A cross-sectional investigation of factors influencing mpox vaccine hesitancy for students in Southwest China

From July to September 2023, China reported over 1, 400 confirmed cases of mpox transmitted mainly through sexual contact between males. Meanwhile, the percentage of men who have sex with men at universities in southwestern China is increasing every year, which is likely to lead to a potential spread of mpox on campuses. Vaccination is an effective preventive measure against infectious diseases, this study examined the willingness of university students in Southwest China to receive the mpox vaccine and analyzed the factors influencing their decision. A cross-sectional survey was conducted among 7311 university students from 10 universities in Southwest China between August 13 and September 1, 2023. The survey revealed a hesitancy rate of 56.13% toward the mpox vaccine, with the most common reason being concerns about vaccine safety (1407/4104, 34.29%). Univariate analysis identified 13 variables that significantly differed between the vaccine acceptance and vaccine hesitancy groups. Multivariate logistic regression analyses indicated protective factors for vaccine hesitancy, such as sexually transmitted diseases, previous knowledge about mpox, frequent information about mpox, people can get reinfection of mpox, and worries about mpox endemic in China. Additionally, the confidence and convenience dimensions in the 3Cs model were identified as risk factors for mpox vaccine hesitancy. This study found a high rate of vaccine hesitancy among university students in Southwest China regarding the mpox vaccine. Collaboration between university and healthcare departments is recommended to address mpox vaccine hesitancy among college students, thereby promoting their willingness to receive the mpox vaccine.

An open-label, non-randomized study investigating the safety and efficacy of smallpox vaccine, LC16, as post-exposure prophylaxis for mpox

Mpox is an acute exanthematous disease caused by the monkeypox virus. Since May 2022, it has spread as a community-acquired infection, mainly in Europe and the United States, and urgent measures to prevent this infection were also required in Japan. In this study, we investigated the post-exposure prophylaxis of mpox and safety after inoculating the smallpox vaccine. Participants in close contact with patients with mpox were inoculated with "Freeze-dried cell culture Smallpox Vaccine LC16," within 14 days after close contact. Six cases were registered, and all the participants were inoculated. No mpox symptoms or related complications were observed in the participants for 21 days after the close contact. Adverse events due to inoculation, such as rash, fever, lymphadenopathy, and local reaction at the inoculation site (comprising erythema, swelling, induration, and pain) were observed in the participants; however, all inoculation-related events were non-severe and non-serious, and the participants recovered during the 28-day observation period. The findings of this study suggest that inoculation with LC16 is an effective post-exposure prophylaxis in individuals who had close contact with patients with mpox. Further large-scale studies are warranted to validate these findings.

Critical Elements of an Mpox Vaccination Model at the Largest Public Health Hospital System in the United States

In the spring of 2022, mpox spread to non-endemic countries, including the United States. In New York City (NYC), vaccine demand grew as quickly as case counts. With the leadership of the Regional Emerging Special Pathogens Treatment Center (RESPTC) at NYC Health and Hospitals/Bellevue (NYC H+H)-part of the largest public hospital system in the United States-an innovative vaccination model was established that overcame challenges involving health inequities, inadequate access, and lack of vaccine uptake, to successfully administer JYNNEOS vaccines to over 12,000 patients. Transmission has slowed since its peak in August 2022, which has been attributed to successful vaccination campaigns, infection-induced immunity, and behavioral changes among those at highest risk; however, a Centers for Disease Control and Prevention (CDC) assessment released on 4 April 2023 suggests jurisdictions with low vaccination levels (<35%) remain at risk for an mpox resurgence. Here, we summarize the critical aspects of our mpox vaccination model in NYC, which include integration into routine clinical care, prioritization of health equity, and reutilization of COVID-19 vaccination systems, to provide valuable insights for healthcare institutions as we move into the next stage of this ongoing outbreak.

Evaluation of mpox vaccine dose-sparing strategies

The spring-summer 2022 mpox outbreak had over 50,000 cases globally, most of them in gay, bisexual, and other men who have sex with men (MSM). In response to vaccine shortages, several countries implemented dose-sparing vaccination strategies, stretching a full-dose vaccine vial into up to five fractional-dose vaccines. Recent studies have found mixed results regarding the effectiveness of the mpox vaccine, raising the question of the utility of dose-sparing strategies. We used an age- and risk-stratified mathematical model of an urban MSM population in the United States with ∼12% high-risk MSM to evaluate potential benefits from implementing dose-sparing vaccination strategies in which a full dose is divided into 3.5 fractional doses. We found that results strongly depend on the fractional-dose vaccine effectiveness (VE) and vaccine supply. With very limited vaccines available, enough to protect with a full dose approximately one-third of the high-risk population, dose-sparing strategies are more beneficial provided that fractional doses preserved at least 40% of full-dose effectiveness (34% absolute VE), projecting 13% (34% VE) to 70% (68% absolute VE) fewer infections than full-dose strategies. In contrast, if vaccine supply is enough to cover the majority of the high-risk population, dose-sparing strategies can be outperformed by full-dose strategies. Scenarios in which fractional dosing was 34% efficacious resulted in almost three times more infections than full dosing. Our analysis suggests that when mpox vaccine supply is limited and fractional-dose vaccination retains moderate effectiveness, there are meaningful health benefits from providing a smaller dose to a larger number of people in the high-risk population. These findings should inform the public-health response to future mpox outbreaks.