Aspiration before the covid injection was specifically not recommended.
I don’t know who issued that policy...it’s not in any of the covid injection literature. All IM vaccinations need to be aspirated...covid or otherwise. Even if it was Pfizer themselves saying it you always aspirate an IM injection with a slight tug. It’s not gointo harm the tissues or the mixtures. A mild tug will tell you if it hit a vessel...it needn’t be a hard pull.
Aspirate before you vaccinate...that was our NURSING school’s golden rule!
Otherwise any vaccination or injectate not designed for the blood stream that hits the bloodstream can cause major issues, blood clots, and death...covid, flu shots guardisil, tetnus shots...ect!