My 15-month-old has had 2 ear infections. My mom heard that children who had more soy products in their diet have fewer ear infections. Didn't know if you had heard anything about this or not.
Most ear infections happen before 2 years of age, and most happen between November and March (in the Northern Hemisphere). If your daughter has only had two by 15 months, she is probably well on her way to outgrowing them.
Of the kids who are prone to ear infections (about 1/3 of kids), allergies are the underlying cause about 1/3 of the time. Cow's milk is the most likely non-airborne culprit. Presumably, it causes inflammation of the Eustachian tubes -- the tubes that normally keep the ears clean and drained. It can also change the nature of the secretions.
So yes, some kids who have ear infections would have fewer infections if they drank soy. Perhaps soy may even promote better ear conditions in some kids who are not even allergic to cow's milk.
Breast milk, of course, is the best drink for babies to prevent ear infections.