Men who have sex with men (MSM) remain a vulnerable population to HIV/AIDS, facing a dis- proportionately high risk of virus infection worldwide. In Latin America and the Caribbean, data reveal that approximately 2.5 million people were living with HIV in 2019, and during the same year, over 133,000 new infections were identified on the continent, indicating a significant concentrated epidemic [1, 2]. While the HIV prevalence in the general adult population stands at approximately 0.4% in Latin America and 1.1% in the Caribbean, these rates are estimated to be as high as 12.6% in Latin America and 4.5% in the Caribbean among the MSM population [1-3].

Several factors contribute to this heightened vulnerability in this population in the region, including behavioral factors (such as engaging in multiple and casual partners, unprotected anal sex, and complex sexual practices) [1, 4-6], as well as social and structural factors (such as the presence of homophobia, discrimination, difficulties in accessing healthcare services, among others) [1, 5-8].

The fight against HIV/AIDS has gained significant support in recent decades, with measures, such as prevention through post-exposure prophylaxis (PEP), pre-exposure prophylaxis (PrEP), and the availability of HIV self-testing. In the Latin American and Caribbean context, Brazil has been the leading country in investing in HIV prevention. Nevertheless, the number of new infections has only marginally decreased in the past decade and is increasing among key young populations in the country [6, 8].

However, studies indicate that the availability of these strategies, such as PEP and PrEP, may not necessarily translate into increased demand or good adherence [6, 9, 10]. For instance, Brazilian data on PrEP usage reveal a significant drop in follow-up over the years, influenced by factors like the concentration of these measures in urban centers, dispensing focused on hospital services, stigma and prejudice associated with their use, and unawareness of PrEP as a valid and effective prevention method [6, 9, 10].

Hence, understanding the levels of awareness of these preventive strategies is crucial to boost their demand, develop more effective interventions, enhance acceptability, and improve the overall quality of life for Brazilian MSM. Therefore, the aim of this study is to evaluate the knowledge about PEP and PrEP within a sample of MSM in Brazil. The results of this study could serve as the foundation for the development of public policies and health programs geared towards reducing HIV transmission in this vulnerable population.

This is a cross-sectional analytical study that utilized a national online survey conducted among Brazilian MSM in the five administrative regions of the country from September to December 2019. This manuscript was constructed following the STROBE checklist for observational studies.

In the sample of 2,250 MSM participants, there was a noticeable predominance of young adults, with a mean age of 25.74 years. The most represented age group was 21 to 25 years old, accounting for 37.1% of the participants. Notably, the majority of participants had attained a college education or higher, comprising 57.8% of the sample. There was also a higher concentration of participants hailing from the Southeast region of Brazil, making up 50.3% of the total, with a median income of 2,154.5 reais.

Regarding partnership characteristics, a significant portion, 75.2%, was in stable relationships, while 75.7% identified as homosexual. Self-reported HIV prevalence stood at 7.1%, and 31.1% of participants visited healthcare services every 6 months (Table 1). Knowledge about PEP was reported by 1,228 (54.5%) participants, while PrEP was known by 1,044 (46.4%) MSM (Table 1).

Next, we conducted a multivariate analysis to examine the primary factors associated with knowledge about post-exposure prophylaxis (PEP) among MSM users of geolocation-based dating apps in Brazil (n=2250). The crude odds ratios were adjusted for the regions of the country.

According to the multivariate analysis, having an income below the minimum wage increased the likelihood of having a better understanding of PEP by 1.43 times. Identifying as heterosexual or bisexual increased the likelihood of having better knowledge about PEP by 3.83 and 1.89 times, respectively. Knowing one's HIV status increased the likelihood by 2.23 times, and more frequent utilization of healthcare services (twice a year or more) increased the likelihood by 1.80 times (Table 2).

In the analysis of factors associated with PrEP awareness (Table 3), adjustments were also made for the region of Brazil. In this instance, the final model of factors that increased the likelihood of being aware of PrEP resembled the case of PEP, and identifying as heterosexual or bisexual increased the likelihood of having better knowledge about PrEP by 5.08 and 1.93 times, respectively. Knowing one's HIV status increased the likelihood by 2.21 times, and more frequent utilization of healthcare services (twice a year or more) increased the likelihood by 2.02 times (Table 3).

In this study, we identified a convergence of factors associated with higher knowledge of both PEP and PrEP among a sample of Brazilian MSM. These factors encompassed social characteristics (income), personal characteristics (sexual orientation), serological status (HIV status), and structural/social factors (healthcare service utilization).

Interestingly, in our sample, individuals with incomes below the minimum wage had a greater likelihood of being aware of PEP and PrEP, which contradicts findings from other studies conducted in Brazil [13, 14] and other countries [15-18]. There could be several reasons for this unexpected finding. Firstly, some studies suggest that lower income levels may be associated with a higher risk of HIV/AIDS exposure, motivating individuals in such circumstances to seek more information about preventive measures [19, 20].

In Brazil, all HIV/AIDS prevention services are provided free of charge through the Unified Health System (SUS). Therefore, individuals with lower incomes may have more access to healthcare services that are part of community-based HIV/AIDS prevention programs, such as basic health units and public health initiatives. These programs can serve as vital sources of information for individuals with lower incomes, compensating for the expected lack of knowledge [21-23].

Furthermore, our data collection predominantly targeted groups within a social network that are particularly popular among students, young adults, and young individuals. These groups tend to attract and bring together individuals who are often unemployed or financially dependent on their parents/guardians [24-26]. This factor may have significantly influenced the observed result.

Identifying as heterosexual or bisexual was also associated with a higher likelihood of possessing greater knowledge about both PEP and PrEP. This finding contradicts the increased investments of the government in Brazil, typically targeting prevention strategies towards LGBTQ+ populations [6, 25]. However, it may reflect significant social and structural issues, such as the stigma and prejudice surrounding HIV/AIDS as a “gay disease” and internalized homophobia. These factors create barriers that distance non-heterosexual populations from accessing healthcare services and other prevention initiatives [8, 27-29].

Stigmatizing beliefs and attitudes towards HIV/AIDS and sexual orientation can contribute to misconceptions and a lack of accurate information about preventive measures like PEP and PrEP. Individuals facing stigma or discrimination may be less likely to seek or receive comprehensive education on HIV prevention, including knowledge about PEP and PrEP [27-31]. Discrimination against LGBTQ+ individuals in healthcare settings can restrict their opportunities to receive proper education and information about HIV prevention methods. Furthermore, concerns related to disclosing one's sexual orientation can impact the willingness of individuals to engage in discussions about sexual health and preventive measures [8, 12, 25-31]. This scenario is not limited to HIV/AIDS [32] but is also observed in other stigmatizing diseases and conditions affecting non-heterosexual populations. It underscores the need for concerted efforts to promote inclusion, combat discrimination, and provide comprehensive sexual health education that is sensitive to diverse identities and experiences.

Moreover, our study underscores the importance of healthcare services in raising awareness about PEP and PrEP. MSM who sought healthcare services more frequently (2 or 3 times a year, compared to those who sought services only annually) had a higher likelihood of knowing about both PEP and PrEP. This finding aligns with previous studies conducted in Brazil and other countries [6, 8, 13, 17, 33]. Consistency in the frequency of healthcare service utilization can be attributed to various factors contributing to greater knowledge about HIV prevention methods. Frequent access to healthcare services provides more opportunities to receive updated and detailed information about additional HIV prevention strategies. Healthcare professionals can also offer specific counseling and guidance on PEP and PrEP, explaining their benefits, usage, limitations, and effectiveness in HIV prevention. This helps to alleviate fears and barriers associated with their use [6, 8-13].

Furthermore, by seeking healthcare services more diligently, MSM have a higher likelihood of participating in regular HIV testing programs. Awareness of one's serological status is crucial for HIV prevention and can motivate individuals to seek other specialized healthcare resources and services. These settings are more likely to provide detailed information about PEP and PrEP [6, 8, 34].

These findings underscore the importance of pre-test counseling for HIV, which occurs during serological testing. It serves as a crucial opportunity to provide information about prevention strategies, including PEP and PrEP. Therefore, investing in engaging MSM in specialized healthcare services that offer appropriate counseling and guidance can contribute to increasing knowledge and adoption of PEP and PrEP as HIV prevention measures.

Based on our data, we believe that our study has illuminated several key factors associated with knowledge about post-exposure prophylaxis (PEP) and pre-exposure prophylaxis (PrEP) among Brazilian MSM, with special emphasis on lower income levels and sexual orientation (identifying as heterosexual or bisexual). Additionally, our study underscores the crucial role of healthcare services in increasing awareness.

In light of our findings, it is of paramount importance to develop targeted interventions that address knowledge gaps and improve access to PEP and PrEP among MSM. Investing in comprehensive sexual health education initiatives, tailored to diverse identities and experiences, can help combat stigma and discrimination. Furthermore, healthcare providers should prioritize the dissemination of accurate information about PEP and PrEP during serological testing, ensuring that individuals are equipped with the knowledge and resources necessary to make informed choices regarding HIV prevention measures.

This research has several limitations that should be considered. Firstly, the absence of sampling diversification strategies limits our ability to generalize the findings. Secondly, important information was based on self-reported data, which is subject to memory bias without verification through health records. Additionally, our sample is limited to men with internet access and smartphones, which may exclude men with limited resources. Moreover, the use of Facebook may have influenced important characteristics of our sample, such as income and age. However, the study allowed for national coverage, including participants from both major cities and smaller towns, which is crucial for increasing awareness and knowledge about PEP and PrEP.

Our study elucidates the multifaceted factors influencing knowledge about post-exposure prophylaxis (PEP) and pre-exposure prophylaxis (PrEP) among Brazilian MSM. While surprising associations with income and sexual orientation emerged, these underscore the need for more targeted and inclusive HIV prevention efforts.

Knowledge of both measures is influenced by personal, social, and structural barriers. These findings emphasize the importance of personalized approaches for each prevention strategy, considering the individual and social characteristics of MSM.

To improve knowledge and access to PEP and PrEP, it is imperative to combat stigma and discrimination, provide comprehensive sexual health education, and prioritize pre-test counseling during HIV testing. By promoting collaborative efforts among public health initiatives, healthcare providers, and community organizations, we can increase awareness and adoption of PEP and PrEP as crucial HIV prevention measures, ultimately contributing to the well-being of the MSM population in Brazil.

To advance the dissemination and adoption of PEP and PrEP as effective HIV prevention measures among MSM, massive and targeted investments are needed in awareness campaigns, healthcare professional training, and improved access to these technologies. Additionally, it is crucial to consider the personal, social, and structural determinants influencing knowledge and adherence to these strategies in order to develop comprehensive and culturally adapted approaches for Brazilian MSM.