HC Deb 24 April 1961 vol 639 c8W
Mrs. Butler

asked the Minister of Health if he will state the longevity of protection of diphtheria immunisation.

Miss Pitt

This varies from person to person. In general, a person who has concluded a primary course or received a reinforcing inoculation within the previous five years can be regarded as well protected and some degree of protection is likely to persist for a longer period.