Officially, people travelling to Nepal do not require any vaccinations, but is it advisable to take some precautions, especially if you are travelling off the beaten track. Vaccinations you should consider for a trip to Nepal are:
• Diptheria and tetanus
• Hepatitus A
• Japanese B Encephalitis
• Meningococcal Meningitis
• Yellow fever
Travelers entering Nepal from a country infected with yellow fever need to be vaccinated before entering Nepal.
Make sure you plan ahead for any vaccinations required as some require more than one injection in order to be effective. It is advisable to speak to your doctor about any vaccinations at least six weeks before your departure. Once you have had your vaccinations as for an International Health Certificate from your doctor.
Kathmandu does got a lot of negative coverage in the media, but as long as you stick to the tourist areas you should be safe. It is advisable to stay aware of any strikes, marches or demonstrations and stay well clear of them as they can turn violent.
If you are trekking make sure you are aware of the symptoms of altitude sickness and be sensible with your acclimatization.