Phase IV trials are only undertaken after formal approval by FDA and EDA; they are not relevant in the current context. The current vaccins (including Pfizer, m

Phase IV trials are only undertaken after formal approval by FDA and EDA; they are not relevant in the current context. The current vaccins (including Pfizer, moderna which clearly use a novel mechanism for delivery) also don't have phase IV data yet. Thank God they have been approved though, they are currently clearly the way out of a pandemic that so far has claimed 3.4 million deaths. I really don't understand what you on about, sorry.