Scientists and historians working at different universities have reconstructed the genomes of viral strains that were recovered from the “vaccination kits” used during the time of the American Civil War. For this, they applied sophisticated sequencing techniques.
Their study has been published in Genome Biology, in a paper titled, “The origins and genomic diversity of American Civil War Era smallpox vaccine strains.”
Scientists and historians involved in this project are associated with McMaster University, the Mütter Museum, and the University of Sydney.
The study underlines the importance of studying the diversity of wild virus strains, which could feasibly include strains that may protect against a wide range of viruses, including flu or coronaviruses.
The latest discovery may also open up a to a new field of medical history study through the non-destructive examination of materials previously associated with biological samples.
“Understanding the history, the evolution, and the ways in which these viruses can function as vaccines is hugely important in contemporary times,” said evolutionary geneticist Hendrik Poinar, PhD, who is director of the McMaster Ancient DNA Centre, where the work was carried out, and a principal investigator at the university’s Michael G. DeGroote Institute for Infectious Disease Research.
Facts About Smallpox
- Smallpox is caused by variola virus (VARV), a human-specific member of the Orthopoxvirus (OPXV) genus of the Poxviridae.
- Smallpox was one of the most devastating viral diseases ever to strike humankind, killing about three out of every 10 people who were infected.
- Those who survived infection frequently left disabled, blind, or disfigured.
40th anniversary of the eradication of smallpox
- The World Health Organization recently celebrated the 40th anniversary of the eradication of smallpox, the most successful campaign ever attempted.
- In fact, smallpox is the only human infectious disease that humans have managed to eradicate, thanks to widespread coordinated vaccination programs, and the effectiveness of the vaccine itself.
Significance of the Latest Study
“The World Health Organization’s success in eradicating smallpox using vaccinia virus (VACV; 1980) was in part due to the broad protective immunity induced by infection with one OPXV against subsequent infection by another,” the authors wrote.
Yet despite the historical importance of the achievement, little is known about the origins and diversity of viruses used in smallpox vaccination, the team continued.
For their study, researchers used sophisticated techniques developed at the McMaster Ancient DNA Centre to reconstruct and analyze the genomes of virus fragments recovered from vaccination kits used during the Civil War era.
The kits, part of a medical collection at the Mütter Museum of the College of Physicians of Philadelphia, contained lancets and small glass plates for mixing fluid for vaccines that had been collected from blisters of deliberately infected subjects, and tin boxes with sliding lids to contain scab material.
The techniques used by the scientists enabled them to successfully recover viral molecules from both organic sources, such as scab material, and also from the non-destructive sampling of inorganic materials, such as tin boxes and glass slides, which contained no evidence of organic residues.
The authors conclude that their work offers up a novel, non-destructive approach to recovering DNA which can preserve historical medical collection artifacts for further study. “The clear identification and reconstruction of near-complete genomes of VACV from these vaccination kits, which were in use during the American Civil War era, indicates that these strains were circulating within humans and via physician networks prior to the twentieth century.”
And as researchers around the world are working to develop a vaccine against COVID-19, the success of the smallpox campaign, and the findings reported by Poinar and colleagues, point to the value of vaccination, the team reasoned. They suggested other vaccines are waiting to be discovered among the viral relatives of today’s influenza and coronaviruses.