CONSIDERATIONS ON AGE-RELATED DIFFERENCES IN IMMUNE-RESPONSE AFTER INFLUENZA VACCINATION

In the framework of controlled field trials the humoral immune response to the surface antigens haemagglutinin and neuraminidase after one dose of inactivated influenza vaccine applicated intramuscularely was evaluated. 191 paired sera from subjects aged 18 to 40 years (n = 34), 41 to 65 years (n = 87) and over 65 years (n = 70) were tested serologically. Moreover paired sera from children aged 4 to 7 years (n = 30) and 7 to 14 years (n = 138) were included into the study. An impact of age on vaccine effectiveness was not seen in adults. 80-91 % of the aged (>65 years) vaccinees developed protective threshold titers to the vaccine components. Besides the weak immune response to the A (H1N1) component similar results were seen in children. The immune response to the A (H1N1) component depends firmly on age-related priming. An increase of neuraminidase-inhibiting antibodies was obvious in all age groups tested.