I have been hearing that we have never eliminated a respiratory virus as an argument against the constant moving of the goalpost for COVID-19 measures. Since I try not to take statements like these as truth without verifying them, I thought this community would be a good one to present the claim to.
Are you aware of a respiratory virus that has been eliminated?
And as a related question, do you believe it is reasonable and achievable to attempt to eliminate any respiratory virus?
Hey, I like the solid scientific questions! And since this is virology, I'd love to weigh in.
To the first question, it depends on what you classify as a respiratory virus. I'd hesitate to call smallpox a respiratory virus, and technically that is the only virus that has ever been truly eliminated from the population. Poliovirus might be considered respiratory because it affects respiration, but I'd say it's a nervous system disease that affects respiration by proxy. To Oro's point, SARS and MERS are practically eliminated, but the issue there is that they come from animal reservoirs and any vaccines that have been produced came too late to be all that useful. The better examples I can think of regarding near-eliminations of viral diseases (at least in certain populations or even countries) are things like Rubella and Measles, which are clear examples of respiratory viruses that are clearly addressed by vaccines and, when vaccination is widespread enough, have been eliminated from those vaccinated populations.
But to the point of your second question, part of what's necessary to consider is the relative mutagenesis of each virus. Many viruses are highly mutagenic and often escape immune responses. Those are your Influenzas (which tend to modify their surface proteins quite a bit) and your cold viruses (which are often composed of multiple individual viruses and can get really complicated). There's also other considerations such as the route of infection. Many respiratory infections get into the lungs where the immune response is strong and, if it's directed appropriately, effective. However, many others (often cold viruses) don't actually go that far into the body, staying in the upper respiratory tract. Those viruses tend to elicit strong immune responses for the purpose of spreading, so even if you do vaccinate against them, the effectiveness of said vaccination against getting sick is minimal and against spreading the virus is almost absent.
Long story short, it's muddy. Some respiratory viruses definitely can be eliminated with existing techniques. Most likely can't.