What of the following can be used as vaccines?
All of the above
Vaccine, contains weakened or dead versions of a pathogen that mimic the infection caused by the live pathogen and prepares the body for an effective immune response. Vaccines can be created in several ways. Whole viruses killed by heat or chemicals in such a way that they are just effective to elicit an immune response. Sometimes the viruses are attenuated by modifying the viral DNA. Some fragments or proteins from the virus that are antigenic having the capability to trigger immune response can be isolated and used as vaccines.