The Race for a Monkeypox Vaccine: Progress and Challenges

Monkeypox is a rare viral disease that has been causing outbreaks in humans since its discovery in the 1970s. Although the disease is usually self-limiting and does not result in severe illness, it can be life-threatening for immunocompromised individuals. The need for an effective vaccine against monkeypox has become increasingly urgent as the disease has spread to new regions and caused larger outbreaks. In this article, we will explore the progress and challenges in the race for a monkeypox vaccine.

The Current State of Monkeypox Vaccines

Currently, there is no specific vaccine for monkeypox that has been approved for use in humans. However, the smallpox vaccine has been shown to be effective in preventing monkeypox in some individuals. This is because monkeypox is closely related to smallpox, and the smallpox vaccine provides some level of cross-protection against monkeypox. But the smallpox vaccine is not without limitations. It can cause serious side effects in some people, and its use is not recommended for certain groups, such as pregnant women and individuals with certain medical conditions.

Development of Monkeypox Vaccines

Several research groups and pharmaceutical companies are currently working on developing a specific vaccine against monkeypox. These vaccines are designed to trigger an immune response that can protect against the virus without causing serious side effects. Some of the approaches being used to develop monkeypox vaccines include:

  • Live-attenuated vaccines: These vaccines use a weakened form of the virus that cannot cause disease in healthy individuals but can still stimulate an immune response.
  • Protein subunit vaccines: These vaccines contain a specific protein from the virus that can trigger an immune response.
  • DNA vaccines: These vaccines use a small piece of DNA from the virus to stimulate an immune response.

Progress in Developing Monkeypox Vaccines

There has been significant progress in the development of monkeypox vaccines in recent years. In 2020, the World Health Organization (WHO) announced that a phase 1 clinical trial of a live-attenuated monkeypox vaccine had been initiated in the United Kingdom. The trial aims to evaluate the safety and immunogenicity of the vaccine in healthy adults.

Another promising development is the use of CRISPR gene editing technology to develop a monkeypox vaccine. Researchers at the University of California, San Diego, have used CRISPR to engineer a live-attenuated monkeypox virus that is safe and effective in animal models. The researchers are now working to translate their findings into a vaccine for humans.

JYNNEOS (Imvamune or Imvanex) and ACAM2000

JYNNEOS (Imvamune or Imvanex) and ACAM2000 are two vaccines that are currently available for preventing monkeypox infection in the United States. These vaccines have been developed based on the vaccinia virus, which is closely related to the monkeypox virus.

JYNNEOS is the preferred vaccine for the current outbreak of monkeypox. It is a live, attenuated vaccine that is administered through a single dose injection. JYNNEOS has been shown to be safe and effective in clinical trials, and it has been approved by the U.S. Food and Drug Administration (FDA) for use in people aged 18 years and older who are at high risk for monkeypox infection, such as laboratory workers, veterinarians, and people who handle infected animals or animal products.

ACAM2000 is another vaccine that is available for preventing monkeypox infection. It is a live, attenuated vaccine that is also based on the vaccinia virus. ACAM2000 was originally developed for use in preventing smallpox, but it has been found to provide protection against monkeypox as well. ACAM2000 is administered through a single dose injection, and it has been approved by the FDA for use in people aged 18 years and older who are at high risk for monkeypox infection.

It is important to note that both JYNNEOS and ACAM2000 may cause side effects, such as fever, headache, muscle aches, and fatigue. Serious side effects, such as allergic reactions, are rare but possible. People who are considering receiving either of these vaccines should talk to their healthcare provider to weigh the risks and benefits and to determine if vaccination is appropriate for their individual situation.

It is also important to note that while JYNNEOS and ACAM2000 are effective in preventing monkeypox infection, they are not a substitute for other preventive measures, such as avoiding contact with infected animals and washing hands frequently. Vaccination should be considered as part of a comprehensive approach to preventing monkeypox and other zoonotic diseases.

Challenges in Developing Monkeypox Vaccines

Despite the progress in developing monkeypox vaccines, there are still several challenges that need to be overcome. One major challenge is the limited funding and resources available for monkeypox vaccine research compared to other infectious diseases such as COVID-19. Another challenge is the limited understanding of the pathogenesis of monkeypox and how the virus interacts with the immune system.


The race for a monkeypox vaccine is an important public health priority. While the smallpox vaccine provides some protection against monkeypox, the development of a specific monkeypox vaccine is crucial to preventing and controlling future outbreaks of the disease. Although there are challenges in developing a monkeypox vaccine, there has been significant progress in recent years. The initiation of clinical trials and the use of innovative technologies such as CRISPR give hope that an effective vaccine against monkeypox will be developed in the near future.