Polio vaccines are vaccines used to prevent poliomyelitis (polio). Two types are used: an inactivated poliovirus given by injection (IPV) and a weakened poliovirus given by mouth (OPV). The World Health Organization (WHO) recommends all children be fully vaccinated against polio. The two vaccines have eliminated polio from most of the world, and reduced the number of cases reported each year from an estimated 350,000 in 1988 to 33 in 2018.The inactivated polio vaccines are very safe. Mild redness or pain may occur at the site of injection. Oral polio vaccines cause about three cases of vaccine-associated paralytic poliomyelitis per million doses given. This compares with 5,000 cases per million who are paralysed following a polio infection. Both types of vaccine are generally safe to give during pregnancy and in those who have HIV/AIDS but are otherwise well. However, the emergence of circulating vaccine-derived poliovirus (cVDPV), a form of the vaccine virus that has reverted to causing poliomyelitis, has led to the development of novel oral polio vaccine type 2 (nOPV2) which aims to make the vaccine safer and thus stop further outbreaks of cVDPV2.The first successful demonstration of a polio vaccine was by Hilary Koprowski in 1950, with a live attenuated virus which people drank. The vaccine was not approved for use in the United States, but was used successfully elsewhere. The success of an inactivated (killed) polio vaccine, developed by Jonas Salk, was announced in 1955.
As of July 2019, both girls remain healthy and the family planned to return to their home in Pakistan in 2020. History
The Moche culture of ancient Peru depicted conjoined twins in their ceramics dating back to 300 CE. Writing around 415 CE, St. Augustine of Hippo, in his book, City of God, refers to a man "double in his upper, but single in his lower half—having two heads, two chests, four hands, but one body and two feet like an ordinary man. "According to Theophanes the Confessor, a Byzantine historian of the 9th century, around 385/386 CE, "in the village of Emmaus in Palestine, a child was born perfectly normal below the navel but divided above it, so that it had two chests and two heads, each possessing the senses. One would eat and drink but the other did not eat; one would sleep but the other stayed awake. There were times when they played with each other, when both cried and hit each other. They lived for a little over two years. One died while the other lived for another four days and it, too, died. "In Arabia, the twin brothers Hashim ibn Abd Manaf and Abd Shams were born with Hashims leg attached to his twin brothers head.