China's National Medical Products Administration has approved the country's first monkeypox vaccine to enter Phase I clinical trials, marking a significant milestone in China's infectious disease prevention efforts. The modified vaccinia virus Ankara (MVA)-based live attenuated vaccine, independently developed by Shanghai Institute of Biological Products Co (SIBP) under China National Pharmaceutical Group Corporation, is now recruiting volunteers at Henan Infection Diseases Hospital in Zhengzhou.
The clinical trial aims to evaluate the vaccine's safety and immunogenicity in a diverse population of 120 adult volunteers. The study will include 60 healthy individuals, 30 men who have sex with men (MSM), and 30 individuals living with HIV—reflecting the strategic targeting of high-risk populations identified by global health authorities.
Trial Design and Recruitment Criteria
Recruitment criteria specify that participants must be at least 18 years old with a body temperature below 37.3°C on enrollment day. Those previously vaccinated against smallpox must have been born before 1980. The protocol also requires that male participants and women of childbearing age commit to effective contraception for six months following vaccination, with no plans to conceive during this period.
Dr. Li Wei, lead investigator at Henan Infection Diseases Hospital, emphasized the importance of including diverse populations in the trial. "By including both healthy individuals and those from high-risk groups, we can better understand how the vaccine performs across different populations with varying immune profiles," he stated.
The recruitment window extends until August 21, 2025, allowing sufficient time to enroll the target number of participants across all cohorts.
Vaccine Development and Preclinical Data
The MVA-based vaccine received clinical trial approval on September 9, 2024, making it the first monkeypox vaccine in China to reach this development stage. According to SIBP, the vaccine is produced using a mature cell factory manufacturing process, ensuring consistent quality and stable production capabilities.
Preclinical studies have yielded promising results, demonstrating both safety and potent immunogenicity. Non-human primate models challenged with monkeypox virus after vaccination showed strong immune protection, suggesting potential efficacy in humans.
"The preclinical data indicates robust immune responses comparable to those seen with internationally approved MVA vaccines," noted Professor Zhang Mei, a virologist at the Chinese Center for Disease Control and Prevention who was not directly involved in the vaccine development but is familiar with the research.
Monkeypox Disease Profile and Transmission
Monkeypox is a viral zoonotic disease caused by the monkeypox virus, with transmission occurring through direct contact, respiratory droplets, contaminated objects, and sexual contact. The disease typically begins with a prodromal period lasting one to five days, characterized by fever, chills, malaise, headache, back pain, and swollen lymph nodes.
While sharing clinical features with smallpox, monkeypox generally presents with milder symptoms and a lower mortality rate of 1-10%. A distinguishing clinical feature is lymphadenopathy (swollen lymph nodes), which is not typically observed in smallpox cases.
Global Context and Vaccination Strategy
The World Health Organization issued interim guidance on monkeypox vaccination in August 2022, recommending vaccination primarily for close contacts of monkeypox patients and high-risk groups. These high-risk populations include men who have sex with men, individuals with multiple sexual partners, healthcare workers, researchers, laboratory personnel handling monkeypox diagnostics, and outbreak response team members.
Currently, no monkeypox vaccine has received market approval in China, creating a significant gap in preventive options. Globally, two vaccines have been approved by the U.S. Food and Drug Administration: JYNNEOS (marketed as Imvanex in Europe and Imvamune in Canada) and ACAM2000.
JYNNEOS contains MVA-Bavarian Nordic, a weakened, non-replicating orthopoxvirus similar to the candidate being tested in China. ACAM2000, a live replicating vaccinia virus vaccine, carries higher risks of adverse reactions and is not suitable for all populations.
Implications for Public Health
The development of a domestic monkeypox vaccine represents a significant advancement for China's public health infrastructure and vaccine self-sufficiency. If successful through all clinical phases, the vaccine could provide a critical tool for preventing monkeypox outbreaks in China and potentially in other regions through international partnerships.
Professor Liu Jian, an epidemiologist at Peking University, commented on the broader implications: "Having a domestically developed vaccine provides greater control over supply chains and distribution, which is essential for rapid response during outbreaks. It also potentially offers a more cost-effective option compared to imported alternatives."
As the Phase I trial progresses, researchers will closely monitor immune responses and any adverse events to determine optimal dosing and safety profiles across different population groups. Subsequent phases will likely expand to larger cohorts to further evaluate efficacy and long-term safety before potential regulatory approval.
