Scientists are also testing a vaccine for HIV, and they are working on vaccines against cancer.

"Vaccines are one of the greatest inventions of humankind,” said Dr. Peter Hotez, a professor at the Baylor College of Medicine.

Global vaccination programs have ended smallpox, and they are closing in on polio, a disease that used to paralyze 350,000 people each year. Because of a global immunization program, that number now stands at 20.

Pakistan and Afghanistan are the last remaining countries where the polio virus is still spreading.

Break the chains

Diseases like smallpox, polio and measles can only be transmitted from one person to another. Dr. Walter Orenstein from the Emory Vaccine Center says that’s why they can be wiped off the face of the earth.

"If you can break the chains of human to human transmission, you can eradicate the disease,” he said. "That’s how smallpox was eradicated.”

Malaria vaccine

Most of the diseases that can be prevented through vaccines are caused by viruses — think measles, mumps or chickenpox. But the most exciting news during World Immunization Week is about a vaccine against the parasite that causes malaria.

Dr. Pedro Alonso of the World Health Organization said Malawi, Ghana and Kenya will begin giving malaria vaccines to children in the coming weeks.

"This is the first vaccine against the human malaria parasite. Parasites are really complex organisms, much more so than a virus or a bacteria. And that’s why it has taken 30 years to develop this first vaccine,” he said.

Cancer and HIV

Vaccines can already protect against two types of cancer: cervical and oral cancers caused by the human papilloma virus and liver cancer caused by the hepatitis B virus. Now scientists are working to develop vaccines against breast cancer and other deadly cancers.

And then there’s HIV. HIV vaccine trials are going on in South Africa, and research is being done to develop an antibody-based HIV vaccine.

Dr. Carl Dieffenbach is a specialist in HIV at the National Institutes of Health. He says anti-AIDS drugs have already made a huge difference in controlling the epidemic.

"We put a vaccine on top of that, too, it’s not just stopping the epidemic. It’s ending the epidemic,” he said.

A world free from these diseases will be a world where more people can raise healthy children, earn a living and get out of poverty. It would be a world where not only people, but countries could prosper.

VOA