Cdc fda history with vaccines revealed

The work involved exposing animals to small doses of rabies, much like the variolation had been done in the past. This did not work, however. The rabies virus was too infectious, too virulent. As a result, Pasteur approached the problem differently: weaken the infectious agent somehow before giving it to a person. One version of smallpox variolation involved drying the material extracted from smallpox lesions before giving it to someone.

It was believed the drying caused the material to be less virulent, so. By this time, it was understood that the virus attacked the central nervous system of infected animals. Even if the virus could not be seen, the damage was visible. Pasteur took the dried brain and spinal cord from one rabbit, and gave it to another. He would wait for that rabbit to develop rabies, euthanize it, and repeat the process with a third, then a fourth, etc.

Late down the chain, rabbits exposed to the dried brain and spinal cord were not getting sick. Furthermore, they were resisting any attempts at infection through fresh specimens of saliva from rabid animals. Before going public with his findings, Louis Pasteur -- like Edward Jenner -- took a gamble and exposed human subjects to the dried material in reverse.

He started with dried brain and spinal cord from the last rabbit to be inoculated, and worked toward the material from the first rabbit, delivering stronger and stronger doses of the rabies virus. The most well-known human subject was , a young man bitten by a rabid animal. To save Joseph's life, physicians allowed Pasteur to practice his procedure on Joseph.

After all, without a cure, Joseph would likely suffer a painful death from rabies. Attempting something was better than nothing. After the expected incubation period of rabies of about 21 days, Joseph did not develop any signs or symptoms of the disease. Pasteur's vaccine was a success. The next leap in vaccination technology had occurred.

Scientists used an analogue to the infectious agent -- cowpox for smallpox -- to use the infectious agent in a less virulent "attenuated" way. Other vaccines developed at, or in collaboration with, the Pasteur Institute in Paris, France, were based on the same principle of weakening the pathogen before giving it as an inoculation.

Later in the s, scientists studying the immune response of humans and other animals discovered antibodies. These proteins were created some time after infection, and they would bind to the pathogen and inactivate it. That "some time after infection" was critical, however. Without antibodies, the person could develop the disease and perish.

Scientists then worked on safe ways to create those antibodies in large batches and give them to people as a sort of immune patch, while people developed their own antibodies. Thus was born the era of anti-toxins. While not true vaccinations, anti-toxins were created when a toxin from tetanus or was given to a large mammal, like a horse. The mammal would develop antibodies against the toxin, and the antibodies were harvested, purified, and given to people showing signs of the disease.

In , contamination of one such anti-toxin with actual tetanus toxin led to several injuries. It was the first step toward regulation of medicines and therapies, something we still see today. Later, in the s, scientists discovered that an antitoxin combined with a toxin would inactivate the toxin, but leave it intact enough for the human immune system to react against it.

Antitoxin-toxin vaccines for diphtheria and tetanus were developed. However, a problem persists in a large segment of the population receiving antitoxin alone or in combination with a toxin. They were developing an allergic reaction to the proteins from the animals used to create the antitoxin. To solve this problem, scientists found a way to inactivate the toxin before giving it as a vaccine.

The age of toxoid vaccines was born, giving us such vaccines as the diphtheria and tetanus vaccines. Protection against those diseases became safer after not having to rely on large mammals to produce them. In the s, scientists developed the electron microscope. Unlike traditional light microscopes, electrons were used as the "probe" to visualize structures smaller than those seen under light microscopes.

This brought about a revolution in virology, as individual viral particles were first seen and classified according to their shapes and sizes. It was no longer necessary to wait and see what kind of infection would be caused by inoculating cell cultures or laboratory animals. Now, a specimen could be placed under an electron microscope, and the causative agent identified.

Electron microscopy led to an explosion in viral research. Samples from the Spanish Flu pandemic were analyzed, and the influenza virus was observed and classified. Document Type:. Thacker CDC Library collection. Clear All Search. Query Builder Select one Division of Healthcare Quality Promotion. Download Document. Copy Copied Save. Details: Corporate Authors:.

Vaccines are one of the greatest success stories in public health. Through use of vaccines, we have eradicated smallpox and nearly eliminated wild polio virus. The number of people who experience the devastating effects of preventable infectious diseases like measles, diphtheria, and whooping cough is at an all-time low. Content Notes:. Name as Subject:.

National Childhood Vaccine Injury Act. Stephen B. Tools Tools. Download as PDF Printable version. In other projects. Wikidata item. Chronology of most common vaccines. References [ edit ]. The History of Vaccines. Philadelphia: The College of Physicians of Philadelphia. Archived from the original on 6 June Retrieved 9 August El Siglo Med in Spanish.

L'infection bacillaire et la tuberculose chez l'homme et chez les animaux in French 2 ed. Paris: Masson et Cie. Archived from the original on 17 July