<prompt> After reconstitution, the vaccine must be stored in the dark at 2-8 degree C and used within: September 20041 hour2 hours3 hours6 hours  <response>: Ans. D i.e. 6 hour Reconstituted measles vaccine loses about 50 of its potency after 1 hour at 20 degree C; it loses almost all potency after 1 hour at 37 degree C. 