From what most polyclinics and paediatricians have advised, it is okay for LO to have vaccinations if they have slight flu/cough - as long as it's not viral (many different causes) or having fever as those might affect their immune system's ability to formulate a plan against what you've vaccinated against!
Whatever it is, remember that vaccinations are NOT 100% guaranteed that you won't get whatever you vaccinated against - vaccines are meant as "training" for the body to learn how to fight against it if it ever contracts the real thing.
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