What do we know about the smallpox vaccine?
What do we know about the smallpox vaccine?
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Smallpox was among the deadliest viral diseases in human history, killing an estimated 30% of the people infected and leaving many survivors with permanent life changes, such as blindness or disfigurement.** ** The smallpox vaccine developed by Edward Jenner in 1796 is considered the first successful vaccine to be created. In the original version, a patient was infected with another disease, cowpox, to induce an immune response that could protect against smallpox. Smallpox vaccines have evolved over time, with some eventually using a different virus called vaccinia (which is similar to cowpox and less harmful than smallpox) to induce a protective immune response. Since smallpox vaccines are considered live virus vaccines, as opposed to weakened (attenuated) or killed (inactivated), more precautions are required when getting this type of vaccine and there are higher risks of severe side effects. Thanks to extensive global vaccination efforts reaching 80% coverage in each country, smallpox was recognized as eradicated in 1980 by the World Health Organization. This means that the smallpox vaccines no longer need to be routinely given, and many people born after this time have not been vaccinated against smallpox.In July 2020, a report was published in Genome Biology about the origins and genetic diversity of some historical smallpox vaccine strains. The authors have stated that "understanding the history, the evolution, and the ways in which these viruses can function as vaccines is hugely important in contemporary times" and that "this work points to the importance of looking at the diversity of these vaccine strains found out in the wild. We don't know how many could provide cross protection from a wide range of viruses, such as flus or coronaviruses."
Smallpox was among the deadliest viral diseases in human history, killing an estimated 30% of the people infected and leaving many survivors with permanent life changes, such as blindness or disfigurement.** ** The smallpox vaccine developed by Edward Jenner in 1796 is considered the first successful vaccine to be created. In the original version, a patient was infected with another disease, cowpox, to induce an immune response that could protect against smallpox. Smallpox vaccines have evolved over time, with some eventually using a different virus called vaccinia (which is similar to cowpox and less harmful than smallpox) to induce a protective immune response. Since smallpox vaccines are considered live virus vaccines, as opposed to weakened (attenuated) or killed (inactivated), more precautions are required when getting this type of vaccine and there are higher risks of severe side effects. Thanks to extensive global vaccination efforts reaching 80% coverage in each country, smallpox was recognized as eradicated in 1980 by the World Health Organization. This means that the smallpox vaccines no longer need to be routinely given, and many people born after this time have not been vaccinated against smallpox.In July 2020, a report was published in Genome Biology about the origins and genetic diversity of some historical smallpox vaccine strains. The authors have stated that "understanding the history, the evolution, and the ways in which these viruses can function as vaccines is hugely important in contemporary times" and that "this work points to the importance of looking at the diversity of these vaccine strains found out in the wild. We don't know how many could provide cross protection from a wide range of viruses, such as flus or coronaviruses."
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What our experts say
Smallpox was among the deadliest viral diseases in human history, killing an estimated 30% of the people infected and leaving many survivors with permanent life changes, such as blindness or disfigurement.
The smallpox vaccine developed by Edward Jenner in 1796 is considered the first successful vaccine to be created. In the original version, a patient was infected with another disease, cowpox, to induce an immune response that could protect against smallpox.
Smallpox vaccines have evolved over time, with some eventually using a different virus called vaccinia (which is similar to cowpox and less harmful than smallpox) to induce a protective immune response. Since smallpox vaccines are considered live virus vaccines, as opposed to weakened (attenuated) or killed (inactivated), more precautions are required when getting this type of vaccine and there are higher risks of severe side effects.
Thanks to extensive global vaccination efforts reaching 80% coverage in each country, smallpox was recognized as eradicated in 1980 by the World Health Organization. This means that the smallpox vaccines no longer need to be routinely given, and many people born after this time have not been vaccinated against smallpox.In July 2020, a report was published in Genome Biology about the origins and genetic diversity of some historical smallpox vaccine strains. The authors have stated that "understanding the history, the evolution, and the ways in which these viruses can function as vaccines is hugely important in contemporary times" and that "this work points to the importance of looking at the diversity of these vaccine strains found out in the wild. We don't know how many could provide cross protection from a wide range of viruses, such as flus or coronaviruses."
Smallpox was among the deadliest viral diseases in human history, killing an estimated 30% of the people infected and leaving many survivors with permanent life changes, such as blindness or disfigurement.
The smallpox vaccine developed by Edward Jenner in 1796 is considered the first successful vaccine to be created. In the original version, a patient was infected with another disease, cowpox, to induce an immune response that could protect against smallpox.
Smallpox vaccines have evolved over time, with some eventually using a different virus called vaccinia (which is similar to cowpox and less harmful than smallpox) to induce a protective immune response. Since smallpox vaccines are considered live virus vaccines, as opposed to weakened (attenuated) or killed (inactivated), more precautions are required when getting this type of vaccine and there are higher risks of severe side effects.
Thanks to extensive global vaccination efforts reaching 80% coverage in each country, smallpox was recognized as eradicated in 1980 by the World Health Organization. This means that the smallpox vaccines no longer need to be routinely given, and many people born after this time have not been vaccinated against smallpox.In July 2020, a report was published in Genome Biology about the origins and genetic diversity of some historical smallpox vaccine strains. The authors have stated that "understanding the history, the evolution, and the ways in which these viruses can function as vaccines is hugely important in contemporary times" and that "this work points to the importance of looking at the diversity of these vaccine strains found out in the wild. We don't know how many could provide cross protection from a wide range of viruses, such as flus or coronaviruses."
Context and background
There has been interest in learning from the history of smallpox vaccination to inform current vaccination efforts for the COVID-19 pandemic. As of 2020, smallpox is the only disease to be considered eradicated by vaccination.
There are also other vaccines throughout history that have informed recent efforts to develop vaccines for COVID-19 and other diseases. For example, the first inactivated virus vaccine to be developed was for influenza (flu), which later informed vaccine development for other diseases including polio and Hepatitis A. Inactivated virus vaccines are an important advancement because no living virus is present in the vaccine, unlike live attenuated vaccines where a weakened live virus is used.
It is important to remember that while COVID-19 vaccine development draws upon some historical knowledge, COVID-19 vaccine candidates are not live virus vaccines (ex. smallpox vaccines), live attenuated virus vaccines (ex. measles, mumps and rubella vaccines), or inactivated virus vaccines (ex. influenza vaccines). COVID-19 vaccine candidates do not actually contain the virus SARS-CoV-2 that causes COVID-19.
Two of the major COVID-19 vaccine candidates in use today, developed by Pfizer/BioNTech and Moderna, are considered the first successful examples of a type of vaccine known as mRNA vaccines. For more information about different types of vaccines, please see the LearnAboutCOVID19.org glossary.
There has been interest in learning from the history of smallpox vaccination to inform current vaccination efforts for the COVID-19 pandemic. As of 2020, smallpox is the only disease to be considered eradicated by vaccination.
There are also other vaccines throughout history that have informed recent efforts to develop vaccines for COVID-19 and other diseases. For example, the first inactivated virus vaccine to be developed was for influenza (flu), which later informed vaccine development for other diseases including polio and Hepatitis A. Inactivated virus vaccines are an important advancement because no living virus is present in the vaccine, unlike live attenuated vaccines where a weakened live virus is used.
It is important to remember that while COVID-19 vaccine development draws upon some historical knowledge, COVID-19 vaccine candidates are not live virus vaccines (ex. smallpox vaccines), live attenuated virus vaccines (ex. measles, mumps and rubella vaccines), or inactivated virus vaccines (ex. influenza vaccines). COVID-19 vaccine candidates do not actually contain the virus SARS-CoV-2 that causes COVID-19.
Two of the major COVID-19 vaccine candidates in use today, developed by Pfizer/BioNTech and Moderna, are considered the first successful examples of a type of vaccine known as mRNA vaccines. For more information about different types of vaccines, please see the LearnAboutCOVID19.org glossary.
Resources
- Smallpox vaccines (WHO)
- Smallpox Vaccine Basics (U.S. CDC)
- Edward Jenner and the history of smallpox and vaccination (Baylor University Medical Center Proceedings)
- The origins and genomic diversity of American Civil War Era smallpox vaccine strains (Genome Biology)
- Smallpox Vaccine Has Lessons for COVID Vaccine (WebMD)
- History of vaccination (Proceedings of the National Academy of Sciences of the USA)
- Understanding How COVID-19 Vaccines Work (U.S. CDC
- Smallpox vaccines (WHO)
- Smallpox Vaccine Basics (U.S. CDC)
- Edward Jenner and the history of smallpox and vaccination (Baylor University Medical Center Proceedings)
- The origins and genomic diversity of American Civil War Era smallpox vaccine strains (Genome Biology)
- Smallpox Vaccine Has Lessons for COVID Vaccine (WebMD)
- History of vaccination (Proceedings of the National Academy of Sciences of the USA)
- Understanding How COVID-19 Vaccines Work (U.S. CDC
