... tend to mutate at different rates and in different ways that make it more or less difficult to create an effective vaccine.
The vaccines they create every year for seasonal flu strains influenza B and influenza A(H1N1) are generally pretty effective in reducing chances of contracting. The vaccines are a lot less effective against Influenza A(H3N2) because, as I understood it, that strain mutates more rapidly.
I looked around a little more and it sounds likes it's more complicated than that. It sounds like it also has to do with the type of changes. (Excerpt from CDC explanation below).
In any case, I don't think anyone can predict how effective a vaccine developed for COVID 19 would be until they know a lot more about it's "behavior" (for lack of a better word).
Doing all we can now to stop COVID 19 from becoming a new, widespread, seasonal illness is paramount. I don't think we can count on a vaccine to "save us" down the line.
From https://www.cdc.gov/flu/vaccines-work/vaccineeffect.htm
Growth in eggs is part of the production process for most seasonal flu vaccines. While all influenza viruses undergo changes when they are grown in eggs, changes in influenza A(H3N2) viruses tend to be more likely to result in antigenic changes compared with changes in other influenza viruses. These so-called “egg-adapted changes” are present in vaccine viruses recommended for use in vaccine production and may reduce their potential effectiveness against circulating influenza viruses. Other vaccine production technologies, e.g., cell-based vaccine production or recombinant flu vaccines, circumvent this shortcoming associated with the use of egg-based candidate vaccine viruses in egg-based production technology, but CDC also is using advanced molecular techniques to try to get around this short-coming.
= new reply since forum marked as read