A study published by scientists from the National Institutes of Health provides additional evidence that persons who received the 1976 vaccine may have immunity from pandeminc H1N1 (pH1N1).
Researchers evaulated immune responses in mice after exposing them to several H1N1 viruses (1918, 1940, 1976 and 2009) and found that prior infection with a 1976 H1N1 virus provided complete protection against pH1N1. Mice infected with either 2009 or 1940 seasonal H1N1 viruses showed partial protection from pH1N1.
More detail via Research sheds new perspective on much-maligned 1976 swine flu (H1N1) vaccination campaign – influenza monitor.