The effect of selenium on immunogenicity of influenza vaccine in the elderly: A case-control double-blinded clinical trial

Introduction: Influenza can cause more severe diseases and higher rate of morbidity and mortality in the elderly population. Therefore, they should receive influenza vaccine annually. However, the host response to vaccine is less in older individuals. On the other hand, selenium can act as a stimulator of the immune system and cause increased immunity and response to vaccine. This study was carried out to determine the effect of selenium on antibody production against influenza vaccine. By verifying this effect, selenium can be recommended as an adjuvant therapy in the elderly. Methods: A total of 110 subjects were selected at Infectious Diseases Research Center of Imam Reza Hospital in Kermanshah. They were divided into two groups of adjuvant (N=56) and placebo (N=54). The adjuvant group received influenza vaccine and selenium tablet. The placebo group received influenza vaccine and placebo tablet. Venous blood samples were taken before and four weeks after vaccination and the results were compared between the two groups. Results: Seroconversion, seroprotection, and geometric mean titer (GMT) for three strains (H1N1, H3N2, and B) were assessed. The seroconversion and GMT rates against influenza B vaccine component were significantly higher in adjuvant group than placebo group. Conclusion: Considering the ability of selenium in induction of a better response to influenza vaccine in older people as well as its low cost and accessibility, selenium can be used to increase antibody level in such cases.