DEVELOPMENT REPORT - Polio Vaccine Study

By Caty Weaver

This is the VOA Special English DEVELOPMENT REPORT.

A new study shows that an injection of the vaccine against polio increases protection against the disease among children in developing countries. This is in addition to the vaccine the children receive by mouth. The study was carried out in Oman by doctors from the United States Centers for Disease Control. Roland Sutter was the lead researcher. The New England Journal of Medicine published the study.

Doctor Sutter says the oral polio vaccine protects between sixty and seventy percent of children in poor countries. He says the same vaccine protects ninety percent of children in rich nations. Doctor Sutter says children in poor countries are given more of the oral vaccine than children in rich nations. This is done to try to reduce the difference in protection rates.

T. Jacob John of the Christian Medical College in Vellore, India has been studying the difference between polio protection rates in poor and rich countries for twenty years. He says scientists think the differences may be linked to environmental issues.

For example, industrial nations have better water and waste systems. These provide people with cleaner living conditions. But, Doctor John says researchers do know the exact link between living conditions and protection against polio.

The Oman study involved more than one-thousand babies who were nine months old. All of them already had received five doses of the polio vaccine by mouth. Doctor Sutter says blood tests showed that about eighty-eight percent of the babies were protected against the most common kind of polio.

The babies then got an injection of the vaccine. Thirty days later their blood was tested again. The results showed ninety-seven percent of the children were now protected. However, Doctor Sutter and Doctor John agree that the polio injection vaccine should not be given in all countries. They say the method should only be used in countries where polio has been completely destroyed. They say the oral vaccine alone should be continued in countries where polio remains.

This is because the oral polio vaccine contains a live virus. It is believed to better activate the body's defense system and provide protection for a longer time. Also, the oral vaccine can be given by people who do not have medical training.

This VOA Special English DEVELOPMENT REPORT was written by Caty Weaver.

Voice of America Special English