Scientists report positive immune response against mpox using a COVID-19 vaccine

Scientists at City of Hope, one of the largest cancer research and treatment organizations in the United States, show that a COVID-19 vaccine developed at the organization's Los Angeles campus also protects against mpox, according to research published in Communications Medicine.

The vaccine was developed in the laboratory of Don J. Diamond, Ph.D., City of Hope professor in the Department of Hematology & Hematopoietic Cell Transplantation and a member of the Hematological Malignancies Research Institute.

In research led by vaccine experts at City of Hope, a novel COVID-19 vaccine candidate (COH04S1) has been found to also elicit a robust immune response to the mpox (formerly known as monkey pox) virus. Humans and nonhuman primates who received COH04S1 generated an mpox virus (MPXV) cross-reactive antibody response similar to individuals who were vaccinated against mpox by the only Food and Drug Administration-approved smallpox/mpox vaccine on the market, JYNNEOS.

In a relevant mouse model, the authors also showed that the novel COVID-19 vaccine provides protection against the mpox virus strain that caused the recent 2022-2023 global mpox outbreak. COH04S1 could represent a new tool for vaccinating against COVID-19 and mpox with just one injection. COH04S1 is licensed to Geovax laboratories (NASDAQ: GOVX) for COVID-19 and mpox.

In 2020, researchers at City of Hope developed a fully synthetic platform of the highly attenuated modified vaccinia Ankara (MVA) vector that is virtually identical to the form used in the JYNNEOS vaccine. MVA is a strain of a type of poxvirus used to deliver genes to cells that help the body figure out how to fight a virus. The scientists established a virtually identical replica of MVA and used it to make a multiantigen COVID-19 vaccine that is now in Phase 2 clinical trials and represents the most clinically advanced MVA-based COVID-19 vaccine.

Because the vaccine uses a poxvirus replica, the team wanted to see if it also protected against mpox, and found that it does. In fact, they found that mice vaccinated with COH04S1 or just the synthetic MVA both were protected from lung infection after being exposed to a globally circulating strain of mpox, further proving that the synthetic MVA shares virtually identical properties to the natural MVA.

While mpox is not an emergency at the moment, it is reemerging in various locales worldwide (Africa and Asia) and other poxvirus strains with pandemic potential could occur in the future. The COH04S1 vaccine could protect against different poxvirus strains and has the potential to be used as a dual vaccine that can be effective against COVID-19 and mpox disease. Furthermore, because the basic vaccine design can be modified, there could be multiple applications in which vaccines are made for other infectious disease indications but always include background protection against mpox.

The researchers also believe that COH04S1 could serve as an alternative to JYNNEOS in the face of a large outbreak or vaccine shortage, as viral vector vaccine production is hard to scale up rapidly. Immunocompromised individuals are more susceptible to mpox infection symptoms. Because COH04S1 uses the synthetic MVA vector that has been safely tested in hematopoietic cell transplant recipients, it could also serve as a much-needed option for this population and other immunocompromised populations, such as people living with HIV and cancer.

The research team is actively moving forward with plans to develop COH04S1 as an alternative to JYNNEOS and are currently producing it in a cell line for vaccinations. They would also like to develop a clinical trial to do a direct comparison of COH04S1 and JYNNEOS to see if there are differences in response rates and mechanisms.

Flavia Chiuppesi, Ph.D., formerly at City of Hope, is the study's lead author. Study author Felix Wussow, Ph.D., City of Hope assistant research professor in the Department of Hematology & Hematopoietic Cell Transplantation, is an inventor and developer of the COVID-19 vaccine, as well as the synthetic vaccine platform, along with Diamond and Chiuppesi. John Zaia, M.D., the Aaron D. Miller and Edith Miller Chair in Gene Therapy at City of Hope, is the paper's second author. Diamond is the principal investigator of these studies and a paid consultant for Geovax.