Results from this survey provide an updated estimate of self-reported VVC incidence and lifetime prevalence among adult women in the US, confirming that it remains a common infection. Estimating the true public health burden of VVC remains challenging given that it is likely underdiagnosed.
In this study, the annual incidence of self-reported healthcare provider diagnosed VVC (5.2%) and RVVC among those with VVC (4.7%) suggests that ~ 6.8 million women experience VVC and ~ 325,000 experience RVVC in the United States each year, based on an estimated 2019 population of 130,851,717 women age 18 and older 8. Although the number of survey respondents reporting RVVC in the past year was small, these projections show that the number of VVC and RVVC cases may be substantial, in accordance with a previous study that showed a large healthcare burden of nearly 1.4 million outpatient visits and $374 million in direct medical costs related to VVC each year [9]. Our estimate of self-reported healthcare provider diagnosed VVC are remarkably similar to a previous incidence estimate of 5.6% from a telephone survey of U.S. women conducted during 1991–1996 [7, 10]. Similarly, our estimate of RVVC incidence is consistent with an estimate of 5% in 2013 among an internet survey of U.S. and European women with VVC [7, 11].
Robust population-based studies about the lifetime prevalence of VVC and RVVC are scarce. Previously, the most comprehensive study, upon which the recent estimates of the global burden of VVC are based [6], found that the lifetime prevalence of self-reported healthcare provider diagnosed VVC in the United States and 5 European countries ranged from 29 to 49% by country, lower than our estimate of 53% [12]. Also, nearly a quarter of women in the previous study who reported having VVC also reported having RVVC at some point in their lifetime, and the lifetime prevalence of RVVC among all women was 9%; [12] however, our survey did not ask about lifetime prevalence of RVVC.
Strengths and limitations
The overall representativeness of the survey is a strength of our study. Our study’s primary limitation is the self-reported nature of the data, which are subject to misclassification and recall challenges. We chose to ask about provider diagnosed, rather than self-diagnosed VVC, consistent with most of the previous incidence and lifetime prevalence estimates [7, 12], Given the nonspecific nature of VVC signs and symptoms, both overdiagnosis and underdiagnosis by healthcare providers are potential concerns. In addition, some women with VVC likely do not seek medical care because of self-diagnosis and OTC treatment [7], However, the accuracy of self-diagnosis of VVC also tends to be poor, even among women with previous VVC episodes [7, 13]. Another limitation is that the survey did not capture experiences of non-English speakers. Estimating the incidence and lifetime prevalence of VVC is further complicated by many factors likely influencing health status and healthcare seeking behaviors.
Our multivariate analyses of features associated with having VVC in the past year, number of VVC episodes in the past year, and lifetime prevalence of VVC appear to support known clinical risk factors for VVC, namely, diabetes and hormonal contraceptive use (as approximated by partnered status and having children under 18 years old) [3, 14]. Increasing number of healthcare provider visits could indicate poorer overall health status, higher antibiotic use, higher willingness to seek medical care, or easier access to medical care. Similarly, education and income might also be associated with overall health status. Our results do not point to racial/ethnic disparities in VVC after controlling for other potentially related factors. In contrast, a 1995 survey of self-reported provider diagnosed VVC found a higher prevalence of VVC and other vaginal symptoms among Black women compared with white women, though Black women were more likely to seek healthcare [10, 15]. Although we were not able to specifically study RVVC due to small sample sizes, demographic and health-related features associated with increasing number of VVC episodes were similar to those associated with having VVC in the past year, suggesting that explanations unaccounted for in this analysis (for example, genetic susceptibility) may predispose women to developing RVVC [3].
Although geography was not significantly associated with VVC or number of VVC episodes in the multivariate analyses, our results point towards a potentially larger burden of VVC in the Southern U.S. compared with other regions. This phenomenon has not been well described but was also evident in a previous study of nationwide outpatient visit data [7]. Higher rates of outpatient fluconazole prescriptions also support a disproportionate burden of VVC in the South [16].Whether this disparity reflects differences in VVC diagnostic practices or susceptibility to VVC is unknown but deserves further study. Rates of bacterial sexually transmitted infections and antibiotic use are also higher in the South, which could lead to increased risk for developing VVC [17, 18].
Most women (72%) with VVC in this survey reported prescription antifungal use, and a moderate proportion (40%) reported OTC antifungal use, with increasing proportions of women using both prescription and OTC antifungals as number of episodes increased, perhaps reflecting VVC infections not responsive to initial treatment, misdiagnosis of other vaginal infections as VVC, or both. Short-course intravaginal OTC antifungals are often sufficient to treat uncomplicated VVC, whereas prescription antifungals are preferred for severe or recurrent infections or immunocompromised women [19, 20]. Given the self-reported nature of these data, we were not able to determine appropriateness of treatment; however, previous studies show that antifungal drug misuse is common with VVC, both with OTC antifungals to treat self-diagnosed VVC and with inappropriate antifungal prescribing by healthcare providers [2, 21]. In addition to the possibility for prolonged symptoms, inappropriate use of these medications raises broader concerns for the development of antifungal resistance, an emerging clinical and public health problem. This is especially important because the majority of outpatient antifungal prescriptions are fluconazole and likely used to treat VVC [16]. We were not able to identify factors associated with OTC antifungal use or prescription antifungal use with multivariate analyses due to limited sample size. However, we observed bivariate associations with marital status, children in the home, household size, and income, suggesting that socioeconomic status and access to care, among many other factors, likely influence treatment-seeking decisions. Continuing to understand the epidemiology of VVC will be critical in light of the recent approval of ibrexafungerp, the first drug in a new antifungal class in more than 20 years.
