What happen if something happens and we can't get blood?

I have been wondering about this.. What if something happens like war or natural disaster happens and we can't get blood.  Can thal major technically survive without getting blood transfusion? Like does the body just reach a low HB all the time and we will be really tire but still manage?

Our friends in war zones have a terrible time getting treatment. Often, the only choice is to try to migrate to another country. True thal majors cannot live without transfusions. Transfusing intermedia patients can survive, although not in good health.