Infections

According to the World Health Organization (WHO) infectious diseases are defined as morbidities that are caused by pathogenic microorganisms, namely bacteria, viruses, parasites, or fungi. The diseases can be spread, directly or indirectly, from one person to another [1]. One important viral infectious agent is the human immunodeficiency virus (HIV). In 2022, there were 1.3 million new HIV infections recorded globally [2]. Another important infectious disease is hepatitis C, with 2.2 million new infections in 2022 [2]. These numbers show that infectious diseases play an important role in global health science. One of the most effective ways to battle infectious diseases is prevention reducing the burden of disease in the population through targeted measures. Furthermore, prevention includes all actions that are carried out with the purpose of avoiding, delaying, or making illness less likely. To develop effective preventive measures, it is essential to know the transmission routes of pathogens and risk factors for acquiring disease.

Barbershops have been considered as sources for transmission of distinct infectious agents including blood-borne pathogens such as HIV or hepatitis B virus (HBV) that could hypothetically be acquired via a compromised skin barrier following cuts due to the barbering practice, for instance. But there are other groups of microorganisms such as parasites, bacteria, or fungi that could be transmitted to the customer via contaminated equipment or by direct skin-to-skin contact. One example of parasites that might be acquired in barbershops are ectoparasites such as lice affecting approximately 8–12 million children every year in the USA alone [3]. Besides to the louse infestation, lice can carry pathogens possibly leading to additional (super-) infections [4]. Furthermore, bacteria play a major role as infectious agents, with 33 bacterial pathogens accounting for estimated 7.7 million out of 13.7 million infection-related deaths in 2019 [5] with rising prevalence and incidence of infections due to antibiotic resistance accounting for an estimated 4.95 million deaths all around the globe in 2019 [6]. In addition, fungal infections need to be taken into consideration given that more than 10% of the German population are estimated to be affected by fungal pathogens [7]. Among those, filamentous fungi such as dermatophytes that mainly infect the skin and hair are of relevance as potential infectious agents transmitted in barbershops [8]. Besides that, yeasts and molds can be rather neglected as pathogens causing barbershop-acquired infections.

Barbering practice

Barbershops are playing an important role in today's social life of men who get their hair and beards done. The barbering profession entails various risks, however. Barbers are working with equipment such as non-sterile sharp instruments, that are often reused. Therefore, they pose a possible source for infections given that the barbering procedures can unintentionally damage the skin through abrasions or cuts. Even a simple nick caused by a clipper, razor blade, or shaving knife can allow microorganisms to cross the compromised epithelial barrier of the skin, to enter deeper tissue sites and to lead to an infection causing health issues to the affected customer [9]. Hence, proper cleaning and effective decontamination of the instruments by disinfection or even sterilization are essential to prevent barbershop-acquired infections. In addition, there is a risk for the barbers themselves to become infected since they are also exposed to above mentioned conditions. Viruses such as HIV, HBV, and hepatitis C virus (HCV) can be transmitted via blood [9], making the barbering practice a possible risk factor for infection, especially in high prevalence regions. In addition to the infection routes that come to mind first, there are many other possible sources of infection via certain equipment including combs, hairbrushes, and water spray bottles. But also surfaces of working areas in barbershops could be a source of distinct microorganisms such as bacteria or fungi being transmitted to the customer (but also the barber) via smear infections. Of note, given that in some countries barbershops are places to contact sex workers, this could entail additional risks for sexually transmitted infections [10]. Taking all the above-mentioned conditions into account, both blood and smear infections might hypothetically be acquired in barbershops, whereas transmission can occur both from the barber to the customer and the other way around, from the customer to the barber.

Objective of this review

The aim of this review was to summarize current knowledge regarding barbershop-acquired infections including transmission routes and preventive measures.

Search

The literature search for this article was performed from May 6th, 2024 to June 5th, 2024 using the Medline Database PubMed. An overview of the searching process is shown in Fig. 1. First, the database was searched for the keywords “Infections” and “Barbershops” with the operator “AND” yielding 49 studies. After reading the abstracts, 5 papers were excluded because they met the exclusion criteria. 24 more studies were excluded after further investigation given that they only involved the recruitment of test subjects in barbershops. Finally, a total of 20 studies remained and were included in this systematic review. These were analyzed regarding the described infections. The search was done by one person. No automation tools were used in the process.

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Search process: modified version of the Prisma 2020 flow diagram [11]

Citation: European Journal of Microbiology and Immunology 14, 4; 10.1556/1886.2024.00104

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Inclusion and exclusion criteria

For this review studies addressing barbershop-acquired infections that were available in English were included. All review articles, editorials, and articles in other languages, however, were excluded. Investigations in which test persons were only recruited in barbershops for other studies were also excluded.

Hepatitis viruses

Belbacha et al. conducted a cross-sectional sero-epidemiological study in Moroccan barbershops in 2007 [12]. The team administered questionnaires to the participants in order to evaluate the medical and socioeconomic risk factors for hepatitis acquisition. Hepatitis B and C serum tests detecting hepatitis B surface antigens (HBsAg), hepatitis B surface antibodies (anti-HBs), hepatitis B core antibodies (anti-HBc), and hepatitis C antibodies (anti-HBc) were performed to screen the participants on actual or previous hepatitis B and C infections. In case of positivity, the hepatitis viral loads were quantified by polymerase chain reaction (PCR). The obtained results revealed that working as a barber may not present a significant threat for hepatitis B infection in Morocco given that 28.1% of the 267 tested barbers and 25.1% of their 529 tested clients showed serological evidence of current or past HBV Infections. Furthermore, HCV could be detected in 1.1% of the barbers and 1.3% of the customers by PCR. The authors also assessed distinct characteristics of barbershops including the shaving practices of the barbers and observed that most of the participating barbers changed razor blades for each client. In addition, the study showed a significant association between a lower risk for viral hepatitis and the cleanliness of the barbershops [12].

A study from 2009 examined the risk factors for hepatitis B infections in Egypt [13]. In this 1:1 matched case-control study, 233 participants per group were enrolled. Patients with acute hepatitis B infections were recruited in two fever hospitals in Cairo, whereas patients with acute hepatitis A or acute hepatitis C served as controls. Serum samples were collected and tested for anti-HAV IgM, anti-HBc IgM, HBsAg, and anti-HCV antibodies. For patients with negative anti-HAV and anti-HBc IgM results, the HCV RNA levels were determined by reverse transcriptase PCR. Moreover, a questionnaire including community exposures were filled out by the participants. A noteworthy result of the study was that shaving in barbershops went along with a two-fold increased risk of transmission of HBV (Odds ratio (OR) = 2.4), but not of other hepatitis viruses [13].

Alswaidi et al. conducted a cross-sectional descriptive study in the framework of the mandatory testing for HIV, HBV, and HCV in the Saudi Arabian premarital screening program [14]. Over four months, more than 74,000 individuals were included in this prevalence study resulting in a subsequent case-control study with 270 participants in each cohort. The authors found out that more individuals in the case group had experienced single or multiple cuts during a visit in barbershops or beauty parlours. Participants with single injuries displayed significantly increased risks of HIV, HBV, and HCV infections (OR = 4.17), that were even higher upon multiple cuts (OR = 6.10). Furthermore, many of the participants stated sharing razers with other persons in their household which was also accompanied with an increased risk for acquiring disease (OR = 16.95). Hence, sharing razors and experiencing cuts at barbershops were shown to be the most significant risk factor for the transmission of HIV, HBV, and HCV [14].

In 2010, Eroglu and colleagues performed a study to assess the risk of hepatitis B infections following sharing and reusing razors in Turkish barbershops [15]. To address this, the authors purchased used razorblades from different barbershops in Samsun, Turkey that were tested for HBV DNA by PCR. The results revealed that HBV DNA was detected in 10 (6.6%) out of 151 samples, further underlining that used razorblades can serve as a source for barbershop-acquired HBV infections [15].

In a case control study, Oliveira-Filho et al. investigated the risk for HCV transmission via the shared use of cutting and perforating instruments [16]. Therefore, blood donors were recruited during routine blood collections in Northern Brazil. The plasma samples were screened for anti-HCV antibodies and positive tests were confirmed by measuring the HCV loads applying real-time PCR. In addition, the patients answered a questionnaire to survey possible risk factors for HCV infections. The study revealed that sharing razors at home (OR = 1.99) and the shared use of disposable blades in public places (OR = 2.34) and hence, not only in barbershops, but also in beauty salons and similar establishments constituted risk factors and potential sources of HCV infections [16].

Valois and colleagues investigated HCV infections following cuts in 2014 [17]. The team recruited blood donors in Belém, Brazil and tested the blood samples for anti-HCV antibodies. Positive tests were confirmed by measuring HCV loads applying reverse transcriptase PCR. Among more than 13,700 blood donors, 1.1% of the samples were tested positive for anti-HCV, whereas in 0.8% of cases HCV-RNA was detectable. On the basis of the questionnaires, the team found multiple risk factors for HCV infections, including shared use of razors at home (OR = 1.8) and even more in public places including barbershops and beauty salons (OR = 2.1) [17].

Al-Rabeei and coworkers surveyed the existing knowledge of barbers regarding hepatitis B and C in Yemen [18]. To address this, 234 barbers were interviewed about their knowledge regarding barbershop-acquired infections as well as their working attitude and practice. 72.5% of the questioned barbers were aware that hepatitis infections can spread through the barbers' instruments, whereas 13% of the participants stated that they reused razorblades on different customers, and only 7.7% were vaccinated against hepatitis B [18].

Metwally et al. examined risky behaviors and habits of Egyptian individuals, that may possibly lead to HCV transmission [19]. The authors interviewed 540 HCV cases all over Egypt and assigned them to negative controls of their family contacts. Detection of anti-HCV antibodies was performed with enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase PCR applied for all positive tests. The study showed, that among male participants, shaving at barbershops was associated with a risk of HCV infection that was two times higher as compared to males who were not shaved in barbershops (OR = 2.6) [19].

A study conducted by Mohsen et al. examined risk factors for HCV infections among Egyptians [20]. In a 10-year survey period, test persons were recruited in fever hospitals. The participants were asked to answer questionnaires addressing potential risk factors for viral hepatitis during the 6 months preceding the onset of the symptoms. Additionally, blood samples were collected and tested for anti-HAV IgM, anti-HBc IgM, HBsAg, and anti-HCV antibodies, and additionally for HCV RNA. In line with the yet mentioned studies the team found various independent risk factors for viral hepatitis infections including shaving at barbershops (OR = 8.7). Interestingly, the study detected a ninefold increased risk for HCV infection associated with shaving in barbershops among intravenous drug abusers, while no increased risk was found for non-drug users. The authors hypothesized that some barbershops could serve as meeting places for intravenous drug addicts [20].

Samo and coworkers conducted a study in 2020 addressing the prevalence and risk factors for HBV and HCV infections in Pakistan [21]. The researchers organized screening camps and handed out questionnaires to the participants. Blood samples were tested for HBsAg and HCV using a rapid immunochromatographic test. Positive tests were confirmed by ELISA and PCR. The study revealed various risk factors for HBsAg prevalence such as shaving at saloons (OR = 131.7) as well as for HCV including shaving at barbershops (OR = 120.3). The authors concluded that participants who went for shaving at barbershops were more likely to become infected with HBV and HCV if compared to participants who did not [21].

In 2014, Villar et al. analyzed the prevalences of hepatitis A, B, and C among beauticians including 74 hairdressers in Rio de Janeiro, Brazil and their knowledge regarding hepatitis infections [22]. The team designed a questionnaire addressing knowledge, working attitude and practice and drew blood samples from each participant. The samples were tested for anti-HAV, anti-HBc, anti-HBs, anti-HCV antibodies as well as for HBsAg using ELISA. The analyses revealed prevalences of 73.9% (88 out of 119 beauticians) for anti-HAV, of 0% for HBsAg, of 5.9% for anti-HBc, of 23.6% for anti-HBs, and 0.8% for anti-HCV in the tested beauticians. In the multi-variate analyses, the profession beautician was the only risk factor for person-to-person transmission of HAV infection if compared to hairdressers and manicurists. Furthermore, most beauticians were well informed regarding viral hepatitis as indicated by the fact that 88.2% of the respondents stated that razors and scissors can be potential sources of transmission for viral hepatitis infections [22].

In 2015, Mutocheluh and colleagues examined the knowledge of barbers regarding the transmission modes of hepatitis B and C [23]. The authors performed a cross-sectional survey of 200 barbershops in Ghana using a structured questionnaire. The vast majority of the study participants showed a lack of knowledge concerning the existence of viral hepatitis caused by HBV and HCV, but 97% knew that sharing used razorblades, for instance, constituted risk factors for transmitting HIV. While observing the barbers at practice the researchers also found, that all of the participating barbers had an ultraviolet (UV) radiation cabinet for sterilization, but the majority was not functional, or the barbers did not know how to use it [23].

HIV

In their study from 2009, Arulogun and colleagues examined the risk of HIV transmission during barbering practice in Nigeria [24]. The authors collected data through direct observation of the barbers by using checklists. 37 (84.1%) out of the 45 barbers knew that HIV could be transmitted through the sharing of non-sterile sharp objects, whereas 62.2% did not know that barbers were at risk for acquiring HIV infections through the barbering practice. In 14 (17.5%) out of the 90 observed barbering sessions, the clippers were not disinfected, and accidental cuts were observed in 3 (3.3%) of the sessions. In addition, the authors found that over half of the disinfections were not properly done by the barbers although they were under observation [24].

In 2012, Biadgelegn et al. investigated the awareness, knowledge, working attitude and practice of barbers regarding the potential risk of HIV infections during barbering practice in Ethiopia [25]. The team used pretested questionnaires and observational checklists to analyze the work of the barbers. Additionally, the authors took swab samples from sharpeners in the barbershops for further cultural analyses. The results of the study revealed that 78.9% of the 123 participants had ever practiced sterilization of contaminated sharp objects used in barbering practice. Furthermore, 59.5% of the respondents strongly agreed, that sterilization of sharp objects is necessary in their workplace. Whereas 59 (48%) of the barbers presented appropriate knowledge regarding the usefulness of sterilization, 80% of them did not practice a correct sterilization. In support, isolation of bacteria derived from the commensal skin microbiota before and even after disinfection and sterilization further underscored the poor disinfection or sterilization practices. Moreover, 91 (89.2%) of the barbers stated, that no inspections were carried out in their work area. The authors emphasized the potential risk of transmission of blood-borne disease including HIV during the barbering practices [25].

Zenbaba et al. conducted a study in 2023 investigating the compliance of barbers in Southeast Ethiopia with biological hazard preventive measures [26]. Therefore, the team used a questionnaire consisting of ten questions to examine the barbers' knowledge. 289 (47.1%) of the participants showed good compliance with the biological hazard preventive measures. Only 6.5% of the barbers had a positive attitude towards biological hazard preventive measures, whereas 36% of them were cleaning their work areas after service provision [26].

Ectoparasites

In 1988, a study addressing the prevalence of ectoparasites such as nits and lice in hair samples derived from barbershops was performed in Brazil by Linardi et al. [27]. The researchers collected 475 samples of cut hair in various barbershops, and the nits and lice were counted upon direct inspection. The results revealed that 140 (29.5%) of the samples were infected with lice and/or nits. The prevalence ranged from 6.4% to 54.3% depending on the district locations of the barbershops [27].

Bacterial pathogens

Al Yousef addressed the bacterial contamination of equipment in barbershops [28]. Therefore, swap samples were taken from nine hairdryers in three barbershops in Riyadh, Saudi Arabia, and the total numbers of bacteria grown on solid agar media were determined. The results showed that even in one of the examined barbershops methicillin-resistant Staphylococcus aureus (MRSA) bacteria were found. In addition, higher bacterial burdens were detected if the hairdryers were used for 20 if compared to 10 seconds [28].

Fungi

Uslu et al. conducted a mycological investigation of equipment used in barbershops in Turkey in 2008 [29]. A total of 357 swab samples were taken from barbers' tools and surfaces of the working place in 32 different barbershops and analyzed by culture. In addition, remains in hair combs were collected. Overall, 87 (24.4%) culture-positive samples were obtained of which 37 (25.0%) were from combs, 26 (32.0%) from hairbrushes, 4 (7.7%) from shaving brushes, and 20 (50.0%) from the headrest of chairs. 88.4% of the fungal isolates were non-dermatophytic molds with Aspergillus being the most commonly detected species (40.2%). Furthermore Penicillium spp., Mucor spp., Cladosporium spp., and Alternaria spp. were found. Dermatophytes including Trychophyton rubrum and Trychophyton mentagrophytes were identified in 6.8% of the isolates, whereas yeasts such as Candida albicans (3.4%) and non-albicans species (1.1%) were found in 4.5% of the isolates [29].

SARS-CoV-2 (COVID-19) and hand hygiene measures

Natnael et al. examined hand hygiene practices in barbershops in Ethiopia during the COVID-19 pandemic [30]. Therefore, a facility-based cross-sectional study was implemented, including 410 barbers and beauty salon workers. To collect data a questionnaire and observational checklists were used. The team was able to show, that 73.7% of the participating barbers and beauty salon workers had good knowledge about SARS-CoV-2 and the preventive hygienic measures. 65.1% of the workers believed in the effectiveness of hand hygiene in preventing COVID-19, and 52.9% of the workers presented a good hand hygiene practice [30].

Sexually transmitted diseases

In 1997, Joesoef and coworkers investigated the prevalence of sexual transmitted diseases (STDs) in various sex establishments in Surabay, Indonesia [31]. Among other venues, the female study population was also recruited in barbershops serving as sex establishments. The sex workers received questionnaires regarding their socioeconomic status, sexual behavior, reproductive health characteristics, and condom use, for instance. In addition, the participants were tested for infections such as gonorrhea, syphilis, chlamydiosis, trichomoniasis, and HIV. 18% of the 150 female sex workers tested in barbershops were tested positive for chlamydia and 3% for syphilis. The authors were able to show with their study that the percentage of female sex workers in barbershops with any of the mentioned infections (25% out of 149) was relatively low compared to other sex establishments in Indonesia such as brothels (48% out of 696) and street prostitution venues (42% out of 192) [31].

Summary of the findings

The results of this review show that the risk of infections that might be acquired in barbershops is of medicinal relevance per se. Most studies included in this review addressed blood-borne infections caused by HBV, HCV, and HIV, and identified shaving and experiencing cuts in barbershops as risk factors for transmitting respective viruses, whereas sharing (particularly not-disinfected) razors even increased the risk [12–21]. One needs to take into consideration, however, that the risk for an infection with blood-borne infectious agents depends on i.) the viral loads of the blood derived from the index patient/individual the razor blade was contaminated with; ii.) the extent of contamination; iii.) the duration of exposure of the blood-contaminated razor blade or equipment to environmental conditions before further use and subsequent cut in the following customer; on the iv.) immune status and v.) the degree of the compromised skin barrier of the shaved person upon the cut, for instance. Notably, in some geographic locations barbershops also serve as contact places for sex workers, which represents an additional risk factor for the transmission of STDs including syphilis, gonorrhea, and chlamydia – for which representative and detailed investigations are missing [21]. Further studies addressed other pathogens than blood-borne and venereal infectious agents that might be acquired in barbershops and detected ectoparasites such as lice, resistant opportunistic drug-resistant pathogenic bacteria such as MRSA, and diverse fungi including yeasts, molds, and dermatophytes such as Trichophyton species [15, 27–29]. Several studies examined the practice, knowledge, and compliance of the barbers regarding biological hazard preventive measures and showed, that there were country-dependent differences in hand hygiene practices and knowledge regarding infections, mode of transmission of the infectious agents, and hygienic preventive measures [18, 22–26, 30].

Limitations of the survey

One of the biggest limitations of this review is the heterogeneity of studies coming from various countries with very different hygienic and sanitary standards. In fact, most studies were conducted in low- and middle-income, but not in high-income countries. For example, in the study from Ghana all participating barbers had an UV radiation sterilizer cabinet for sterilization [23], while in the study from Yemen only washing and disinfecting measures were possible options for cleaning the instruments [18]. The study from Ethiopia even found, that there were no sinks or running water in any of the participating facilities [25]. Most of the studies addressing HIV, HBV, and HCV were performed in high-prevalence countries having a significant impact of the risk of transmission in barbershops. Another important limitation of this survey is the fact that the literature search was done by a single researcher only and therefore, despite the highest diligence, research mistakes cannot be ruled out. Another limitation is, that the review was conducted as broad as possible, but there might be relevant studies that were not found and therefore, were not included in the analysis. Additionally, for some of the found pathogens, there are only few studies from single countries available which limits the informative value on a global level.