Jan 10 2008 lecture 27 red font highlighted in orange highlighted in green when he said remember it indicates different page number. Movie: thurs jan 17 1-2 pm and thurs jan 24 1-2pm: one on influenza virus and 2nd one is ebola virus. Back to measles virus, it is an important virus because it still kills 1 million kids around the world per year. We have vaccine for this virus, we call it mmr mumps, measles, and rubella, these are live attenuated viruses mixed together. You get vaccinated for the 3 viruses at the same time. Measles are antigenic stable therefore it doesn"t change much. Most rna viruses have what we call antigenic drift small mutations here and there, that is normal, that how these viruses change. Antigenic stablility means they are stable for the last 50 yrs or so.