Immunization/Vaccination
Key to Prevention
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English physician Edward Jenner's observation that milkmaids stricken with a mild disease called cowpox were rarely victims of smallpox prompted him to devise the first vaccine more than 200 years ago.
One of the world's great medical successes, a modern day version of this vaccine led to the eradication of smallpox by 1980.
Since Jenner's time, advances in the sciences of virology, bacteriology, and immunology have led to an enhanced understanding of how the human body defends itself against invading microorganisms. |
 Dr. Jenner vaccinating a child in the 18th century. Jenner's work developing a vaccine for smallpox set the stage for today's research into vaccine development for diseases such as AIDS. |
Developing new vaccines
In the past 50 years, scientists in NIAID laboratories and NIAID-supported investigators at research institutions around the country have developed many new and improved vaccines against infectious diseases. Most recently, NIAID scientists developed a vaccine against rotavirus diarrhea that has the potential to reduce hospitalizations and deaths among babies, particularly in developing countries.
A number of new vaccines already have had dramatic impact on children's health, such as the new conjugate vaccines for Haemophilus influenzae type b (Hib), which causes severe bacterial meningitis in young children. Since the introduction of these Hib vaccines in the 1980s and the new conjugate vaccines in the early 1990s, Hib meningitis has been virtually eliminated in the United States and greatly reduced in other countries using the vaccine.
Vaccines designed for infants
The success of the conjugate Hib vaccines is due to a new technology developed in the 1980s. Older versions of the Hib vaccine were effective in older children, but not in babies because their immature immune systems could not recognize the outer coat of the Hib bacteria, and therefore did not stimulate protective antibodies.
By combining the outer coat with an easily recognized protein, the babies' immune systems can respond to the combined vaccine and produce the antibodies needed to protect against this disease.
Today, the tremendous advances in molecular biology will enable scientists to design other new approaches to developing vaccines against diseases that continue to plague the world's population, such as AIDS, malaria, and hepatitis C.
New Vaccines for Old and Emerging Diseases
Scientists today are working not only to develop new vaccines against diseases that still make people sick, but they also are searching for unique ways to get vaccines into people. In the 21st century, people may be able to
- eat vaccines,
- inhale them through their noses,
- or put them on their skin.
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Edible vaccines
Vaccines one can eat, called edible vaccines, are among the most unusual approaches to administering new vaccines. An NIAID-supported study of an edible potato vaccine proved successful in demonstrating that such a vaccine could stimulate an immune response. By eating genetically engineered raw potatoes containing a piece of a type of E. coli, the volunteers developed antibodies against the bacteria. |
 An edible vaccine Scientists are able to grow potato plants that contain the gene of a disease-causing microbe. Eating the potato stimulates the immune system just as a vaccine would. |
Vaccines in a nasal spray
Another NIAID-supported study demonstrated that a flu vaccine, administered as a nasal spray, was effective in preventing flu in children as well as flu-related ear infections.
 A new way to get a flu vaccine This little boy is receiving a cold-adapted influenza vaccine by nasal spray. New vaccines like this are successfully preventing culture- confirmed influenza in nearly all children who receive them. |
This new vaccine was developed by NIAID scientists and grantees by constructing a vaccine containing a weakened flu virus that does not grow at the warmer temperatures of the lungs.
Because it grows only in the cooler areas of the nasal passages, it can make a person immune to flu without causing disease. |
Maternal immunization is a strategy that might enable pregnant women to be vaccinated against certain diseases and pass protection to their newborns. Scientists are working to develop and test vaccines for pregnant women that would protect their babies against group B streptococcus and respiratory syncytial virus, both of which can cause severe illness in infants.
DNA vaccine
Even conventionally administered vaccines may require novel approaches to their design to combat organisms such as the human immunodeficiency virus (HIV), which causes AIDS, and the malaria parasite.
One new type of experimental DNA vaccine for HIV/AIDS is made from the genetic material of HIV itself. Genes coding for viral proteins of HIV are injected directly into the body. This enables the bodys to produce the viral proteins, which then stimulate the immune system to produce antibodies against HIV. Several DNA vaccines for HIV/AIDS and other diseases are already under development.
Malaria vaccines
A new approach to malaria is to develop a vaccine that prevents transmission of the malaria parasite from one infected person to another person. This type of vaccine would be given to people already infected with the parasite--not to protect them from illness but to prevent the parasite from infecting someone else.
After a mosquito bites a person whose blood contains the malaria parasite, the mosquito normally transmits the parasite to someone else when it next feeds. But this vaccine would block the sexual development of the parasite in the mosquito, so that the parasite could not cause malaria in the next person bitten by the mosquito.
New technologies such as these are providing more and more innovative ways to make vaccines that will improve health in the 21st century.
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IMAGE & INFO CREDITS
Dr. Jenner: NLM/NIH
Edible vaccine chart: Boyce Thompson Institute for Plant Research
Nasal Flu vaccine: Aviron
Dr. Jenner: NLM/NIH
Edible vaccine chart: Boyce Thompson Institute for Plant Research
Nasal Flu vaccine: Aviron