Breastmilk gives best immunity since it contains prebiotics and HMO. That's the best to give to baby exclusively until 6 months.

Best way to increase immunity is breastfeeding. And if any issues with breastfeeding then choose Prebiotics and HMO rich FM.

यदि आपको यह उपयोगी लगता है, तो मुझे आपसे सुनना अच्छा लगेगा। इसकी समीक्षा करने में 30 सेकंड से भी कम समय लगेगा. यहाँ लिंक https://play.google.com/store/apps/details?id=app.babychakra.babychakra&gl=US है.

This is how the immunity increase naturally

Breastfeeding will help you to ensure your child's immunity increases naturally. This will allow him/her to get natural immune boosters from the milk.