There is little question that while you are breast feeding (if you decide to breast feed) then some of your immunity to sniffles and so forth is passed on to the child. So there is a benefit in terms of the parent not having to deal with and worry about sniffles.
The question is whether, in countries with good hygiene and decent food, there is a significant difference to the child, whether in terms of survival or in terms of freedom from disabilities and serious disease.
A huge amount of pressure is put on educated and well off people to breast feed. The NCT classes imply that doing anything else is not normal. The breast feeding counsellors imply it is close to negligence. There is a government directive to support breast feeding and even the milk formula companies have to carry notices recommending it.
My observations suggest that those with less money or less education are not exposed to nearly as much of this propaganda. This may not be true, and the pressure may be on everyone. Certainly some or all women are made to feel as if not breast feeding is a failure to be a good mother.
Given my anecdotal experience it looks as if this pressure is unjustified. I have been asked to find out by one mother whether this is the case.
A preliminary search has turned up an epidemiological study from 2004 which suggests there is a relationship between SIDS (Sudden Infant Death Syndrome) and bottle feeding. After my previous experience with the SIDS research this will need a lot of careful examination.
Almost all SIDS related behaviours are tied to lower socio-economic or socio-demographic status. Where this is the case an epidemiological study must by its nature pick up a lot of potentially false signs. At least one government/FSIDs recommendation is not supported by their research, but seems like a good recommendation to make anyway. So the question comes down to is this pressure unjustified, and if so should we take the pressure off the mums?