China's first monkeypox vaccine enters phase I clinical trials

China's first monkeypox vaccine has entered phase I clinical trials at a hospital in Central China’s Henan Province and plans to recruit volunteers aged 18 and above in Zhengzhou, capital of the province.

The modified vaccinia virus Ankara (MVA)-based live attenuated monkeypox vaccine, independently developed by Shanghai Institute of Biological Products Co (SIBP) under China National Pharmaceutical Group Corporation, has received clinical trial approval from China’s National Medical Products Administration. The research team will conduct the phase I clinical trials at the Henan Infection Diseases Hospital in Zhengzhou, according to a statement from the SIBP.

The trial plans to recruit 120 volunteers aged 18 and above, including 60 healthy individuals, 30 men who have sex with men, and 30 individuals living with HIV, according to the statement. Recruitment criteria specify that participants must have a body temperature below 37.3 C on the day of enrollment. Those who have been vaccinated with smallpox should be born before 1980. Male participants and women of childbearing age must have no plans to conceive within six months and must agree to use effective contraception for that duration. The application deadline is August 21, 2025.

Previous reports noted that the vaccine received clinical trial approval from the National Medical Products Administration on September 9, 2024, making it the first monkeypox vaccine in China to be approved for clinical trials, The Paper reported.

As a viral zoonotic disease caused by the monkeypox virus, monkeypox spreads through direct contact, respiratory droplets, secretions, contaminated objects, mother-to-child transmission and sexual contact.

In the one- to five-day prodromal period, infected individuals may experience fever, chills, malaise, headache, back pain, sore throat, shortness of breath and swollen lymph nodes.

Monkeypox shares clinical features with smallpox but presents milder symptoms and a lower mortality rate – between 1 percent to 10 percent. A distinguishing feature is lymphadenopathy (swollen lymph nodes).

In August 2022, the World Health Organization issued interim guidance on monkeypox vaccination, recommending vaccination primarily for close contacts of monkeypox patients and high-risk groups exposed to the virus.

High-risk groups include men who have sex with men, individuals with multiple sexual partners, healthcare workers, researchers, lab personnel handling monkeypox diagnostics, and outbreak response team members.

The safety and efficacy of the MVA-based live attenuated monkeypox vaccine have been demonstrated through extensive clinical data. The vaccine is produced using a mature cell factory manufacturing process, which ensures stable manufacturing and reliable quality, experts said. Preclinical studies have confirmed its safety and its ability to provide strong immune protection against monkeypox virus challenges in non-human primate models, according to the statement from SIBP.

As of now, no monkeypox vaccine has been approved for market use in China.

There are currently two vaccines including JYNNEOS and ACAM2000 approved by the US Food and Drug Administration (US FDA) for the prevention of mpox and smallpox diseases in adults of 18 years of age and older determined to be at high risk for smallpox or monkeypox infection.

JYNNEOS is a live virus vaccine that contains MVA-Bavarian Nordic, a weakened, non-replicating orthopoxvirus. ACAM2000 is a live, replicating vaccinia virus vaccine, which can be shed from the vaccination site and can be spread to other parts of the body or to other people. Due to the risks of serious adverse reactions, ACAM2000 is not suitable for all populations, according to the US FDA.

The JYNNEOS vaccine is marketed as Imvanex in the UK and Europe, and as Imvamune in Canada. All three versions contain the same MVA-based vaccine and are produced by the same manufacturer.