Five previous vaccine campaigns and how they work



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Scientists developed vaccines less than a year after the identification of Covid-19, which reflects remarkable advances in vaccine technology. But progress in vaccine distribution is another story.

Many questions that arose in vaccine deployments decades ago are still debated today. How should local and federal authorities coordinate? Who should get vaccinated first? What should officials do in the face of resistance in communities? Should we give priority to the places most affected? Who should pay?

Some answers can be found in the successes and failures of vaccination campaigns over the past two centuries.

In 1796, after scientist Edward Jenner discovered that people with smallpox were immune to smallpox, doctors went from town to town in England, deliberately spreading cowpox by scratching infected material in the arms of people.

The deployment worked locally, but how could it be distributed to people in faraway places, such as the Americas, where smallpox had devastated populations? In 1803, the Spanish government put 22 orphans on a boat to its territories in South America. Senior physician Francisco Xavier de Balmis and his team injected two of the boys with chickenpox and then, once the chickenpox sores developed, took material from the sores and scratched him in his arms. two other boys.

By the time the team arrived in the Americas, only one boy was still infected, but that was enough. The distribution of vaccines in the Spanish territories was not systematic, but eventually members of the Spanish expedition worked with local political, religious and medical authorities to establish vaccination clinics. More than 100,000 people in Mexico received free vaccinations in 1805, according to a newspaper article, “The World’s First Vaccination Campaign,” in the Bulletin of the History of Medicine.

By the 20th century, when scientists figured out how to store and mass produce smallpox vaccine, outbreaks had generally been contained.

But an epidemic in 1947 in New York City, just before an Easter Sunday parade on a hot weekend, posed a major problem. The city’s health commissioner at the time, Israel Weinstein, called on everyone to get vaccinated, even if they were vaccinated as children. Posters across town warned, “Be sure. Be careful. To get vaccinated!”

The deployment was swift and well orchestrated. Volunteers and health professionals have visited schools to deliver vaccines to students. At the time, the public had strong confidence in the medical community, and the modern anti-vaccination movement barely existed. In less than a month, more than six million New Yorkers were vaccinated, and the city ended up recording just 12 infections and two deaths.

On April 12, 1955, the US government authorized the first polio vaccine, created by Dr. Jonas Salk, after scientists said that day that it was 80 to 90 percent effective.

Vaccines against covid19>

Answers to your questions about vaccines

While the exact order of vaccinees can vary from state to state, most will likely prioritize medical workers and residents of long-term care facilities. If you want to understand how this decision is made, this article will help you.

Life will only return to normal when society as a whole is sufficiently protected against the coronavirus. Once countries authorize a vaccine, they will only be able to immunize a few percent of their citizens at most in the first two months. The unvaccinated majority will always remain vulnerable to infection. A growing number of coronavirus vaccines show strong protection against the disease. But it is also possible for people to spread the virus without even knowing they are infected, as they show only mild symptoms, if any. Scientists do not yet know whether vaccines also block transmission of the coronavirus. So for now, even vaccinated people will have to wear masks, avoid crowds inside, etc. Once enough people are vaccinated, it will become very difficult for the coronavirus to find vulnerable people to infect. Depending on how quickly we, as a society, reach this goal, life may start to move closer to something normal by fall 2021.

Yes, but not forever. The two vaccines that will potentially be authorized this month clearly protect people against Covid-19 disease. But the clinical trials that delivered these results were not designed to determine whether vaccinated people could still spread the coronavirus without developing symptoms. It remains a possibility. We know that people naturally infected with the coronavirus can spread it without experiencing a cough or other symptoms. Researchers will study this question intensely as the vaccines are rolled out. In the meantime, even vaccinated people will have to consider themselves as possible spreaders.

The Pfizer and BioNTech vaccine is given by injection into the arm, like other typical vaccines. The injection will be no different from any you received before. Tens of thousands of people have already received the vaccines and none of them have reported serious health problems. But some of them experienced short-lived discomfort, including aches and pains and flu-like symptoms that usually last for a day. People may need to plan a day off or school after the second shot. While these experiences are not pleasant, they are a good sign: they are a result of your own immune system meeting the vaccine and building a powerful response that will provide long-lasting immunity.

No. Moderna and Pfizer vaccines use a genetic molecule to stimulate the immune system. This molecule, known as mRNA, is ultimately destroyed by the body. The mRNA is packaged in an oily bubble that can fuse with a cell, allowing the molecule to slip inside. The cell uses mRNA to make proteins from the coronavirus, which can stimulate the immune system. At any given time, each of our cells can contain hundreds of thousands of mRNA molecules, which they produce to make their own proteins. After these proteins are made, our cells shred the mRNA with special enzymes. The mRNA molecules that our cells make can only survive for a few minutes. The mRNA in vaccines is designed to resist the enzymes in the cell for a little longer, so that the cells can make additional viral proteins and elicit a stronger immune response. But mRNA can only last a few days at most before being destroyed.

The next day, The New York Times reported in a front-page headline: “Supply will be limited for time, but production will be rushed.”

State and local health officials were responsible for deployment to children, who were most at risk of contracting the disease.

“Young African American children were affected, but they were not at the top of the priority list due to the social conditions of the time,” said Dr. René F. Najera, editor of the History of Project. Vaccines at the College. doctors from Philadelphia. Noting that it was difficult for parents in working class jobs to take the time to queue up with children in clinics, Dr Najera said, “You see it again and again, the story goes. kinda repeats. “

Shortly after the deployment began, the program was suspended after learning that children had contracted polio in the arms where they had been vaccinated, rather than in the legs, which was more typical of the disease.

More than 250 cases of polio have been attributed to faulty vaccines, caused by a manufacturing error by one of the drug makers involved in the effort, California-based Cutter Laboratories, according to the Centers for Disease Control and Prevention.

The so-called Cutter incident led to stricter regulatory requirements, and vaccine deployment continued in the fall of 1955. The vaccine prevented thousands of cases of crippling diseases, saved lives, and ultimately ended. the annual threat of epidemics in the United States.

The H1N1 flu virus, which originated in Mexico, struck in the spring of 2009, not during the typical flu season.

By the end of the summer, it was clear the virus was causing fewer deaths than many strains of seasonal flu, and that some of Mexico’s early reports had been exaggerated. This was one of the main reasons many Americans avoided the flu shot when it was ready in the fall. It wasn’t just the anti-vaccination movement, although that was a factor.

The H1N1 virus was severe in children and young adults and appeared to have a disproportionate death rate in pregnant women. Because of these factors, the first groups to be vaccinated, after health workers, were those at the highest risk of complications, pregnant women and children.

The last group eligible for the vaccine were healthy people over 65, who were least likely to get it because they appeared to have resisted it.

Donald G. McNeil Jr. contribution to reports.

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