Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating the body's adaptive immunity, they help prevent sickness from an infectious disease. When a sufficiently large percentage of a population has been vaccinated, herd immunity results. Herd immunity protects those who may be immunocompromised and cannot get a vaccine because even a weakened version would harm them. The effectiveness of vaccination has been widely studied and verified. Vaccination is the most effective method of preventing infectious diseases; widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the elimination of diseases such as polio and tetanus from much of the world. However, some diseases, such as measles outbreaks in America, have seen rising cases due to relatively low vaccination rates in the 2010s – attributed, in part, to vaccine hesitancy. According to the World Health Organization, vaccination prevents 3.5–5 million deaths per year.
The smallpox vaccine is used to prevent smallpox infection caused by the variola virus. It is the first vaccine to have been developed against a contagious disease. In 1796, British physician Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox virus. Cowpox served as a natural vaccine until the modern smallpox vaccine emerged in the 20th century. From 1958 to 1977, the World Health Organization (WHO) conducted a global vaccination campaign that eradicated smallpox, making it the only human disease to be eradicated. Although routine smallpox vaccination is no longer performed on the general public, the vaccine is still being produced for research, and to guard against bioterrorism, biological warfare, and mpox.
A biosafety level (BSL), or pathogen/protection level, is a set of biocontainment precautions required to isolate dangerous biological agents in an enclosed laboratory facility. The levels of containment range from the lowest biosafety level 1 (BSL-1) to the highest at level 4 (BSL-4). In the United States, the Centers for Disease Control and Prevention (CDC) have specified these levels in a publication referred to as BMBL. In the European Union, the same biosafety levels are defined in a directive. In Canada the four levels are known as Containment Levels. Facilities with these designations are also sometimes given as P1 through P4, as in the term P3 laboratory.
A biological hazard, or biohazard, is a biological substance that poses a threat to the health of living organisms, primarily humans. This could include a sample of a microorganism, virus or toxin that can adversely affect human health. A biohazard could also be a substance harmful to other living beings.
Mpox is an infectious viral disease that can occur in humans and other animals. Symptoms include a rash that forms blisters and then crusts over, fever, and swollen lymph nodes. The illness is usually mild, and most infected individuals recover within a few weeks without treatment. The time from exposure to the onset of symptoms ranges from three to seventeen days, and symptoms typically last from two to four weeks. However, cases may be severe, especially in children, pregnant women, or people with suppressed immune systems.
The vaccinia virus is a large, complex, enveloped virus belonging to the poxvirus family. It has a linear, double-stranded DNA genome approximately 190 kbp in length, which encodes approximately 250 genes. The dimensions of the virion are roughly 360 × 270 × 250 nm, with a mass of approximately 5–10 fg. The vaccinia virus is the source of the modern smallpox vaccine, which the World Health Organization (WHO) used to eradicate smallpox in a global vaccination campaign in 1958–1977. Although smallpox no longer exists in the wild, vaccinia virus is still studied widely by scientists as a tool for gene therapy and genetic engineering.
In 1978, an outbreak of smallpox in the United Kingdom resulted in the death of Janet Parker, a British medical photographer, who became the last recorded person to die from the disease. Her illness and death, which was connected to the deaths of two other people, led to the Shooter Inquiry, an official investigation by government-appointed experts triggering radical changes in how dangerous pathogens were studied in the UK and named after the panel's leader.
The Institute of Virus Preparations was an agency of the former Soviet Union.
The State Research Center of Virology and Biotechnology VECTOR, also known as the Vector Institute, is a biological research center in Koltsovo, Novosibirsk Oblast, Russia. It has research facilities and capabilities for all levels of biological hazard, CDC levels 1–4. It is one of two official repositories for the now-eradicated smallpox virus, and was part of the system of laboratories known as the Biopreparat.
The Demon in the Freezer is a 2002 nonfiction book on the biological weapon agents smallpox and anthrax and how the American government develops defensive measures against them. It was written by journalist Richard Preston, also author of the best-selling book The Hot Zone (1994), about ebolavirus outbreaks in Africa and Reston, Virginia and the U.S. government's response to them.
Orthopoxvirus is a genus of viruses in the family Poxviridae and subfamily Chordopoxvirinae. Vertebrates, including mammals and humans, and arthropods serve as natural hosts. There are 12 species in this genus. Diseases associated with this genus include smallpox, cowpox, horsepox, camelpox, and mpox. The most widely known member of the genus is Variola virus, which causes smallpox. It was eradicated globally by 1977, through the use of Vaccinia virus as a vaccine. The most recently described species is the Alaskapox virus, first isolated in 2015.
Rahima Banu Begum is the last known person to have been infected with naturally occurring Variola major smallpox, the more deadly variety of the disease.
Smallpox was an infectious disease caused by variola virus, which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) certified the global eradication of the disease in 1980, making smallpox the only human disease to have been eradicated to date.
Lisa Ellen Hensley is the associate director of science at the Office of the Chief Scientist, National Institute of Allergy and Infectious Disease Integrated Research Facility in Frederick, Maryland. She was previously a civilian microbiologist in the virology division of the United States Army Medical Research Institute of Infectious Diseases (USAMRIID). Hensley is one of the premier researchers of some of the world's most dangerous infections, including Ebola hemorrhagic fever, Lassa fever, the coronavirus diseases Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), and smallpox. She has been involved in research uncovering critical mechanisms in the pathogenesis of hemorrhagic fever viruses, and has used those discoveries to develop candidate therapeutic drugs for their treatment.
The monkeypox virus is a species of double-stranded DNA virus that causes mpox disease in humans and other mammals. It is a zoonotic virus belonging to the Orthopoxvirus genus, making it closely related to the variola, cowpox, and vaccinia viruses. MPV is oval, with a lipoprotein outer membrane. The genome is approximately 190 kb. Smallpox and monkeypox viruses are both orthopoxviruses, and the smallpox vaccine is effective against mpox if given within 3–5 years before the disease is contracted. Symptoms of mpox in humans include a rash that forms blisters and then crusts over, fever, and swollen lymph nodes. The virus is transmissible between animals and humans by direct contact to the lesions or bodily fluids. The virus was given the name monkeypox virus after being isolated from monkeys, but most of the carriers of this virus are smaller mammals.
Isao Arita was a Japanese physician, virologist and vaccination specialist who headed the World Health Organization (WHO) Smallpox Eradication Unit in 1977–85. During this period, smallpox became the first infectious disease of humans to be eradicated globally. He and his colleagues were awarded the Japan Prize in 1988 for this work. He also advised the successful programme to eradicate poliovirus from the Western Pacific region.
Keith Rodney Dumbell was a British virologist who worked on research and eradication of smallpox.
John Michael Lane was an American epidemiologist who was a director of the Epidemic Intelligence Service's Global Smallpox Eradication program from 1973 to 1981, and who played a leading role in the eradication of smallpox in 1977.
Gain-of-function research is medical research that genetically alters an organism in a way that may enhance the biological functions of gene products. This may include an altered pathogenesis, transmissibility, or host range, i.e., the types of hosts that a microorganism can infect. This research is intended to reveal targets to better predict emerging infectious diseases and to develop vaccines and therapeutics. For example, influenza B can infect only humans and harbor seals. Introducing a mutation that would allow influenza B to infect rabbits in a controlled laboratory situation would be considered a gain-of-function experiment, as the virus did not previously have that function. That type of experiment could then help reveal which parts of the virus's genome correspond to the species that it can infect, enabling the creation of antiviral medicines which block this function.
