Why did Sabin create an oral vaccine?    - Oral vaccine are always more effective than injected vaccines.    - He thought it would be easier to take.    - It mimics the normal virus entry into the body.

What are some ways that viruses have evaded our immune system? Include source used. Thank you

What type of vaccine is the Moderna vaccine? Oan adenovirus vaccine an inactivated virus vaccine a self-replicating RNA vaccine a protein vaccine a MRNA vaccine

answer doesn't have to be long i just need an explanation, thank you!   The whole world right now is concerned (or they should be) about the appearance of new variants of SARS-CoV-2. Among other things, these variant viruses have mutations that change the amino acid sequence of the spike protein on the virus surface. While this is concerning, I would like to propose that there is a limit to how far these mutations can change the spike protein. Why can't there be an endless number of new mutations of this viral protein? How would these amino acid changes affect how the virus works?