Covid vaccination for Breastfeeding Mummies

My cousin took it as she's a doc. She stopped breastfeeding for a week but continued pumping. Saw a dip in her supply even tho she pumped even more than usual. She used to be an oversupplier but now can't keep as much even aft taking milk boosting supplements frm Legendairy Milk. For her, the vaccine didnt really give much physical effects as she did not get fever or aches but instead it causes her milk supply to go down. But lucky for her tt her baby is alr 10 mths so don't really rely on milk as much as before and she has her excess milk stash frm a few mths ago. I think different ppl has different effects as her colleague did not have any drop in supply at all.