long-term complications, such as tubal infertility, ectopic pregnancy, and chronic pain.^9-10 We also know that Black and Hispanic women face disproportionately higher risks of BV and STI co-infections.^11-12

As an OB/GYN, I’ve seen firsthand how vaginitis negatively impacts my patients’ health and well-being. Patients commonly feel embarrassed and have significant discomfort that impacts their quality of life. Many have barriers to seeking care such as lack of childcare, or an inability to take time off work, or lack of access to medical care. This can often lead patients to self-diagnosis, possibly mistaking BV for a yeast infection, and treating at home with an inappropriate over-the-counter medication.^4,13 Given the significant prevalence of vaginitis and its potential harm on a woman’s reproductive health, it is essential for every OB/GYN practice to revisit their strategy for accurate detection and timely treatment.

Concerning Links Between Vaginitis and STIs

A growing body of research reveals the link between STIs and the pathogens that cause most cases of vaginitis. A recent 2024 study from Schwebke et al. found that approximately 1 in 5 women who presented with symptoms of vaginitis also had at least one STI. Additionally, women who tested positive for BV had an STI infection rate double the rate found in women who tested negative for BV. In fact, T. vaginalis (TV) and Mycoplasma genitalium (M. gen) infections were significantly associated with BV.^4,14

Previous research supports these newer findings. One study showed that 85% of individuals with an STI also tested positive for BV or Candida species, and other prospective studies have identified BV as a risk factor for several common STIs, including human papillomavirus, herpes simplex virus, HIV, and gonorrhea.^15,16

These findings demonstrate the necessity of considering potential co-infections when diagnosing and treating patients presenting with vaginal symptoms. In fact, the Centers for Disease Control and Prevention (CDC) recommends that all women with BV undergo testing for STIs.¹⁷ Proactively providing comprehensive testing and detection from the start will help distinguish between the causes of vaginitis and associated STIs and ultimately help limit long-term harm caused by these infections.

Challenges Associated with Traditional Diagnostic Methods Contribute to Negative Patient Outcomes

It is common for patients with vaginitis to present overlapping symptoms with other infections. For instance, abnormal vaginal discharge, vaginal irritation, and pain during urination or sex could be associated with BV, Candida spp., TV, chlamydia, gonorrhea, and M. gen. ^5-8 This makes it difficult for OB/GYNs to correctly diagnose vaginitis based on clinical factors alone, as evidenced by the nearly 30% of symptomatic women who remain undiagnosed after clinical evaluation.^5,18

Traditional methods for diagnosing vaginitis, such as wet mount, Amsel’s Criteria, gram stain with Nugent Score, and direct probe, are all highly subjective and can miss vaginitis infections. Wet mount can miss up to 45% of TV infections, and Amsel’s Criteria has sensitivity ranges of between 37% and 70% for BV.^19-20 Additionally, vaginitis testing with direct probe requires the results to be interpreted by a trained professional – which may explain why 32% of BV negative patients receive a false-positive result when tested with direct probe.²¹ In addition to these test performance concerns, some traditional methods require practices to have microscopes and clinicians who are trained to use them – which can be problematic due to various limitations on equipment or staffing.^18,20

The shortcomings of these traditional testing methods are complex, subjective and ineffective, often leading to misdiagnosis and incorrect treatment. Many cases that rely on these diagnostic methods are not successfully resolved the first time, ultimately requiring patients to return to their doctor’s office for several follow-up appointments before receiving the correct diagnosis.^5,22-23 One study found that 47% of women with vaginitis received one or more inappropriate prescriptions, and 34% of women without BV, vulvovaginal candidiasis (VCC), or TV were prescribed antibiotics and/or antifungals.²⁴

Effectiveness of Nucleic Acid Amplification Testing to Diagnose Vaginitis and STI Co-Infections

Delivering the right diagnoses for patients starts with using the right tests. Each case of vaginitis has its own treatment recommendations, so it’s critical for women to receive an accurate diagnosis from the outset. Nucleic Acid Amplification Testing, also known as NAAT, offers superior diagnostic abilities compared with conventional methods for detecting vaginitis. By analyzing small amounts of RNA from vaginal specimens to identify microorganisms, NAAT delivers higher sensitivity and specificity while detecting multiple infections in symptomatic women with a single vaginal swab.^{23, 25}

NAAT can detect 3 times more mixed infections, and at a higher frequency, than traditional diagnostic methods, such as wet mount and Amsel’s Criteria.²⁶ NAAT also has been proven effective at detecting the pathogens that cause 90% of vaginitis cases, and it is cleared by the FDA and recommended by the CDC and ACOG for vaginitis detection.^9,27-30

In combination with the improved performance of NAAT, OB/GYNs can use single swab specimen collection. A vaginal swab can detect multiple infections and disease states with just one sample, streamlining the collection process for both patients and health care providers. This method also misses fewer than 1% of infections vs. urine samples, which can miss up to 10% of infections.^31-32

The Path Forward

Comprehensive diagnostic testing is essential for improving accuracy in evaluating and treating vaginitis and STIs. OB/GYNs should consider the full implications of co-infections when considering diagnostic options for patients. Combined with use of a single swab for sample collection, NAAT enables OB/GYNs to identify co-infections effectively (including additional pathogens of interest not targeted in the initial test), eliminating diagnostic ambiguity, and facilitating evidence-based treatment approaches. Given that delayed or misdiagnosed vaginitis and STIs can increase risks for conditions such as PID and infertility, adopting NAAT in routine gynecologic care is crucial. As this testing method becomes more integrated into routine practice, OB/GYNs can streamline clinical workflows, decrease patient callbacks for re-collection, minimize unnecessary treatments, and improve overall patient health and well-being.

By embracing NAAT for vaginitis detection, we can move closer to an era of precision medicine in women’s health – where every patient receives the right diagnosis and the right treatment the first time.

References

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