Introduction

Poland, located in Central Europe, spans from the Baltic Sea in the north to the Sudetes and Carpathian mountains in the south (Fig. 1). The country has a population of approximately 38 million and represents an upper-middle income European economy, with a GDP per capita of USD 22,056 in 2023 according to World Bank.

Fig. 1
figure 1

Maps showing Poland (dark green) with voivodeship boundaries and its location within the European Union (light green), including main cities referenced in the text. Composite created in Inkscape (version 1.4.1; https://inkscape.org) using Voivodeships of Poland.svg by Odder (Wikimedia Commons; CC BY-SA 4.0; https://commons.wikimedia.org/wiki/File: Voivodeships_of_Poland.svg) and EU-Poland (orthographic projection).svg by Rob984 (Wikimedia Commons; CC BY-SA 4.0; https://commons.wikimedia.org/wiki/File: EU-Poland_(orthographic_projection).svg).

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Polish legislation enacted on December 5, 2008, mandates the prevention and control of infectious diseases and requires hospitals to maintain registers of so-called alert pathogens1. These include certain fungi, such as fluconazole-resistant Candida, Aspergillus, and pathogens from blood or cerebrospinal fluid causing invasive infections2. Data from these registers are reported to local public health authorities and then aggregated at the national level. While selected statistics are published in annual epidemiological bulletins, there is no publicly accessible, comprehensive national dataset on invasive fungal infections. Consequently, Poland is absent from the “fungal burden” map published by Global Action For Fungal Infections3 and Leading International Fungal Education4.

Materials and methods

This study aims to estimate the prevalence of clinically significant fungal infections by analysing scientific publications and demographic data from the region.

Sources of published data

This study conducted a comprehensive search of both global (PubMed, Scopus) and local (Index Copernicus, Polish Medical Bibliography) databases to identify relevant literature on the incidence and prevalence of serious mycoses in Poland. The search utilized keywords such as “Poland”, “mycoses”, “fungi”, “infection”, and their Polish equivalents. Retrieved references were managed in Zotero and Mendeley. Papers detailing single cases of fungal infections or those that did not allow for the estimation of mycosis incidence (e.g. studies reporting only person-day counts or lacking data on affected populations) were excluded.

Epidemiological and demographic data presented in the following sections were used as background for estimating the frequency of serious mycoses in Poland, by combining population-level and disease-specific information from national and international sources.

Sources of data on population and its characteristics

General demographic data and information on underlying conditions for mycoses were obtained primarily from publicly available government websites5 and bulletins from the National Health Fund (NFZ)6,7. Additionally, Poland has a centralized system for monitoring certain infectious diseases, including HIV, tuberculosis (TB), and cancers, which publishes data on disease occurrence8,9,10,11.

Data analysis employed a dual approach. The first involved global estimates of fungal infection prevalence within exposed populations, while the second relied on morbidity estimates derived from available publications.

General population data

As of 31 December 2023, Poland’s population was 37,636,508, including 51.7% (19,454,109) females and 19.2% children/adolescents (< 18 years; 7,226,549)12. Women aged 15–49 numbered 8,607,73312 (Fig. 2). Average life expectancy was 74.7 years for men and 82.0 years for women13. The population density was approximately 120/km²14.

Fig. 2
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Population structure by demographic characteristics, sex, and age in Poland, 2023 (Based on the Demographic Yearbook)12; ♂ - males, ♀ - females.

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At the end of 2022, Poland had 896 general hospitals (164,400 beds) and 231 day hospitals (6,500 places for day care)15. There were 6,895,900 hospitalizations in general hospitals, including 108,800 admissions to intensive care units (ICUs). Children and adolescents under 18 years of age represented 17.3% (1,191,400 individuals) of hospitalized patients15. There were 158,900 licensed physicians and 17,900 laboratory diagnosticians15.

Estimating underlying diseases prevalence linked to mycoses

Diseases with immunosuppression. Data from the e-Health Centre indicated that between 2010 and July 2023, 22,043 patients utilized at least two HIV-related healthcare services16. As of 31 December 2023, 19,647 (89.1% coverage) individuals were receiving antiretroviral therapy (ART)17, with 3,429 AIDS cases (2,396 HIV-positive not on ART; 1,033 on ART with CD4 ≤ 200 cells/µL − 5% of those on ART)18. In 2023, 184 new AIDS diagnoses were reported19.

Cancer data were obtained from the Maria Skłodowska-Curie National Research Institute of Oncology (KRN)11,20and NFZ21. In the source reports, prevalence refers to patients alive at year-end, incidence to new diagnoses, and mortality to all deaths regardless of diagnosis year. KRN recorded 181,300 cancer cases and 96,062 deaths in 2022. In 2021, there were 54,552 lung cancers, 3,885 leukaemias (328 in individuals aged 0–19 years), 3,631 non-Hodgkin lymphomas, and 750 Hodgkin’s lymphomas (88 in individuals aged 0–19 years). NFZ data show that 2,012 AML patients received reimbursed chemotherapy in 2022, increasing to 2,195 in 2023, with approximately half also receiving antifungal drugs21.

Data on transplant recipients were obtained from “Poltransplant”22. In 2023, 977 kidney, 523 liver, 179 heart, and 99 lung transplants were performed in Poland. Hematopoietic stem-cell transplants included 1261 autologous and 790 allogeneic procedures22. Additionally, 1,369 corneas were transplanted in 202223.

Pulmonary diseases. In 2023, the National Tuberculosis and Lung Diseases Research Institute (IGiChP) reported 4436 TB cases in Poland, 96.1% (4,265) of which were pulmonary tuberculosis (PTB). Additionally, 32 cases were diagnosed among HIV/AIDS patients24. The estimated prevalence of sarcoidosis is 6.8 per 100,000 population, with 53% of cases involving the lungs25. NFZ data from 2019 recorded 9,963 patients with pulmonary sarcoidosis, including cases with concurrent lymph node involvement26. In 2023, asthma affected 2,066,082 people (1,466,626 adults)27; difficult-to-treat asthma occurs 17% and severe asthma around 3.7% of patients28,29. Monovalent mould sensitization was found in 8.4% of asthma patients, rising to 15.4% in those with severe asthma30. In 2019, chronic obstructive pulmonary disease (COPD) was diagnosed in 454,600 people31, with 43,900 (9.7%) hospitalised32, a proportion within the European range of 6–22%33. NFZ data from 2023 reported 2,816 cystic fibrosis (CF) patients, including 1,680 under 18 years of age34.

Other underlying diseases. In Poland, 3.26 million diabetes cases were reported35, with 12.8% requiring hospitalisation36. The prevalence of gastro-oesophageal reflux disease (GERD) in Europe ranges from 8.8–25.9%37, with similar figures for Poland38. In 2019, the number of cases of liver cirrhosis in Poland were estimated at 8,644 (6,080–11,391)39.

A summary of the main demographic and underlying disease data is provided in Table 1.

Table 1 Population and underlying disease demographics in Poland.
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Estimation of fungal disease burden

Based on the epidemiological and demographic data described in the previous sections, national prevalence or incidence was estimated for each targeted mycosis. Disease-specific rates were obtained from published literature, preferentially from Polish or European studies, and applied to the size of the corresponding at-risk populations in Poland. Where necessary, estimates were adjusted for clinical factors such as treatment status, disease severity, and overlapping risk groups to avoid double counting. In some cases, specific calculation approaches were applied, for example converting lifetime prevalence to annual incidence by dividing by the relevant period of exposure, or correcting for overlaps between conditions such as HIV/AIDS, gastro-oesophageal reflux disease, and liver cirrhosis in oesophageal candidosis estimates. Final burden figures were derived by aggregating estimates across all relevant risk categories. A detailed description of the calculation methodology, including all assumptions and data sources, is available in the Supplementary Data.

For clarity and consistency, the results are presented according to microbiological grouping, starting with yeasts and followed by moulds. Within each group, conditions are ordered by major clinical syndromes. This structure facilitates targeted use of the article as a reference, allowing readers to locate information on a given pathogen category efficiently. In addition, a summary table (Table 2) provides a concise overview of incidence estimates, with averaged ranges to aid readability and facilitate navigation of the Results section.

Table 2 Incidence of fungal infections in Poland. Estimation ranges were averaged for clarity and ease of interpretation.
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Results

Recurrent vulvovaginal candidosis (rVVC). Vulvovaginal candidosis (VVC) is defined as recurrent when at least four episodes per year or three unrelated to antibiotic use occur40,41,42. In an online survey, Foxman et al. found that 29% (France) to 49% (Italy) of women aged 16–65 self-reported a lifetime healthcare diagnosis of VVC40. Another approach to estimating VVC is based on the prevalence among pregnant women in Poland (11–23.5%) and the number of births in 2023 (272,000)43,44. However, pregnancy is only one of three major independent risk factors for VVC, alongside diabetes and broad-spectrum antibiotic use, which are likely to at least double or triple this estimate. Moreover, a German study based on healthcare records estimated a 5.6% VVC prevalence among women aged 18–6045. These different approaches result in a very broad estimated range of VVC cases in Poland, from about 90,000 to 6,000,000 in total, with an annual incidence of 71,000–190,000, or 294,500 when based on the German healthcare data.

To approximate the burden of rVVC, we used the 24.7% recurrence rate found in a Polish study of generally healthy (non-pregnant) women suspected of candidosis46 and the proportion reported in Foxman’s survey40, where 27.7% of women reported at least one vaginal yeast infection and 24.7% of these had rVVC. These yield estimates of 72,742–81,577 and 17,565–33,283 new rVVC cases annually, respectively, depending on the underlying VVC figures used.

For comparison, Denning et al.42 estimated the global burden of rVVC using a fixed prevalence of 6% (range 5–8%) among women over 18 years, excluding those post-menopausal on hormone replacement therapy, which for Poland corresponds to 532,400 cases (443,654–709,846) with approximately 15,211 (12,324–19,718) cases annually.

Oesophageal candidosis (EC). It is estimated that 20% of HIV/AIDS patients with CD4 counts below 200 × 10⁶/µL who are not receiving ART and 5% of those on ART are susceptible to EC47, corresponding to approximately 1462 cases annually. However, a Polish cross-sectional study by Podlasin et al., conducted in the early 2000s and involving 5,156 HIV-positive patients, reported a lower occurrence of fungal infections (mostly EC), although the diagnoses were not all verified and endoscopy was not routinely done48. The study estimated a mean prevalence of 0.29% among patients on ART and 1.22% among those not on ART. Other available data suggest that EC affects 14.5–54.7% of AIDS patients in Poland49,50. This corresponds to 347–1310 (1462) cases EC among HIV/AIDS patients.

Reflux esophagitis is also associated with EC. Takahashi et al. reported a 1.7% prevalence of EC among patients with upper gastrointestinal disease51. A study in northern Poland found that 0.9–2.4% of adults experienced reflux disease symptoms38. Among 30 million adults in Poland in 2023, this suggests a potential 4700 to 12,500 cases of reflux-associated EC. European prevalence estimates of GERD (8.8–25.9% population)37 would increase these figures ten-fold, resulting in 46,000–135,000 cases. Additionally, Verma et al. estimated that around 2% (0.8–5.8%) of patients with liver cirrhosis develop EC52 leading to estimated 69–501 cases of EC. Taking into consideration the overlap between the populations of HIV/AIDS, GERD, and liver cirrhosis patients53,54,55, the estimated number of oesophageal candidosis (EC) cases in Poland is approximately 4,708 to 12,695 cases annually.

Invasive yeast infection/candidosis. An older hospital-based study conducted between 1993 and 1998 identified 95 Candida spp. strains in the bloodstream of 154,856 patients at a major hospital in the Małopolskie Voivodeship, reflecting an incidence rate of 0.061%56. Extrapolating these findings to the national level, with a total of 6,895,900 patients hospitalized in general hospitals57, suggests approximately 4,210 cases of Candida bloodstream infections nationwide.

Recent multicentre studies reported 302 cases of candidaemia (affecting 294 patients), corresponding to an incidence rate of 0.04 cases per 1,000 patient-days in a hospital setting58. Applying this rate in a theoretical estimation model, assuming continuous full occupancy of the 164,400 beds available in Polish general hospitals in 2022 for the maximum of 365 days, yields 60 million patient-days annually and an estimated 2,400 (600–4,200) cases of candidaemia. However, more realistic estimates, derived from two complementary approaches – one based on hospitalized patients in 2022 with an average stay of 5.1 days and the other on a turnover rate of 44.8 patients per bed annually combined with the total number of hospital beds15 – suggest a range of 35.2–37.6 million patient-days annually, corresponding to 1,502 Candida BSI cases annually, with variability (375–2,629) reflecting incidence rate variability across studies.

Invasive candidosis in adult patients is particularly concerning in ICUs, where early detection of BSIs and sepsis is crucial. Studies conducted in various hospitals in Poland report that the incidence of candidaemia in ICUs ranges from 0.08 to 1.3% (mean 0.9%)59,60,61,62. Given that 108,800 patients were hospitalized in ICUs in Poland in 202215, this translates to an estimated 979 cases of Candida BSI (range: 87–1,414). Using a different approach, combining the 6.9–9.8% occurrence of BSIs among ICU patients62,63 with the 7.2% proportion of Candida among healthcare-associated bloodstream infections64, yields an estimated 541–768 cases of Candida BSI annually in Poland. Furthermore, multicentre studies indicate that 30.8% of all Candida BSI cases in hospitals originate in ICUs58. This proportion suggests that the total incidence of candidaemia in hospitals is approximately three times higher than in ICUs, resulting in an estimated 2,654 cases nationwide (range: 282–4,591).

Candida peritonitis. In a three-year study in Szczecin, Candida peritonitis occurred in 1 of 89 peritoneal dialysis patients (1.1%)65. By the end of 2023, Poland had 20,536 dialysis patients, of whom 766 were on peritoneal dialysis66. This suggests an estimated 8 cases of Candida peritonitis among peritoneal dialysis patients nationwide. Additionally, a separate study from Szczecin identified 2 cases of candidal peritonitis among 234 ICU patients (0.85%)60. Extrapolating this rate, suggests approximately 930 cases of Candida peritonitis annualy among ICU patients in Poland.

Cryptococcosis. As reported by Jankowska et al.50 and the ECDC67, cryptococcosis, an AIDS marker disease, was found in 1.4–2.2% of patients, corresponding to 3–4 cases among the 184 new AIDS cases in Poland in 2023. Autopsy studies in Warsaw68,69 and Wrocław70 documented a cryptococcosis prevalence of 8.5–9% among AIDS patients. In 2023, 22 AIDS-related deaths were reported, with two cases likely attributed to cryptococcosis.

Multicentre studies conducted between 2006 and 2007 identified three cases of cryptococcal bloodstream infection, with two caused by Cryptococcus neoformans and one by C. laurentii58. Combined with data from transplant recipients and aplastic anaemia patients71,72,73, approximately 24 cases of non-HIV-related cryptococcosis are estimated in Poland.

Pneumocystosis (PcP). Studies in young immunocompetent hospitalized children showed that 4.1–13.1% of those with pneumonia symptoms tested positive for Pneumocystis jirovecii74,75,76. The interpretation of these findings is uncertain, since a positive result may mean transient carriage or a previous self-limited infection rather than active disease. Nevertheless, it confirms ongoing circulation of P. jirovecii in Poland. In contrast, PcP occurred in 2 of 123 immunocompromised children with aplastic anaemia (1.6%)71.

Podlasin et al. reported PcP rates of 0.19–0.54% among HIV-positive patients on ART and 0.64–1% among those not on ART48, translating to 53–130 PcP cases annually. PcP as an AIDS defining diseases occurs in 19.6–35.6%50,77 with 36–66 estimated cases annually, which corresponds to the above analysis (slightly increasing the estimation to 73–172 cases).

In a clinical trial cohort of patients with CLL or relapsed NHL, the incidence of PcP was 2.5% among those receiving idelalisib (± co-therapy), compared to 0.2% in those treated only with anti-CD20 antibody or bendamustine-rituximab78. Other immunosuppressive regimens used in CLL/NHL, such as Bruton tyrosine kinase inhibitors or intensive chemotherapy, may confer a similar increase in PcP risk. Applying the idelalisib-based incidence rates to the 19,839 CLL cases diagnosed in Poland in 202279, assuming a distribution of 63.3% vs. 36.7% between high-risk and lower-risk regimens, yields an estimated 328 PcP cases in this patient population.

NFZ data on Diagnostic Related Group D18 (atypical pneumonia) recorded only 191 cases of pneumocystosis as a major cause of hospitalizations in 2019, potentially reflecting underreporting due to limitations in ICD-10 coding or diagnostic practices80.

Kolbrink et al. reported a PcP incidence of 10.5 per 100,000 hospitalizations in Germany, with 27.9% involving HIV-positive patients81. Applying this rate to Poland’s 2022 hospitalized population (6,895,900) yields an estimate of approximately 724 PcP cases with approximately 200 expected cases related to HIV, aligning with the calculations above.

Invasive aspergillosis (IA). According to Polish morbidity data from 2009 to 2016, collected by PZH, hospitalization rates for invasive pulmonary aspergillosis (IPA) were analysed across all hospitals, excluding psychiatric and military facilities. The dataset included 4,206 hospitalizations of 2,338 patients, with an average of 1.8 hospitalizations per patient. The annual rate of hospitalizations for IPA was estimated at 4.0 per million (95% CI: 3.0–5.0)82. Extrapolated to 2023, this corresponds to approximately 151 patients annually, with a range of 112 to 188. Additionally, the NFZ analysis of atypical pneumonia identified 141 patients with pulmonary aspergillosis as the primary cause of hospitalization80. However, these figures only reflect primary registrations of aspergillosis, while many additional cases are likely classified under the underlying disease.

Further estimates suggest a substantial number of undiagnosed or misclassified cases in specific at-risk populations. For instance, in patients with lung cancer, the incidence of IPA is estimated at 2.6%83, which translates to approximately 1,418 cases annually. Among recipients of allogeneic hematopoietic stem cell transplantation (alloHSCT)22,71,73,84,85,86,87, the incidence is estimated at 86 cases per year, ranging from 60 to 112. Solid organ transplant recipients contribute an estimated 83 annual cases, with a range of 31 to 13522,88. Patients with COPD represent another significant at-risk group, with 1.3 to 3.9% developing IPA33. Based on 43,900 hospitalizations for COPD reported in 202331, this corresponds to an estimated 1,141 cases annually, with a range of 571 to 1,712. Among children with cystic fibrosis, pulmonary aspergillosis affects 2.4–2.7% of patients89, extrapolating to approximately 40–45 cases annually.

Additionally, in patients with idiopathic pulmonary fibrosis (IPF) and interstitial lung diseases associated with connective tissue disorders, the number of IPA cases in 201926,90 was estimated at 2,582.

Altogether, the estimated annual incidence of IA in Poland is between 4700 and 6000 cases, with a mean of 5350. These findings highlight a significant underdiagnosis of the disease compared to reported figures and underscore the need for improved diagnostic awareness and recording practices to address the true burden of IA in Poland.

Chronic pulmonary aspergillosis (CPA). Based on the PZH dataset, the average annual hospitalization rate for non-IPA aspergillosis was 4.4 per million (95% CI: 3.5–5.2)82, equivalent to 166 patients in 2023 (range: 132–196). However, CPA is primarily managed in outpatient settings. Among patients with PTB including those often misdiagnosed as “unconfirmed TB,” of whom 19% are estimated to have CPA91—the annual incidence of CPA is projected at 1103 cases, with 1003 cases directly attributable to PTB. Furthermore, in the cohort of 9,963 Polish patients diagnosed with pulmonary sarcoidosis26, a CPA prevalence of 6%92 translates to an additional 598 cases. Assuming all COPD-related hospitalizations represent acute exacerbations—a reasonable assumption given that 9.8% of such cases are associated with CPA93—an additional 1377 cases are estimated. This brings the total projected number of CPA cases to 3244.

Allergic bronchopulmonary aspergillosis (ABPA). Denning et al. assessed the prevalence of ABPA in adults with asthma, finding a prevalence rate of 2.5% (range: 0.7–3.5%)94. In Poland, the NFZ reported 1.47 million adults with asthma in 2023, leading to an estimated 36,750 cases of ABPA (range: 10,290–51,450).

European annual reports show that ABPA occurred in 0.7–1.2% of paediatric and 3.1–3.6% of adult cystic fibrosis (CF) patients95,96. Similar prevalence rates were confirmed by a CF centre in Warsaw, where 1.1% of paediatric patients (4/374) were diagnosed with ABPA89. Based on this, an estimated 12–20 of ABPA in children and 35–41 cases in adults with CF were expected in Poland in 2023.

Severe asthma with fungal sensitization (SAFS). A Polish study investigating asthma patients identified monovalent mould sensitization in 8.4% of cases, with rates of 13.1% in the uncontrolled asthma group and 15.4% among those with severe asthma30. Based on 2023 NFZ data27, and estimation from GINA29, this translates to 123,200 asthmatic patients with mould hypersensitivity, and 8,357 SAFS patients in Poland.

Sinus aspergillosis. Data from Kraków (1998–2004) indicate that Aspergillus-related maxillary sinusitis was found in 2.75% (12/436) of patients diagnosed with chronic rhinosinusitis (CRS)97. In Poland, 193,163 individuals were diagnosed with CRS in 202299, which corresponds to an estimated 5,312 cases of sinus aspergillosis annually. However, this figure may be overestimated, because according to the European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS) criteria, when CRS is defined by symptoms confirmed by endoscopy or CT, its prevalence in Europe is 3–6% of the population98,99,100. Applied to the Polish population, this yields 31,050–62,100 CRS cases, corresponding to approximately 854–1,708 cases of sinus aspergillosis.

Mucormycosis. The prevalence of mucormycosis-related hospitalizations in Europe ranges from 0.2 cases per million in Denmark to 95 cases per million in Portugal, with an average of 1.6 cases per million (excluding the Portuguese outlier)101. Applying this average to Poland suggests that approximately 60 cases should be reported annually. A total number of 21 patients with invasive mucormycosis were reported in Polish hematopoietic cell transplantation and paediatric haemato-oncology centres, including 15 out of 7,788 children (0.19%) and 6 out of 5,237 adults (0.11%)102. Based on data from HSCT patients, who, according to Drogari-Apiranthitou et al., account for 4.7% of underlying conditions103, it is estimated that about 52 cases occurred in 2022, aligning with previous population-based estimates.

Fungal keratitis (FK). Keratitis and corneal ulcers accounted for 12.2% of the indications for corneal grafts in Poland104. In 2022, a total of 1394 corneal grafts were performed23. A single-centre study conducted in Katowice, analyzing samples from adults patients with corneal ulcers (characterized by epithelial defects and stromal inflammation), reported 27.4% had culture-confirmed keratitis. Fungi were identified as the causative agent in 7.1% of cases, though interpolation of data from the last three years in the same study suggests this may reach 15%105.

Nowik et al. reported that 42.2% of patients with FK underwent corneal grafting106. This effectively doubles the estimated number of FK cases to between 8 and 17 annually in Poland. Additionally, the use of confocal microscopy could potentially increase the number of diagnosed cases by 30%. The incidence of FK in Poland is estimated to range between 10 and 22 cases annually, corresponding to 0.03–0.06 cases per 100,000 population. Similarly, the estimated annual incidence of fungal keratitis across Europe remains low, at approximately 0.02 cases per 100,000 population107. This European rate would correspond to about 7.5 cases in Poland in 2023.

Deep skin infection. Since 1972, four confirmed cases of chromoblastomycosis have been reported in Poland, three of which were confirmed by culture108. The incidence of this disease is approximately one case every 10 years. Some Polish mycologists believe that sporotrichosis, once common in the late 19th and early 20th centuries in this region of Europe, has disappeared for unknown reasons109. However, a single case of sporotrichosis in a 50-year-old woman, following a mastectomy, has been documented110. A literature survey and analysis of mycetoma cases in Europe from 1980 to 2014 revealed no Polish cases111. Thus, these conditions remain extremely rare in Poland.

Discussion

This article focuses on serious fungal infections, excluding dermatophytosis, Malassezia superficial infections, and oral candidosis. Although these are the most prevalent conditions, they rarely pose significant clinical challenges and are seldom monitored outside specialized studies. Their occurrence in Poland will be discussed separately.

The burden (incidence and prevalence) of fungal disease in Poland was analysed relying primarily on available literature data. An overall summary of all cases is provided, categorized by annual incidence and prevalence, with rates per 100,000.

Estimating the annual incidence of rVVC is challenging due to limited specific data. Direct calculations, such as those by Denning et al.42, involve dividing the total number of cases by the time of exposure, assuming a rough even distribution of cases over that period to estimate annual prevalence.

Indirect estimates rely on limited data and the assumption that approximately one-fourth of VVC cases become recurrent40,46. Most published estimates of VVC are based on general figures, such as Sobel’s claim that 75% of women experience at least one episode in their lifetime41, a broad estimate lacking a defined timeframe and support from population-based cohort studies112, making it largely uninformative.

This analysis relies on two primary European data sources. The first is a survey of respondents’ self-reported lifetime VVC cases by Foxman et al.40, which also required additional calculations by dividing the lifetime period to estimate annual prevalence. The second, a study by Jacob et al.45, analysed 954,000 practitioner-confirmed cases over 2 years, resulting in higher case numbers. Another European study, based on Swedish medical records, reported a low annual VVC incidence of 3.3–4.6 per 1000 person-years113, translating to 29,000–41,000 cases annually in Poland, including 7200–11,400 rVVC cases. These figures likely underestimate the true burden and were therefore omitted, especially as earlier Swedish data indicate a significantly higher VVC occurrence, with at least 80,000 women purchasing antifungal medications in 1999 alone114.

The analysis primarily focuses on women of reproductive age, as VVC incidence decreases threefold post-menopause115. Nonetheless, postmenopausal cases remain significant and should be included in more precise calculations. The incidence of rVVC in this group, however, is mostly unknown but is likely very low.

The estimated rate of candidaemia is 6.6 cases per 100,000 population, which is higher than in some European countries, such as the Netherlands116, but lower than in others, such as Italy117. Estimates for invasive candidosis (IC) in Poland rely primarily on ICU data from single-centre and multicentre studies. The method of triplicating ICU cases to generalize for all hospitalizations is derived from a multicentre hospital study58. Candida BSI infections in this study may be overestimated. One single-centre study, using data from the entire hospital, estimated 4,137 nationwide cases BSI annually (11/100,000) which is even higher118. Paediatric cases of IC remain relatively low, with rates ranging from 0.8 to 10 per million119,120, translating to an estimated 6–72 cases among Poland’s 7.2 million children in 2023. However, the lower estimate is likely an undercount, given that among paediatric cardiac surgery patients, candidaemia incidence ranges from 0.39–0.65%121,122,123, suggesting around 11–18 IC cases annually.

Cryptococcal disease is primarily associated with HIV infection, but generally rare in Poland. A longitudinal study conducted in Radom, identified four cases of cryptococcosis among approximately 14,500 post-mortem examinations performed over an 18-year period (1968–1983)124. Given that the population of Radom averaged around 180,000 during this period, this translates to an annual incidence of 0.11 cases per 100,000, or approximately 41 cases of cryptococcosis in Poland in 2023. This estimate is in contrast to a two-fold higher number based on prevalence from a European survey125, which included non-HIV cases as well.

Polish data on PcP focus primarily on seroprevalence and colonization, rather than clinical cases126,127,128. In immunocompetent adults, Pneumocystis colonization rates are 4% in those aged 20–45 and 10.4% in those over 60. In children aged 1–6 years, colonization rates are notably higher at 24.5%. In respiratory disease patients, Pneumocystis DNA was detected in 16.2% of cases, often attributed to colonization128. Autopsy studies in Warsaw report pneumocystosis frequencies of 11-16.4% among deceased AIDS patients, with 55% of cases diagnosed during life68,69. Coinfection, particularly with viruses, should be considered in PcP patients, potentially masking the more serious diagnosis.

Invasive aspeargillosis, especially pulmonary, ranges from 8.3 to 15.7% among adult HSCT recipients84,85,86 and from 1.6 to 1.9% among pediatric71,73 HSCT recipients, respectively. In 2023, Poland recorded 790 allogeneic HSCT cases. Studies on aspergillosis occurrence in solid organ transplant recipients in Poland are limited. At a Warsaw centre, 3.4% of liver transplant recipients developed invasive aspergillosis (IA)72, and among paediatric liver transplant recipients, 3.6% developed IA; however, when liposomal amphotericin B was used as prophylaxis, this rate was only 0.6%87. An earlier single-centre study reported that 6.7% of heart transplant patients developed aspergillosis129.

Regarding HIV/AIDS patients in Poland, the prevalence of IA varies: Kamiński found that 5.5% of AIDS patients had invasive fungal infections, including 2% with fungal pneumonia, 1.5% with fungal meningitis, and 1.5% with other fungal infections69. Leszczyszyn-Pynka identified Aspergillus meningitis in 1.3% of AIDS patients (1 out of 76) and in 0.35% of HIV patients (1 out of 284)49. Studies of invasive aspergillosis in COPD, acute leukaemia and lung cancer patients have not been published, so these estimates are based on international studies.

The mortality rate among hospitalized aspergillosis cases was remarkably low at approximately 12%82, throwing doubt on the accuracy of the diagnosis of IA.

The marked 35-fold difference gap between reported and estimated IA cases in Poland likely reflects the fact that a proportion of cases, even if clinically recognised, are not reported under aspergillosis but rather coded according to the primary underlying disease or as other respiratory conditions. Additional contributors include masking by co-existing diseases, limited availability and use of antigen and PCR (as culture and microscopy are soinsensitive), and patient deaths prior to establishing a diagnosis.

Mucormycosis is rare in Europe. The estimation was based solely on data from Greece and the available Polish data in HSCT patients, assuming that in Europe and North America, the most common risk factors for mucormycosis are haematological malignancies and organ transplants, while in Asia, diabetes mellitus is far more prevalent130. In Greece, the proportion of mucormycosis risk factors were haematologic malignancy/neutropenia (29.9%), HSCT (4.7%) and other immunodeficiencies (23.4%), diabetes mellitus at 15.9%; immunocompetent patients (after trauma, burns, surgery, accidents) at 22.4%; autoimmune disorders at 7.5%; and other or unknown factors at 8.4%103.

Rare moulds such as Scedosporium prolificans (fungaemia)131 and Fusarium oxysporum (disseminated infection)132 and arthroconidial yeasts Saprochaete clavata133 have been reported as causative agents of invasive infections in Poland, primarily in haematologic patients. A multicentre study by Nawrot et al., documented one case of Fusarium incarnatum infection during the 2006–2007 period58. Extrapolating from the patient-day data for Candida infections, the estimated number of Fusarium cases is approximately nine. Additionally, one case of fusariosis (0.32%) was reported among 308 paediatric HSCT recipients73. Given that there were 2,051 HSCT procedures in 2023, with about 12% involving paediatric patients, this would add approximately one case to the national incidence of fusariosis.

The prevalence of fungal keratitis is influenced by geographic location, socioeconomic status, occupational risk factors (eye trauma), and contact lens use, with higher incidence rates observed in warmer climates. A retrospective study in Poland (2003–2017) involving 45 patients found eye injuries (15 cases), contact lens use (10 cases), corticosteroid use (6 cases), prior ocular surgeries (7 cases), and ocular surface disorders (7 cases) to be the primary risk factors. Filamentous fungi were identified in 55.6% of cases and yeast in 44.4%106.

Conclusions

The analysis of the burden of fungal infections underscores significant gaps in Poland’s national fungal infection reporting systems, highlighting the urgent need for improved surveillance and targeted public health strategies. Key strengths of this study include a comprehensive literature review that covers a wide range of fungal infections and at-risk populations, the integration of both global and local data to estimate infection prevalence, and a focus on serious infections that provide valuable insights for public health interventions.

However, the study also reveals notable weaknesses. These include substantial gaps in national data, particularly for at-risk populations, reliance on rough estimates and indirect data due to the absence of comprehensive surveillance, and the potential underestimation of infection rates - especially for recurrent or less-reported conditions. Limited support from population-based cohort studies further complicates efforts to produce accurate estimates, potentially introducing biases. A major challenge pertains to data concerning at-risk populations, such as individuals living with HIV. Most studies on HIV-related fungal infections only provide aggregate data on new cases, without detailed mortality figures, which prevents a comprehensive understanding of morbidity trends within this vulnerable group.

In Poland, the lack of a unified and reliable approach to recording and analysing fungal infection cases remains a critical issue, despite regulations suggesting otherwise. Control bodies, such as the Supreme Audit Office (NIK), emphasize that infection monitoring and reporting systems in controlled hospitals fail to provide complete data. According to NIK, the submitted summary cases may be significantly underestimated134. This fragmented data collection hampers effective public health monitoring and limits the capacity for preventive measures and timely interventions.

To gradually improve this situation, priority measures could include: increasing healthcare expenditure for the non-culture-based diagnosis and control of mycoses; revising and modernising reporting systems to ensure completeness and accuracy; adopting standardized case definitions and diagnostic criteria based on international and local guidance; planning and funding national surveillance studies; establishing a central reference centre for fungal diseases—with particular focus on invasive mycoses—to coordinate diagnostics, reference testing, and training; and strengthening laboratory capacity for mycological diagnostics, including molecular methods. Regular training for clinicians and infection control teams should also be implemented to improve detection and reporting practices.