1.   A moderately effective vaccine exists against some types of streptococcal pneumonia.

2.   At present, no widely approved vaccine exists for malaria.

3.   Although a vaccine exists, the United States has a limited supply that is reserved for the military.

4.   Although an effective animal vaccine for anthrax exists, scientists are always looking for a better or cheaper veterinary version, Halloran says.

5.   An old vaccine against plague exists, but it has many side effects.

6.   A vaccine against plague exists, but it is generally recommended only for people at high risk such as those working with Yersinia pestis in a laboratory.

7.   A tularemia vaccine exists but is not considered very effective.

8.   A vaccine exists, but it is in short supply.

9.   It is the only sexually transmitted disease for which a vaccine exists.

10.   Like many drugs, the vaccine existed in two versions, or isomers, chemically identical but with mirror-image molecular structures.