alleryStart learning →What is the particular danger of giving a live attenuated viral vaccine?
AIt cannot raise protective immunity
BIt may mutate back to a harmful form
CIt always needs a booster each year
DIt kills every host cell that it enters
Answer & Solution
Correct answer: B. It may mutate back to a harmful form
1. Live vaccines are usually more effective than killed vaccines.
2. They carry a low but real danger that the virus reverts to its disease-causing form by back mutation.
3. A back mutation lets the vaccine virus readapt to the host and cause disease again, which can then spread.
4. Exactly that happened in Nigeria in 2007, where mutations in a polio vaccine led to an epidemic of polio.
5. Raising protective immunity is what a live vaccine does well, so the first option states the opposite.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 21 "Viruses", section 21.3 Prevention and Treatment of Viral Infections_
Keep practising Virology
Browse all Virology questions for DHA Medical Licensing Exam, or explore more Microbiology topics.
Related questions
Spot the false virology claimName the virology termEnveloped or naked?Sort viruses by genome chemistryRun the virus replication cycleWhat does a viroid produce inside the plant cell it has infected?Viroids are best described as which kind of infectious particle?Kuru spread among people in Papua New Guinea through which practice?