But she said that the killed vaccine used in the monkey experiments would have to be made more potent to offer hope for humans.

They are used, however, because they give better immunity than the killed vaccine and are easier to administer.

While killed vaccines do not have this risk, they cannot generate specific killer T cell responses, and may not work at all for some diseases.

The Soviet Union had earlier developed a killed vaccine, but its side effects prevented its licensing abroad.

The killed vaccine is injected, while the live vaccine is given as a nasal spray.

The collaborative group found that when polio is eliminated in a population, they could safely switch to killed vaccine and be protected from recurrent epidemics.

"Live polio vaccine, competing with Salk's killed vaccine.

Virtually no cellular or mucosal responses are detected in animals receiving the killed vaccine or soluble protein alone.

The Salk vaccine is administered intramuscularly, and being a killed vaccine, predominantly induces systemic antibodies.

"The quick and easiest one is the killed vaccine," said Dr. Anthony S. Fauci, the director of the institute.

He prepared vaccines from these bacteria and found that frequently a marked improvement occurred in the health of the patient after treatment by injection of the appropriate killed vaccine.

Apparently, killed vaccines provide less non-specific protection, while live vaccines (measles) provide more non-specific protection from other illnesses in infants.

An inactivated vaccine (or killed vaccine) consists of virus particles which are grown in culture and then killed using a method such as heat or formaldehyde.

Because these vaccines are made with viruses that are weakened but not killed, they cannot normally be combined with the killed vaccines given earlier in life, vaccination experts said.

And MedImmune said that a small clinical trial suggested that the live vaccine provided more protection than the killed vaccine to the strain of virus that is circulating this year.

(Nearly every American child is still immunized - albeit with a killed vaccine given by injection - even though polio was virtually wiped out in the United States in the 1960's.)

The Beef CRC produced two new killed vaccines against Pasteurella and pestivirus which cause bovine respiratory disease (BRD), both firsts for Australia.

Against considerable opposition from The March of Dimes Foundation, which supported the relatively effective killed vaccine, Sabin prevailed on the Public Health Service to license his three strains of vaccine.

The rabies vaccine was initially created by Emile Roux, a French doctor and a colleague of Pasteur who had been working with a killed vaccine produced by desiccating the spinal cords of infected rabbits.