I just brought my month old baby to take HEP B vaccine jab. He has been behaving differently since. He has been drinking lesser and sleeping slightly longer. He was drinking 140ml bm, 120ml fm. Now he only drinks about 90ml bm, 80ml fm..And he hasn't pooped much as compared..Is this normal? If so, How long will he return to his normal feed & poo?

It's normal to drink less after an immunization but do try to encourage feeding during the day, keep offering fluids. With lesser intake results in lesser output naturally. For my baby the vaccine only affects her for that day and she usually resumes normal activity the next day. If baby is not drinking or suckling well do send him in for a check. Also do make sure that vaccine site is not inflamed. http://www.livestrong.com/article/111206-baby-vaccinations-side-effects/

thanks