The polio vaccine, developed by Dr. Jonas Salk, is declared safe and effective.

The development of the polio vaccine is a significant milestone in medical history, representing a major victory in the fight against infectious diseases.

Background on Polio: Poliomyelitis, commonly known as polio, is an infectious disease that can cause paralysis and death. The disease primarily affects children under five years of age.

Early Research: Before the development of a vaccine, polio caused widespread fear and led to thousands of cases of paralysis each year. In the early 20th century, efforts to develop a vaccine were initially focused on producing immune sera, but these attempts were largely unsuccessful.

Jonas Salk and the Inactivated Polio Vaccine (IPV):
Jonas Salk, an American medical researcher, developed the first successful polio vaccine in the 1950s. Salk’s vaccine was based on killed (inactivated) poliovirus.
The safety and effectiveness of the vaccine were demonstrated in 1954 during one of the largest clinical trials in history, involving nearly 2 million American children.
In 1955, the vaccine was declared safe and effective, leading to a nationwide vaccination campaign.

Albert Sabin and the Oral Polio Vaccine (OPV):
Following Salk’s success, another researcher, Albert Sabin, developed an oral polio vaccine (OPV) which was easier to administer and distribute.
Sabin’s vaccine used a weakened but live version of the virus, which could provide immunization without causing the disease itself.
This vaccine was tested in the Soviet Union and was introduced in the U.S. in the early 1960s.

Impact and Eradication Efforts:
The widespread use of both Salk’s and Sabin’s vaccines led to a dramatic decrease in polio cases worldwide.
In 1988, the World Health Assembly launched the Global Polio Eradication Initiative, which has reduced polio worldwide by 99% since its inception.

Contemporary Challenges:
While polio has been eliminated in most of the world, it still poses challenges in a few countries where the virus remains endemic.
Ongoing efforts to maintain high immunization rates are crucial to prevent the re-emergence of the disease in areas where it has been eradicated.

The development of the polio vaccine not only curtailed a major health crisis but also demonstrated the potential of vaccines to control infectious diseases, shaping public health policy and research priorities in subsequent decades.

The polio vaccine, developed by Dr. Jonas Salk, is declared safe and effective.

Jonas Salk was an American medical researcher and virologist who is best known for developing the first effective and safe polio vaccine. He was born in New York City in 1914 and graduated from the City College of New York before earning his medical degree at New York University.

In the early 1950s, Salk led a team of researchers at the University of Pittsburgh to develop a vaccine for polio, a debilitating and often deadly disease that was a major public health concern at the time. In 1955, Salk’s team announced that they had successfully developed a vaccine that was safe and effective in preventing polio.

Salk’s polio vaccine was a major breakthrough in the fight against the disease and helped to significantly reduce the number of polio cases in the United States and around the world. He became a national hero and was awarded numerous honors and awards for his work, including the Presidential Medal of Freedom.

After his success with the polio vaccine, Salk continued to work on medical research and became a leading figure in the field of immunology. He died in 1995 at the age of 80.

A suicide bomber blows herself up at the entrance to Jerusalem’s Mahane Yehuda Market, killing seven people and wounding 104.

The polio vaccine, developed by Dr. Jonas Salk, is declared safe and effective.

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Harold Washington is elected as the first black mayor of Chicago.

Harold Lee Washington, April 15, 1922 – November 25, 1987 was an American lawyer and politician who was the 51st Mayor of Chicago. Washington became the first African–American to be elected as the city’s mayor in February 1983. He served as mayor from April 29, 1983 until his death on November 25, 1987. Earlier, he was a member of the U.S. House of Representatives from 1981 to 1983, representing Illinois’ first district. Washington had previously served in the Illinois State Senate and the Illinois House of Representatives from 1965 until 1976.

Washington was born in Chicago, and raised in the Bronzeville neighborhood. After graduating from Roosevelt University and Northwestern University School of Law, he became involved in local 3rd Ward politics under future Congressman Ralph Metcalfe.

The earliest known ancestor of Harold Lee Washington, Isam/Isham Washington, was born a slave in 1832 in North Carolina. In 1864 he enlisted in the 8th United States Colored Heavy Artillery, Company L, in Paducah, Kentucky. Following his discharge in 1866, he began farming with his wife Rebecca Neal in Ballard County, Kentucky. Among their six children was Isam/Isom McDaniel Washington, who was born in 1875. In 1896, Mack Washington had married Arbella Weeks of Massac County, who had been born in Mississippi in 1878. In 1897, their first son, Roy L. Washington, father of Mayor Washington was born in Ballard County, Kentucky. In 1903, shortly after both families moved to Massac County, Illinois, the elder Washington died. After farming for a time, Mack Washington became a minister in the African Methodist Episcopal Church, serving numerous churches in Illinois until the death of his wife in 1952. Reverend I.M.D. Washington died in 1953.

Harold Lee Washington was born on April 15, 1922 at Cook County Hospital in Chicago, Illinois, to Roy and Bertha Washington. While still in high school in Lawrenceville, Illinois, Roy met Bertha from nearby Carrier Mills and the two married in 1916 in Harrisburg, Illinois. Their first son, Roy Jr., was born in Carrier Mills before the family moved to Chicago where Roy enrolled in Kent College of Law. A lawyer, he became one of the first black precinct captains in the city, and a Methodist minister. In 1918, daughter Geneva was born and second son Edward was born in 1920. Bertha left the family, possibly to seek her fortune as a singer, and the couple divorced in 1928. Bertha remarried and had seven more children including Ramon Price, who was an artist and eventually became chief curator of The DuSable Museum of African American History. Harold Washington grew up in Bronzeville, a Chicago neighborhood that was the center of black culture for the entire Midwest in the early and middle 20th century. Edward and Harold stayed with their father while Roy Jr and Geneva were cared by grandparents. After attending St Benedict the Moor Boarding School in Milwaukee from 1928 to 1932, Washington attended DuSable High School, then a newly established racially segregated public high school, and was a member of its first graduating class. In a 1939 citywide track meet, Washington placed first in the 110 meter high hurdles event, and second in the 220 meter low hurdles event. Between his junior and senior year of high school, Washington dropped out, claiming that he no longer felt challenged by the coursework. He worked at a meat-packing plant for a time before his father helped him get a job at the U.S. Treasury branch in the city. There he met Nancy Dorothy Finch, whom he married soon after; Washington was 19 years old and Dorothy was 17 years old. Seven months later, the U.S. was drawn into World War II with the bombing of Pearl Harbor by the Japanese on Sunday, December 7, 1941.

Soldiers marching on the Broughton Suspension Bridge in Manchester, England result in it collapsing.

On 12 April 1831, the 60th Rifle Corps carried out an exercise on Kirsal Moor under the command of Lieutenant Percy Slingsby Fitzgerald, the son of John Fitzgerald, Member of Parliament and brother of the poet Edward FitzGerald. As a detachment of 74 men returned to barracks in Salford by way of the bridge, the soldiers, who were marching four abreast, felt it begin to vibrate in time with their footsteps. Finding the vibration a pleasant sensation some of them started to whistle a marching tune, and to “humour it by the manner in which they stepped”, causing the bridge to vibrate even more. The head of the column had almost reached the Pendleton side when they heard “a sound resembling an irregular discharge of firearms”. Immediately, one of the iron columns supporting the suspension chains on the Broughton side of the river fell towards the bridge, carrying with it a large stone from the pier to which it had been bolted. The corner of the bridge, no longer supported, then fell 16 or 18 feet into the river, throwing about 40 of the soldiers into the water or against the chains. As the river was low and the water only about two feet deep at that point none of the men were killed, but 20 were injured, including six who suffered severe injuries including broken arms and legs, severe bruising, and contusions to the head.

An investigation found that a bolt in one of the stay-chains had snapped at the point where it was attached to the masonry of the ground anchor. There was criticism of the construction method used, as the attachment to the ground anchor relied on one bolt rather than two, and the bolt was found to have been badly forged. A number of other bolts were also bent but had not broken. It emerged that three years previously the distinguished Engineer, Eaton Hodgkinson FRS, had expressed some doubt about the strength of the stay chains compared with that of the suspension chains. He had said that they should be rigorously tested, but they were not. It also came to light that some time before the accident one of the cross bolts had started to bend and crack, although it was believed to have been replaced by the time of the accident. The conclusion was that, although the vibration caused by the marching had precipitated the bolt’s failure, it would have happened anyway.

The Union Flag is adopted as the flag for use on the English and Scottish ships.

Terry Fox begins his “Marathon of Hope”.

Soldiers who were marching on the Broughton Suspension Bridge in Manchester, England cause it to collapse.