字幕列表 影片播放 列印英文字幕 [MUSIC PLAYING] The first half of the 20th century brought repeated outbreaks of poliomyelitis, more commonly known as polio. It paralyzed tens of thousands worldwide and was highly prevalent in children. No cure existed, so the only real hope was for a vaccine. By the end of the 20th century, instances of the disease had declined exponentially. Today, the story of how the vaccine was developed, tested, and distributed can offer numerous insights into how pandemics may be combated. Today, we're going to take a look at what happened after the polio vaccine was developed. But before we get started, be sure to subscribe to the Weird History channel and let us know in the comments below what other medical topics you would like to hear about. OK, here we go. The scientific community had been working to understand the causes of polio for some time. And several attempts were made at creating a vaccine. Cases of polio in the United States finally peaked in 1952 when 60,000 children were infected. 3,000 died and thousands more were paralyzed. That same year, Dr. Jonas Salk conducted the first successful human trials of a vaccine he and his team had developed by building on the work of previous scientists. In 1953, Salk showed the vaccine to his colleagues. And in a nationwide address made on the CBS Radio Network on March 26, 1953, Salk cautiously announced his results to the world. The scientist reported that the amount of antibody introduced by vaccination compares favorably with that which develops after natural infection. Salk stated that the results gave cause for optimism but warned that the objective had not yet been accomplished. Shortly after the announcement, Salk demonstrated his confidence in the vaccine by administering it to himself, his wife, and their children. And spoiler alert. They were all good. After Salk informed the immunization committee of the National Foundation for Infantile Paralysis, or NFIP, of his results, calls were made for field trials. A methodology which involved one observed control trial and a separate placebo-controlled trial was agreed upon. And groups from the United States, Canada, and Finland were selected for participation. More than a million first, second, and third graders were given the vaccine for the observed control trial. And another 750,000 were involved in the placebo-controlled trial. Overall, approximately 1.8 million children were involved. The first to receive the vaccine injection as part of the trial was a boy named Randall Kerr from McLean, Virginia, who enthusiastically proclaimed, "I could hardly feel it." Salk's research, which was carried out at the University of Pittsburgh, was funded by the NFIP. Founded by President Franklin Delano Roosevelt in 1938, the organization aimed to bring together researchers, educators, and volunteers to combat polio, which FDR himself had contracted at the age of 39. The first call for donations went out over the radio in January of 1938 when comedian Eddie Cantor told the public that the March of Dimes will enable all persons, even the children, to show our president that they are with him in this battle against this disease. He added nearly everyone can send in a dime or several dimes. It worked and the White House quickly received nearly 2.7 million dimes. The program eventually paid for trials that took place in 211 countries and 44 states at a cost of nearly $8 million. It was so successful, in 1979, the NFIP would formally adopt the name March of Dimes. [MUSIC PLAYING] In 1955, the NFIP released the results of the trials which showed that Salk's vaccine was 80% to 90% effective. Salk for his part didn't deny that the vaccine wasn't perfect. But he did insist that work to improve it was continuing. He held out hope that further research would lead to a 100% effectiveness rate against paralysis. Future improvements not withstanding, the trials convinced the government to license the vaccine to several American pharmaceutical companies. And during the spring of 1955, nearly 5 million children across the US received an inoculation. During an interview with legendary newsman Edward R. Murrow, Salk was asked about whether he had patented the vaccine. The scientist famously responded with a question of his own, asking, could you patent the sun? While the NFIP did explore the idea of patenting the vaccine, they eventually concluded they didn't meet the requirements. Salk himself never sought a patent, which brought him great praise for what has widely been viewed as a selfless act of philanthropy. [MUSIC PLAYING] In 1955, five separate labs from across the United States made over four million doses of the vaccine. But despite this incredible action, there were still newly reported cases of paralytic polio. And scientists were getting concerned. An investigation showed that many of the new cases had appeared in people who received a vaccination from a manufacturer called Cutter Laboratories. And in May of 1955, Surgeon General Leonard Sheele suspended all vaccinations in the US. While vaccines made by Cutter were removed from the market, approximately 400,000 children had already been given the faulty doses. Of those, 250 developed polio, which was then spread to as many as 220,000 other people. At least 10 died. The incident led the National Institutes of Health and Public Health Services to issue safety and testing standards for the vaccine later the same year. Vaccinations resumed in the fall of 1955. But the faulty Cutter Labs vaccines had left the public skeptical of Salk's formula. It was at about this time that people turned to the work of Dr. Albert Sabin. Sabin had created an oral vaccine that used an attenuated but live strain of polio whereas Salk's injected vaccine used a killed virus. While the NFIP financed Sabin's early research, it wouldn't support large field trials in the United States. So the doctor looked elsewhere. In 1957, the Soviet Union granted Sabin permission to conduct his field trials. Over the next two years, 4.5 million people in the Soviet Union as well as Malaya, Mexico, Poland, and Czechoslovakia would take his oral vaccine. The trial showed Sabin's vaccine was safe and effective. Once the news got out, medical professionals around the world began to debate the pros and cons of Salk's injected vaccine versus Sabin's oral vaccine. Once the vaccine was widely available, nations around the globe began implementing their own vaccination programs. The United Kingdom initiated their program in 1956 by offering the injected vaccine to all children under 10 years of age. Over time, more and more people became eligible. And by 1962, after switching to the oral vaccine, the UK had vaccinated most people under the age of 26. Vaccinations began in Canada and Denmark in 1955. Sweden and the Netherlands got started in 1957. And West Germany, who had initially tried a natural immunity approach, began the following year. By the end of the '50s, over 90 countries were vaccinating their citizenry. [MUSIC PLAYING] Starting with the introduction of the Salk vaccine in the 1950s, the number of polio cases in the United States declined consistently. By the 1960s, instances of the disease numbered in the hundreds. And by the 1970s, there were in double digits. Studies indicated that many of these later cases arose in individuals who hadn't been vaccinated or hadn't completed their vaccination. In 1979, the United States saw its last cases of wild polio virus which presented in certain under-vaccinated religious communities. Once these cases were dealt with, the US declared itself free of polio. While the disease has occasionally been brought into the country through international travel, this declaration has proven mostly correct. The United States is not the only country to have eliminated polio thanks to large scale immunization programs. The UK saw its last naturally occurring cases of the disease in 1984. And Canada declared victory in 1994. Eradicating polio worldwide was a noble goal, but it wasn't entirely clear it could actually be done. Many countries around the world were at war, which made mass vaccination difficult, if not impossible. To help accomplish the goal, various international aid agencies worked to broker what they called days of tranquility. These periods would bring cease fires that could serve as national immunization days where large numbers of people could receive a vaccine. The Civil War in El Salvador was halted for three Sundays in 1985 for such mass vaccinations. During that time, 2/3 of the nation's children were immunized. Another national immunization day took place in Lebanon in 1987. Arranged by the United Nations Children's Fund or UNICEF, the vaccine was made available in certain so-called corridors of peace. These wouldn't be the last. From 1990 to 2000, days of tranquility allowed mass immunizations across Eastern Europe, Africa, the Middle East, Southeast Asia, South America, and Central America. In 1985, Rotary International initiated its PolioPlus campaign. According to the organization, less than half of the world's children had been immunized against polio at the time. However, by 1992, more than 80% had received the vaccine. To raise funds for distributing the vaccine, Rotary worked alongside other groups like UNICEF, the World Health Organization, and the Pan American Health Organization. And in 1988, they lobbied the World Health Assembly itself for a resolution to eradicate polio. Rotary International subsequently became a founding member of the Global Polio Eradication Initiative. In the interests of combating polio, the GPEI, as it's known, brings national governments together with private actors like the Centers for Disease Control, the Bill and Melinda Gates Foundation, and Gavi, The Vaccine Alliance. Despite the fact that the World Health Organization set the year 2000 as their goal for eradicating polio, the fight continues to this very day. Wild polio was eradicated in the Americas in 1994, the Western Pacific in 2000, and Europe in 2020. However, According to the GPEI, the epidemic still remains in some parts of the world. On the upside, in 2019, the WHO confirm the eradication of type III polio virus. Type II had been defeated in 2015 though several vaccine-derived cases have arisen in Nigeria since that time. Type I and vaccine-derived cases of type II, however, remain widespread in both Afghanistan and Pakistan. Many of these vaccine-derived cases occurred because the oral vaccine, which became more widely used due to its easy administration and low cost, contains a live virus. This means that there's a small chance of contracting the virus from the oral vaccine itself. How small a chance? The numbers tell us it's about 1 out of every 2.5 million doses. For these reasons, the oral vaccine is no longer used. And as of 2019, the injected vaccine is what is employed in every country. Vaccines will be required until all three strains of polio have been completely eliminated. The GPEI continues to work toward that goal. Until that mission is fulfilled, the organization will continue to work towards safer vaccines and wider inoculation. So what do you think? How long would a vaccine take to implement in our current predicament? Let us know in the comments below. And while you're at it, check out some of these other videos from our Weird History.
B2 中高級 美國腔 脊髓灰质炎疫苗开发后发生了什么(What Happened After Polio Vaccine Was Developed) 8 1 joey joey 發佈於 2021 年 05 月 23 日 更多分享 分享 收藏 回報 影片單字