Factors Associated with Immunization Opinion Leadership among Men Who Have Sex with Men in Los Angeles, California

"Opinion leaders have an important role to play in the diffusion of innovations in health, including vaccination messaging."

In communities of men who have sex with men (MSM), there have been recent vaccine preventable disease (VPDs) outbreaks that have resulted in federal, state, and local health department immunisation recommendations in the United States (US); however, immunisation uptake observed among those surveyed is persistently low. This project sought to examine the characteristics associated with opinion leadership for MSM vaccination in the context of an ongoing meningococcal outbreak in Southern California, US. "Opinion leadership is characterised as holding considerable social influence within a network or community, resulting in diffusion of thought, persuasion, and behavior of others." The researchers assessed specific vaccine importance to understand what vaccines were important to opinion leaders and what demographic and behavioural characteristics were unique to them. In addition, they analysed technology and social media use to understand whether these venues may be appropriate channels for opinion leader immunisation interventions, particularly in MSM communities.

Using venue-based sampling, the researchers recruited and enrolled MSM living in Los Angeles (N = 520) from December 2016 to February 2017 and evaluated characteristic differences in sociodemographic characteristics, health behaviours, and technology use among those classified as opinion leaders versus those who were not. Opinion leadership was defined using 5 survey items: (1) "My opinion on vaccines does not seem to count when I talk with others"; (2) "I often influence other's opinions about vaccines"; (3) "When they choose their vaccines, others do not turn to me for advice"; (4) "I often persuade others to get vaccinated"; and (5) "Others rarely come to me for advice about choosing vaccines". Each item was scored on a five-point Likert scale of 1 to 5. The researchers also asked respondents about their past receipt of meningococcal serogroups A, C, W, and Y (MenACWY) and meningococcal B (MenB) vaccines, as well as their opinions on the importance of 13 additional vaccines.

Overall, 70 (13%) were classified as opinion leaders. Vaccination uptake and importance tended to be higher for opinion leaders. Multivariable results revealed that non-Hispanic Black (adjusted odds ratio (aOR) = 2.64; 95% confidence interval (CI): 1.17-5.95) and other race/ethnicity (aOR = 2.98; 95% CI: 1.41-6.29) respondents, as well as those with a history of a sexually transmitted infection (STI) other than HIV (aOR = 1.95; 95% CI: 1.10-3.48), were more likely to be opinion leaders. MenACWY (aOR = 1.92; 95% CI: 1.13-3.25) and MenB (aOR = 3.09; 95% CI: 1.77-5.41) vaccine uptake, and perceived importance for these and 7 additional vaccines, were also associated with being an opinion leader.

The finding that Black/African-American MSM were more likely to be classified as opinion leaders compared to their White counterparts is notable, according to the researchers, given the historical disparities in vaccination coverage among racial/ethnic minority groups in the US. These results are also somewhat counterintuitive, they say, given the documented skepticism regarding biomedical health interventions among Black/African-American MSM. One possible explanation is the intense outreach and engagement to communities of colour during the ongoing meningococcal outbreak in Southern California. "Capitalizing on this association and establishing partnerships with minority community leaders may be especially important considering vaccination coverage disparities between racial/ethnic minority and White adults."

The fact that opinion leaders were more likely to have been diagnosed with an STI compared to non-opinion leaders can be explained by the fact that MSM previously diagnosed with an STI may have more opportunities to interact with healthcare providers and to engage in conversations explicitly focused on sexual health. Previous research with MSM demonstrates discomfort in discussing sexual practices with healthcare providers. The present findings suggest that building partnerships - resulting in, say, the co-location of health promotion activities, STI services, and immunisation services - could be an effective strategy for increasing vaccination and other preventive health interventions among MSM. Another fruitful approach could be engaging HIV-positive MSM in vaccination-related health promotion. Regular engagement with the healthcare system may enable these men to become aware of vaccine preventable disease outbreaks more quickly and to disseminate this information to other MSM.

The study found that both opinion leaders and non-opinion leaders, respectively, had high proportions of Facebook use (85.7% and 86.6%), daily email use (92.8% and 90.9%), daily phone use (98.6% and 98.9%), and daily social media use (95.3% and 89.4%). In addition, the majority of opinion leaders and of non-opinion leaders reported using the internet to access information about vaccinations (64.3% and 57.6%); 51.4% of opinion leaders and 46.2% of non-opinion leaders reported using the internet to find the locations of vaccination providers. In this context, "The efficacy of social media-based opinion leadership interventions demonstrated by previous HIV prevention studies, suggests the potential for sending and receiving health messages via the internet for the purpose of increasing vaccine uptake."

In conclusion: "This work may be particularly useful in developing and prioritizing future vaccine messages that may be rapidly diffused through MSM communities."