Since 1979, there have been up to 10 cases of polio a year as a result of the oral polio vaccine. The oral vaccine contains a weakened, but still live virus, while the injectable vaccine contains a dead virus.
The CDC panel recommended that as of Jan. 1, 2000, children continue to get four doses of polio vaccine at the ages of:
- 2 months
- 4 months
- 12-18 months
- 4 to 6-years-old
Federal health officials began the shift towards the inactivated polio vaccine in January 1997, when they recommended shots at 2 and 4 months of age followed by two doses of oral vaccine as children got older.
Before January 1997, they recommended children receive four doses of the oral vaccine.
"Both vaccines protect the individual very well. The difference is that the oral polio vaccine is easier to administer and is better to use in an epidemic setting, which is what we had in the 1950s and 1960s," CDC spokeswoman Barbara Reynolds said.
"Now, with no epidemic polio in this country, it's perfectly legitimate to move to an inactivated polio vaccine," she said.
Phasing out the oral vaccine reduced the number of vaccine-associated polio cases to four in 1997 and one in 1998, the agency said.
In its 8-1 vote Thursday, the committee said that the oral polio vaccine could still be used, but only in special circumstances.
The CDC said that the oral vaccine is more effective in protecting against epidemics, but it said the risk of a polio epidemic in the U.S. was so small, it was outweighed by the risk of illnesses from the vaccine.
Health officials said that all children still need to be vaccinated for polio until the illness is eradicated worldwide.
The CDC said that if polio vaccinations were stopped in the U.S., millions of children would become susceptible within a year. Since wild polio infection still occurs in many parts of the world, the virus could be imported and cause a U.S. epidemic, it said.
In effect, that means the oral vaccine probably will be eliminated in the U.S., Dr. Senay says.