Safety and effectiveness of single- versus double-dose of seasonal influenza vaccine in kidney transplant recipients: a randomized clinical trial

Abstract

Introduction. Influenza virus poses significant risks to immunocompromised individuals such as those who have received organ transplants and are undergoing immunosuppressive treatment to prevent transplant rejection. Therefore, annual influenza vaccination is recommended for these individuals. This study aimed to comparison of safety and effectiveness of single- versus double-dose of seasonal influenza vaccine in kidney transplant recipients. Materials and methods. This randomized clinical trial involved 50 kidney transplant recipients at Imam Khomeini Hospital. Participants were randomly assigned to two groups: those receiving a single dose (standard dose) and those receiving a double dose of the seasonal flu vaccine. Serum samples were collected before and 4 weeks after vaccination to measure influenza AB-related antibodies. Sixteen patients were excluded from the study. The trial focused on evaluating the vaccine safety and immunogenicity, as well as documenting any local and systemic side effects following vaccination. Results. The results indicated no significant difference in gender, age, and type of immunosuppressive drug used between the single- and double-dose groups (p 0.05). No significant difference in post-vaccination adverse effects, such as injection site pain (p = 0.21) between the two groups. The seroconversion rates (change from IgG 9 IU/µL to IgG 11 IU/µL) for IgG Influenza A were 12.5% (n = 2) in the single-dose group and 26.7% (n = 4) in the double-dose group, and for IgG Influenza B, they were 11.8% (n = 2) and 21.4% (n = 3), respectively. Conclusion. A double dose of the influenza vaccine slightly enhanced the immune response in kidney transplant patients without causing any adverse side effects.