Comparison of total serum meningococcal-specific igg level in the elderly and young adults after meningococcal vaccination running head: Meningococcal vaccination in the elderly and young adults

Background: In the elderly, the immune system undergoes age-associated decline in function known as immunosenescence, which produce a progressive deterioration in the ability to fight infections and to develop immunity after vaccination. The elderly who become umrah pilgrims have a high risk of meningococcal infection. We aimed to compare total serum level of meningococcal IgG changes in the elderly and young adults before and after meningococcal MenACWYCRM197 vaccination. Methods: This study involved elderly (aged > 60) and young adult umra pilgrims in Surabaya Indonesia with a pre-post test design. MenACWY-CRM197 vaccination was done before umrah pilgrimage. Total serum meningococcal-specific IgG level was examined by ELISA before and 1 month after vaccination. The difference between groups was analyzed using independent t-test. Results: We recruited 68 subjects, consisted of 34 elderly and 34 young adult subjects. After MenACWY-CRM197 vaccination, the total serum meningococcal-specific IgG levels increased significantly in both groups (p <0.001), but changes in total serum meningococcal-specific IgG levels in the elderly was significantly lower than in young adults (p=0.001). Conclusion: Compared to young adults, the increase in total serum meningococcal-specific IgG levels after meningococcal vaccination in the elderly group were significantly lower, confirming the effect of immunosenescence.