Visa and vaccinations – when do I need them?
Visa requirements all depends on your nationality, length of stay, purpose of trip, background and more. So always check in good time with your Ministry of Foreign Affairs or the embassies of the countries you are visiting.
Vaccinations and other precautions can vary a lot and situations can change rapidly.
Check the requirements in good time (several months before departure) so you know what you need and what is recommended. Especially you should note that some vaccinations and pills have to be taken over a longer period.
Also check shortly before you leave if the situation has changed.
Do I need a visa if I only change flights (transit)?
In most cases a transit visa will not be needed, but there are some exceptions to this rule. Should you for instance have a ticket which involves a flight change in the USA you will need to apply for an American 'travel permit' (ESTA).
So it is highly recommend you always check with all countries involved in your itinerary for exact rules for your nationality.
Remember also to check countries where you have a 'technical stopover' which means you do not change flights where the stopover takes place but continue on the same flight you came on.
If you change airports it will no longer be considered a transit and you will have to check the applicable rules for a 'normal' visa.