Immunogenicity of a highly attenuated MVA smallpox vaccine and protection against monkeypox

PL Earl, JL Americo, LS Wyatt, LA Eller, JC Whitbeck… - Nature, 2004 - nature.com
PL Earl, JL Americo, LS Wyatt, LA Eller, JC Whitbeck, GH Cohen, RJ Eisenberg…
Nature, 2004nature.com
The potential use of smallpox as a biological weapon has led to the production and
stockpiling of smallpox vaccine and the immunization of some healthcare workers. Another
public health goal is the licensing of a safer vaccine that could benefit the millions of people
advised not to take the current one because they or their contacts have increased
susceptibility to severe vaccine side effects. As vaccines can no longer be tested for their
ability to prevent smallpox, licensing will necessarily include comparative immunogenicity …
Abstract
The potential use of smallpox as a biological weapon has led to the production and stockpiling of smallpox vaccine and the immunization of some healthcare workers. Another public health goal is the licensing of a safer vaccine that could benefit the millions of people advised not to take the current one because they or their contacts have increased susceptibility to severe vaccine side effects. As vaccines can no longer be tested for their ability to prevent smallpox, licensing will necessarily include comparative immunogenicity and protection studies in non-human primates. Here we compare the highly attenuated modified vaccinia virus Ankara (MVA) with the licensed Dryvax vaccine in a monkey model. After two doses of MVA or one dose of MVA followed by Dryvax, antibody binding and neutralizing titres and T-cell responses were equivalent or higher than those induced by Dryvax alone. After challenge with monkeypox virus, unimmunized animals developed more than 500 pustular skin lesions and became gravely ill or died, whereas vaccinated animals were healthy and asymptomatic, except for a small number of transient skin lesions in animals immunized only with MVA.
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