Study: Smallpox Vaccine Provides Immunity to Monkeypox

A joint study by the HKUST and the University of Melbourne in Australia found that vaccination against smallpox produced a strong immune response against the monkeypox virus. Courtesy of HKUST

The Hong Kong University of Science and Technology (HKUST) announced on Sept. 9 the finding, from joint research by the HKUST and the University of Melbourne, Australia, that the immune response induced by vaccinia virus-based smallpox vaccines is cross-reactive with the monkeypox virus in humans. The findings were published in the international scientific journal Viruses.

The research was co-led by Professor Matthew McKay of the University of Melbourne, and Research Assistant Professor Ahmed Abdul Quadeer of the Department of Electronic and Computer Engineering of the HKUST.

In May 2022, the new monkeypox virus was first observed. Over 52,000 cases have been confirmed in more than 90 countries and regions globally.

The research team conducted genomic analysis within weeks of the emergence of the new monkeypox virus strain in order to understand whether the genetic mutation observed in this year’s monkeypox outbreak would affect the immune response to the monkeypox virus produced by the vaccine.

Matthew said that the high effectiveness of the smallpox vaccine against the monkeypox virus had been confirmed in past outbreaks of monkeypox virus, and it is regarded as an important measure in preventing large outbreaks.

However, because the monkeypox virus that caused this year’s outbreak was new, scientific data to prove the vaccine’s protective effect is lacking.

The research team compared the genetic similarities and differences between the vaccinia virus and the new monkeypox virus, especially the part of protein known as “antigen epitope,” which is recognized by T cells that make neutralizing antibodies induced by the vaccine.

The research team found that the immune response targeted the antigenic epitopes of the vaccinia virus and the new monkeypox virus because of their genetic similarities.

The findings may reduce anxiety about the new monkeypox virus.

The research was co-led byResearch Assistant Professor Ahmed Abdul Quadeer (L) of the Department of Electrical and Computer Engineering at HKUST and Professor Matthew McKay (R) of the University of Melbourne. Courtesy of HKUST

“Based on the analysis of the study, we expect that the immune response generated by the smallpox vaccine will still be effective against the new monkeypox virus, same as the monkeypox virus that appeared in the past. Our data further support the use of smallpox vaccines recommended by different health authorities worldwide against the new monkeypox virus,” Ahmed said.

But he also said that while genetic sequencing and immunology data have provided evidence to expect a strong immune response, clinical studies are still needed to determine the exact efficacy of these vaccines against the new monkeypox virus.