填空题

Malaria is a very serious disease that kills more children under the age of five than any other disease. People get malaria when they are bitten by 1 called mosquitoes. The mosquitoes 2 which enter a person"s blood and cause malaria.
Carter Dibbs is an American doctor who works on the 3 for the United States Agency for International Development. Doctor Dibbs says the parasite that causes malaria is much 4 , such as the virus that causes polio. He says the malaria parasite 5 so that it is more difficult to make a vaccine that is safe and will 6 .
Malaria vaccines are now 7 in Burkina Faso and Mall. Vaccines are being tested on children in Mozambique and Mall. Many organizations are 8 . They include U, S. A. I. D, the American military, American health organizations, 9 .
To make sure that a vaccine will 10 , it must be tested on many people in many different places. Doctor Dibbs says the people who join the vaccine tests are as important to 11 as the scientists.
People are told about the tests during public meetings 12 . Doctor Dibbs says people should 13 that could happen to their bodies if they take the medicine that is being tested. Adults or parents of children must agree to the vaccine test.
Adults receive 14 the vaccine medicine. The children receive either the malaria vaccine or a different medicine that 15 a different disease.
Then health care workers 16 to see if they show any signs of malaria. The results of the tests must be compared to people who have not 17 .
The vaccine is successful if 18 who receive it do not show any signs of malaria for one year.
Then the United States government will be asked to 19 . However, it could still take another five years before 20 to give to all the children in Africa and around the world.