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HealthWorld

Vaccines have saved more human lives than any medical inventions in history

For centuries, humans have looked for ways to protect each other against deadly diseases. From experiments and taking chances to a global vaccine roll-out in the midst of an unprecedented pandemic, immunization has a long history. Vaccine research can raise challenging ethical questions, and some of the experiments carried out for the development of vaccines in the past would not be ethically acceptable today. Vaccines have saved more human lives than any other medical invention in history. Scroll on to take a journey through the last millennium to see how these extraordinary discoveries and achievements have changed our lives. From at least the 15th century, people in different parts of the world have attempted to prevent illness by intentionally exposing healthy people to smallpox– a practice known as variolation (after a name for smallpox, ‘la variole’). Some sources suggest these practices were taking place as early as 200 BCE. In 1721, Lady Mary Wortley Montagu brought smallpox inoculation to Europe, by asking that her two daughters be inoculated against smallpox as she had observed practice in Turkey. In 1774, Benjamin Jesty makes a breakthrough. Testing his hypothesis that infection with cowpox – a bovine virus which can spread to humans – could protect a person from smallpox. In May 1796, English physician Edward Jenner expands on this discovery and inoculates 8-year-old James Phipps with matter collected from a cowpox sore on the hand of a milkmaid. Despite suffering a local reaction and feeling unwell for several days, Phipps made a full recovery. Two months later, in July 1796, Jenner inoculates Phipps with matter from a human smallpox sore in order to test Phipps’ resistance. Phipps remains in perfect health, and becomes the first human to be vaccinated against smallpox. The term ‘vaccine’ is later coined, taken from the Latin word for cow. In 1872, despite enduring a stroke and the death of 2 of his daughters to typhoid, Louis Pasteur creates the first laboratory- produced vaccine: the vaccine for fowl cholera in chickens. In 1885, Louis Pasteur successfully prevents rabies through post-exposure vaccination. The treatment is controversial. Pasteur has unsuccessfully attempted to use the vaccine on humans twice before, and injecting a human with a disease agent is still a new and uncertain method. Pasteur is not a medical doctor. But, despite the risk, he begins a course of 13 injections with patient Joseph Meister, each containing a stronger dose of the rabies virus. Meister survives and later becomes the caretaker of Pasteur’s tomb in Paris. In 1894, Dr Anna Wessels Williams isolates a strain of the diphtheria bacteria that is crucial in the development of an antitoxin for the disease. From 1918 to 1919, the Spanish Flu pandemic kills an estimated 20–50 million people worldwide, including 1 in 67 United States soldiers, making an influenza vaccine a US military priority. Early experiments with influenza vaccines are carried out: the US Army Medical School tests 2 million doses in 1918, but results are inconclusive. In 1937 Max Theiler, Hugh Smith and Eugen Haagen develop the 17D vaccine against yellow fever. The vaccine is approved in 1938 and over a million people have receive it that year. Theiler goes on to be awarded the Nobel Prize. In 1939, bacteriologists Pearl Kendrick and Grace Eldering demonstrate the efficacy of the pertussis (whooping cough) vaccine. The scientists show that vaccination reduces the rates at which children get sick from 15.1 per 100 children to 2.3 per 100. By 1945, the first influenza vaccine is approved for military use, followed in 1946 by an approval for civilian use. The research is led by doctors Thomas Francis Jr and Jonas Salk, who both go on to be closely associated with the polio vaccine. From 1952–1955, the first effective polio vaccine is developed by Jonas Salk and trials begin. Salk tests the vaccine on himself and his family the following year, and mass trials involving over 1.3 million children take place in 1954. By 1960, a second type of polio vaccine, developed by Albert Sabin, is approved for use. Sabin’s vaccine was live-attenuated (using the virus in weakened form) and could be given orally, as drops or on a sugar cube. The oral polio vaccine (OPV) was first tested and produced in the Soviet Union and Eastern Europe. Czechoslovakia becomes the first country in the world to eliminate polio. In 1967, the World Health Organization announces the Intensified Smallpox Eradication Programme, which aims to eradicate smallpox in more than 30 countries through surveillance and vaccination. Eradication means more than the elimination of a disease in a single area – WHO defines it as the “permanent reduction to zero of a specific pathogen, as a result of deliberate efforts, with no more risk of reintroduction”. Smallpox has been mostly eliminated in Western Europe, North America and Japan by this time. Following the announcement, there is unprecedented global solidarity. Despite the ongoing Cold War, the United States and the Soviet Union are united in support of the programme. In 1969, four years after Dr Baruch Blumberg discovers the hepatitis B virus, he works with microbiologist Irving Millman to develop the first hepatitis B vaccine, using a heattreated form of the virus. A plasma-derived inactivated vaccine is approved for commercial use from 1981 to 1990, and a genetically engineered (or DNA recombinant) vaccine, developed in 1986, is still in use today. n 1971 the measles vaccine (1963) is combined with recently developed vaccines against mumps (1967) and rubella (1969) into a single vaccination (MMR) by Dr Maurice Hilleman. In 1974 the Expanded Programme on Immunization (EPI, now the Essential Programme on Immunization) is established by WHO to develop immunization programmes throughout the world. The first diseases targeted by the EPI are diphtheria, measles, polio, tetanus, tuberculosis and whooping cough. In 1978 a polysaccharide vaccine that protects against 14 different strains of pneumococcal pneumonia is licensed, and in 1983 it is expanded to protect against 23 strains. Monitoring Desk/S. Raqib

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The Kabul times, Afghanistan Trustable News Agency.