What is the consensus on the necessity of vaccinations for polio, typhoid, meningitis, hep A and malaria pills? What about prophylactic use of anti biotic for TDiarreah?
Typhoid and malaria is recommended esp if you plan to go trekking or wildlife watching in forest reserves. Though it'll be cold (and hence lower chances of infections) in northern India, it also depends on where you are going. If you are visiting Varanasi, Haridwar or Mathura and are likely to feast on the local food, get vaccinated against infections. Book good hotels and try to choose one that provides good food.
Polio is a must and in India is compulsorily administered to all children below the age of 5. almost 5 years ago