As of 1998, there is no vaccine that is effective against parrot fever.

vaccine is not effective against protozoal diseases because of complex lifecycle of protozoa and multiple strains.

A diphtheria vaccine is effective for prevention and available in a number of formulations.

Once you have had Hepatitis B there is no need for a Hepatitis B vaccine. The vaccine is only effective for those who have not had the disease, it is used to prevent a hepatitis B infection.

Hepatitis B vaccine is safe and effective on 50 percent of all patients who are vaccinated.