Survey of mpox knowledge, attitudes, and practices among men who have sex with men and their vaccination intention based on Protection Motivation Theory

1.1 Mpox: an emerging public health concern

Mpox has re-emerged as a global public health concern in recent years. It is a zoonotic disease caused by the mpox virus and was first reported in 1970 in the Democratic Republic of the Congo [1]. The virus belongs to the genus Orthopoxvirus within the family Poxviridae [2, 3]. Historically, mpox was largely confined to regions of Central and West Africa, with occasional imported cases reported elsewhere [4, 5, 6, 7]. In May 2022, outbreaks were reported outside Africa, beginning with locally acquired cases in the United Kingdom and Portugal [8, 9]. The rapid global spread prompted the World Health Organization (WHO) to declare mpox a Public Health Emergency of International Concern in July 2022 [10]. In China, the first imported case was reported in Chongqing in September 2022 [11], followed by local transmission reported in 2023. By 31 December 2023, China had reported 1712 confirmed mpox cases across 29 provincial-level administrative divisions [12]. From 02 June 2023 to 30 June 2025, China reported 2769 confirmed cases, including 20 imported cases [13]. These data suggest the sustained risk, and WHO external situation reports also indicate that mpox transmission remains ongoing in multiple settings globally [14]. Since 2022, transmission has shifted from sporadic zoonotic infections to sustained human-to-human spread, with a substantial proportion of reported cases occurring among men who have sex with men (MSM), indicating that close physical contact has played a major role in transmission [15, 16, 17, 18, 19, 20, 21, 22].

1.2 Mpox vaccine

Currently, prevention remains a key strategy for mpox control [13]. Vaccination has been recommended internationally for people at elevated risk, including MSM, healthcare workers, and laboratory personnel [23]. A live, non-replicating vaccinia virus vaccine approved in the United States in 2019 has been used for both pre-exposure and post-exposure prevention [24]. Studies have shown that one or two doses of this vaccine can provide substantial protection against mpox infection [25]. China’s current mpox prevention and control strategy still relies mainly on non-vaccine measures, and there is currently no commercially available mpox vaccine [13]. Therefore, understanding vaccination intention and its associated psychosocial factors remains important, particularly among populations at elevated epidemiological risk.

1.3 Research justification

MSM have accounted for a substantial proportion of mpox cases reported during recent outbreaks in China [12, 13]. This survey was conducted in October 2023, during the early phase of local mpox transmission in China, when public concern was increasing and vaccine availability remained limited. Understanding MSM’s knowledge, attitudes, practices, and vaccination intention during that period may help characterize how this population perceived mpox and vaccination in the early stage of the domestic epidemic.

2.1 Study design and participants

This cross-sectional online survey was conducted in Chongqing, China, in October 2023. The questionnaire was administered through the Wenjuanxing platform and distributed via posters by local Centers for Disease Control and Prevention (CDCs) in three districts of Chongqing. Eligible participants were men aged 18 years or older who self-identified as MSM. Because a population-based sampling frame of MSM was not available, anonymous online recruitment with purposive sampling was used. Similar approaches have been widely used in research involving MSM and other hidden populations [26, 27]. The study protocol was approved by the Institutional Review Board of Nan’an District Center for Disease Control and Prevention (NACDC) (Reference No. 2023002), and electronic informed consent was obtained from all participants. Participation was anonymous and voluntary. No financial compensation was provided for participation. Potential selection bias inherent to online recruitment was acknowledged.

2.2 Measures

Because no widely used validated questionnaire specifically assessing mpox-related knowledge and vaccination intention among MSM in China was available at the time of data collection, a self-developed questionnaire was used, which was developed by the research team considering the epidemiological characteristics of mpox, the study objectives, and the Protection Motivation Theory (PMT) framework. The questionnaire covered five sections: socio-demographic information, knowledge of mpox, attitudes toward mpox, mpox-related practices, and vaccination intention. The instrument demonstrated good internal consistency and construct validity (Cronbach’s α = 0.911; Kaiser-Meyer-Olkin (KMO) = 0.913; Bartlett’s test of sphericity: p < 0.001). The distribution of questionnaire items is shown in Table 1.

Part 1 included socio-demographic variables such as age, ethnicity, number of cohabitants, educational level, monthly income in Chinese Yuan (CNY), marital status, household registration type, place of residence, sexual role identity within MSM (top, bottom, or versatile), pet ownership, self-reported chronic disease, and recent foreign travel. Pet ownership was included because of potential zoonotic exposure. Recent foreign travel referred to travel within the past 21 days.

Part 2 comprised 37 KAP items, including 11 knowledge items, 7 attitude items, and 19 practice items. The knowledge section covered infection sources, transmission routes, and susceptible populations. Each item had three response options (“Yes”, “No”, or “Unclear”). For descriptive analysis, the proportion selecting each response option was reported for every item. For logistic regression, knowledge was analyzed as a binary variable, and participants who answered all 11 items correctly were compared with all other participants. Attitudes toward mpox were assessed using seven items with yes or no response options. Mpox-related practices included sexual practices, sexually transmitted infection history and testing, willingness to receive the mpox vaccine, and reasons for vaccination. “Recently followed mpox-related information” referred to having followed such information within the previous six months. Self-reported chronic disease referred to participant-reported chronic conditions such as hyperlipidemia, diabetes, hyperuricemia, chronic pain, chronic respiratory disease, immunodeficiency-related disease, malignancy, and other chronic diseases. Human immunodeficiency virus (HIV) infection status was collected separately as a self-reported variable (“Yes”, “No”, or “Unclear”).

Part 3 assessed vaccination intention based on PMT. PMT proposes that self-efficacy, response efficacy, perceived susceptibility, and perceived severity are associated with protective motivation and health-related behaviors [28, 29, 30, 31]. In this study, items were developed to reflect these four constructs in the context of mpox. Self-efficacy was intended to capture perceived ability and readiness to undertake preventive or care-seeking behaviors, with example items including “In same-sex relationships, I pay attention to self-protection to prevent infectious disease transmission”, “If infected with mpox virus, I will actively seek medical care at a regular hospital”, and “If the vaccine is available, I can spare time to receive it promptly”. Response efficacy reflected beliefs about the effectiveness of vaccination and related protective actions, with example items such as “Vaccination (JYNNEOS) is effective against mpox”, “Timely vaccination after exposure can reduce symptom severity”, and “Vaccination can protect partners and family members”. Perceived susceptibility referred to participants’ perceptions of their likelihood of infection, and perceived severity referred to the perceived seriousness of mpox infection and its consequences. All PMT-related items were rated on a five-point Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree).

Based on PMT, the following hypotheses were proposed:

H1: Self-efficacy is associated with vaccination intention.

H2: Response efficacy is associated with vaccination intention.

H3: Perceived susceptibility is associated with vaccination intention.

H4: Perceived severity is associated with vaccination intention.

Vaccination intention was assessed using the binary question: “Are you willing to receive the mpox vaccine?”.

2.3 Statistical analysis

Descriptive analyses were conducted for all variables. Categorical variables were summarized using frequencies and percentages. The binary knowledge variable, defined by whether all 11 knowledge items were answered correctly, and vaccination intention were analyzed using binary logistic regression. Reliability and validity of the PMT-based items were assessed using Cronbach’s α and the KMO measure. Structural equation modeling (SEM) was conducted using Analysis of Moment Structures (AMOS) 28.0 (IBM Corp., Armonk, NY, USA) to evaluate the hypothesized associations within the PMT framework. Model fit was assessed using the chi-square/degree of freedom ratio (χ²/df), goodness-of-fit index (GFI), adjusted goodness-of-fit index (AGFI), root mean square error of approximation (RMSEA), comparative fit index (CFI), and Tucker-Lewis index (TLI). All other analyses were performed using IBM SPSS Statistics 26.0 (IBM Corp., Armonk, NY, USA). A two-sided p-value of less than 0.05 was considered statistically significant.

3.1 Sociodemographic characteristics of the participants

A total of 829 MSM were recruited for the study. The majority of participants (80.9%) were between 18 and 35 years old. Most participants (95.5%) were of Han ethnicity, held a bachelor’s or associate degree (67.3%), and were unmarried (87.0%). Regarding sexual role, 29.1% identified as top, 33.7% as bottom, and 37.3% as versatile. Other socio-demographic characteristics are presented in Table 2.

3.2 Influencing factors of knowledge score

Regarding mpox knowledge, 62.6% of participants answered at least eight of the 11 items correctly, whereas 160 participants (19.3%) answered all 11 items correctly. Question 6 had the highest correct response rate (85.3%), whereas Question 1 had the lowest (45.4%). The distribution of responses to the 11 knowledge items is presented in Table 3.

Variables related to socio-demographic characteristics, attitudes toward mpox, and mpox-related practices were entered into a binary logistic regression model, with answering all 11 knowledge items correctly as the dependent variable. Ethnicity (p = 0.023), household registration type (p = 0.002), perceived higher risk of mpox among MSM than in the general population during the recent outbreak (p = 0.030), willingness to hide infection from others if infected with mpox (p = 0.001), having followed mpox-related information within the previous six months (p < 0.001), self-reported HIV infection status (p = 0.013), and observing a partner’s private parts before sexual intercourse (p = 0.003) were significantly associated with knowledge scores. Detailed results are presented in Table 4.

3.3 Influencing factors of vaccination intention

Among all participants, 749 (90.3%) expressed willingness to receive the mpox vaccine, indicating a high level of vaccine acceptance in this population. Among those willing to be vaccinated, multiple response options were provided for their reasons for vaccination. The main reported reasons included self-protection and reducing the risk of infection or complications (96.8%), protecting partners and family members (87.0%), and concerns about skin symptoms or complications as mpox cases increased (71.2%). Detailed reasons are shown in Fig. 1.

Fig. 1.Reasons for willing to vaccinate. R1: To protect themselves, reduce the risk of infection, and prevent complications; R2: To protect themselves, their partners, and their families; R3: Concern about skin symptoms and complications as more mpox cases were reported; R4: Concern about exposing MSM identity after infection. R5: Concern that infection would affect sexual activity; and R6: Other reasons.

Similarly, variables related to socio-demographic characteristics, attitudes, and mpox-related practices were included in the binary logistic regression model to identify factors associated with vaccination intention. In the final model, participants aged 18–35 years had higher odds of reporting willingness to receive the mpox vaccine than those aged >35 years (OR = 2.268, 95% CI: 1.320–3.897, p = 0.003). Participants who reported concern about the current mpox situation among MSM were also more likely to report willingness to receive the vaccine than those who did not (OR = 4.399, 95% CI: 2.590–7.473, p < 0.001).

3.4 SEM model of PMT

A SEM based on PMT was constructed to evaluate the hypothesized associations. The results showed that H1 and H2 were supported, whereas H3 and H4 were not. Self-efficacy was significantly associated with vaccination intention (unstandardized estimate = 0.071, standardized estimate = 0.136, p < 0.001). Response efficacy was also significantly associated with vaccination intention (unstandardized estimate = 0.047, standardized estimate = 0.117, p = 0.005). Perceived susceptibility and perceived severity were not significantly associated with vaccination intention. The final model showed acceptable overall fit (χ²/df = 2.660, GFI = 0.975, AGFI = 0.959, RMSEA = 0.045, CFI = 0.987, TLI = 0.981). The SEM items and path coefficients are shown in Fig. 2.

Fig. 2.Results of structural equation model.