When oral fluid HIVST is regarded as a novel strategy to prevent the occurrence of HIV, its implementation could be highly affected by knowledge and the intention to use the test. Similarly, healthcare workers’ knowledge of and intentions to use HIV self-tests may also be affected by various contextual, demographic, socioeconomic, behavioral, and accessibility factors. Therefore, our study evaluated healthcare workers' knowledge of and intention to use oral fluid for HIV self-testing (HIVST) and associated factors with their knowledge of and intention to use the test. Assessing these predisposing domains and their corresponding factors has dual implications for healthcare workers: the knowledge and intention to use HIVST for themselves and the knowledge and intention to use HIVST for the clients they serve. Our study focuses on the former perspective, which could also address the latter perspective by increasing the proportion of people who know their own HIV status, enrolling in HIV ART programs if they are positive, and suppressing viral loads if they are under treatment to achieve the goals of the Joint United Nations Programme on HIV/AIDS [5].

Accordingly, our study revealed that only approximately four in ten healthcare workers had good knowledge scores on HIVST. Although some healthcare workers may have previous experiences from working in ART units or other related programs in their professional lives, the vast majority of healthcare workers may not have specific access to information about HIVST. This finding implies the need to develop effective HIVST training for healthcare workers. Our findings are comparable with those of studies conducted in South Africa and Australia [9, 18].

Our findings proportion were greater than those of a study conducted in Rwanda with male clinic attendees, which reported that 21% of the participants scored good knowledge of HIV self-testing [19]. The variations might be due to contextual differences in the study population, study setting, and sociodemographic characteristics. Our study focused on health professionals who were already more likely to be familiar with the new update of any strategy, whereas other studies were not health professionals. However, the findings of our study were lower than those of studies performed in Lithuania and Italy, where 75% and 55% of the study participants were aware of oral fluid HIVST, respectively [20, 21]. This discrepancy may arise from the fact that Lithuania and Italy are high-income countries with increased healthcare utilization. Moreover, the study participants from Lithuania and Italy were social media users who might have prior exposure and who could easily access innovative practices. The fact that our research was conducted in Ethiopia, a low-income country, could explain the lack of HIVST promotion, inadequate training on HIVST updates, and limited access to HIVST among healthcare workers in our study.

While a greater proportion of healthcare workers are expected to intend to use HIVST, fewer than a quarter have low scores on the intention to use HIVST. This finding is also lower than the finding from the United Kingdom [21]. This difference could be due to the variation in the availability and accessibility of HIV self-testing kits in the two countries, in which study participants from the UK might obtain HIVST kits easily. Furthermore, differences in income levels, educational levels, and access to healthcare services can potentially influence the intention to use HIVST.

Moreover, our results were lower than those of a prior Ethiopian study, where 80% of healthcare workers were interested in being tested for conventional HIV by themselves [16], and in Zimbabwe, with 73.1% HIVST acceptability [22]. However, our study is different from the previous Ethiopian study [16], which focused on the intention to use oral fluid for HIV self-testing, whereas the Ethiopian study [16] focused on the intention to use conventional HIV testing. This is because we did not find similar studies that intended to use oral fluid for HIV self-testing for comparison. Similarly, our study population differs from the study population of Zimbabwe [22], which differed in terms of adolescents and adults and differences in the implementation and scaling of these new initiatives.

Our study revealed that being male is significantly associated with having a good level of knowledge of HIVST compared with being female. A systematic review of sub-Saharan Africa indicated that men had higher acceptance of HIVST than women did [11]. This could be due to men engage in more sexual activity than females do; thus, they may search for different options for testing, including HIVST. However, studies from Kenya and Tanzania reported that females were more likely to use the HIVST kit compared to males were [13, 17]. This inconsistency could be due to the small sample size and different study population (medical students) with variations in the inclusion criteria in the study of Tanzania. Moreover, differences in sociodemographic and cultural background and the sample size in the case of the Kenya study contributed to the inconsistency with our findings.

This contradiction needs further study. Compared with their counterparts, participants who had prior experience in the use of oral fluid for HIVST and who received support for the implementation of HIVST had increased knowledge. Studies from Spain and Malawi [23, 24] support our findings. This might be explained by the fact that those who previously used HIVST were more likely to know more about the importance of HIVST compared to those who had no experience with tests that may have feared side effects and were unfamiliar with the HIVST kit.

Having experience with multiple sexual partners is also an important factor in a good level of knowledge about oral fluid HIVST. Compared with those who did not have multiple sexual partners, study participants who had multiple sexual partners were more likely to have good knowledge of HIVST. Our findings are consistent with those of studies conducted in China, the United Kingdom, and Thailand [15, 21, 25]. A possible explanation could be that as participants have more sexual partners, the risk of becoming infected with the human immune-deficient virus and other sexually transmitted diseases may increase. Therefore, the likelihood of exploring more testing methods would increase because of the risk.

Study participants who had spouses/partners were more likely to have good knowledge of HIVST oral fluid than those who had no spouse. Corroborating these findings, a study from China, the United Kingdom, and Thailand reported that having sexual partners was associated with knowledge of oral fluid HIVST [15, 21, 25]. Our findings revealed that study participants who had heard of oral fluid via HIVST were more likely to have good knowledge than those with lower knowledge levels. This could be because nearly half of the study participants in this study heard about oral fluid HIVST, and participants could trust HIVST rather than HIV testing from health facilities.

Being 25–29 years old was significantly associated with the intention to use HIVST. Being in this age group could increase the likelihood of experiencing sexual behaviors. Therefore, they may seek testing to determine their status due to exposure to sexual activities. Hospital authorities should take note of this and develop expanded HIV testing options targeting healthcare workers to increase their level of knowledge of HIV status. Likewise, good knowledge about oral fluid HIVST was associated with increased intention to use HIVST. Our findings were consistent with those of a Brazilian study [26]. A possible explanation for this is that to have a solid understanding of HIVST, it is important to clarify misconception and fears about HIVST. In addition, the findings indicate that the underlying low level of knowledge of HIVST indirectly contributes to low intention to use it.

The perception of the high cost of an oral fluid HIVST kit has been identified as an obstacle to intention to use, and participants who perceived a high-cost oral fluid HIVST kit were less likely to use oral fluid HIVST. According to Tanzanian studies, two-thirds of participants expressed a willingness to purchase a publicly accessible self-test kit [17]. This suggests that if the perceived fear of the cost of the HIVST kit is resolved, the uptake and intention of HIVST might increase.