Hello, I recently wrote a post about my baby being sick. We were all…

Hello, I recently wrote a post about my baby being sick. We were all recovered last week! And what do you think, they started to drip again. Question: how can we boost our child's immunity? What vitamins in drops can we use? What should we do so that the child doesn't get sick often? The house is ventilated, we go for walks outside, nobody gets sick at home, no one comes to visit when they have a cold, and the house is always warm.