Hi mommy! According to what a pediatrician said in a forum I attended, ang immunization/vaccine is essentially something injected sa body para gumaya ng infection, that way, tine-train niya ang natural defenses ng body mo! :) This is why kadalasan after immunization, nagkakalagnat tayo or ang kids natin, or sometimes colds. Para siyang exam na need maipasa ng bodily defenses natin para kapag may real viral infections na, alam na ng body natin ang gagawin :) If symptoms persist longer than usual, consult a doctor po.