Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 16 3 2024 06 19 401 410 Hassan Yarmohammadi Department of Microbiology, North Tehran Branch, Islamic Azad University, Tehran, Iran; Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran Mohammadreza Aghasadeghi Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran Abbas Akhavan Sepahi Department of Microbiology, North Tehran Branch, Islamic Azad University, Tehran, Iran Mojtaba Hamidi-fard Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran Golnaz Bahramali Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran 2024 02 06 2024 05 27 Background and Objectives: Rotavirus and Hepatitis A virus are responsible for causing gastroenteritis and jaundice. The current vaccination approaches have proven insufficient, especially in low-income countries. In this study, we presented a novel dual-vaccine candidate that combines the rotavirus VP8 protein and the hepatitis A virus VP1. Materials and Methods: The VP8*-rotavirus+AAY+HAV-VP1 fusion protein was produced using an Escherichia coli expression system. The recombinant protein had a molecular weight of approximately 45.5 kDa and was purified through affinity chromatography. BALB/c mice were injected subcutaneously with the recombinant protein, VP1, VP8 and vaccines for rotavirus and hepatitis A virus, both with and without ALUM and M720 adjuvants. ELISA assays were used to measure total IgG, IgG1, IgG2, and short-term and long-term IL-5 and IFN-γ responses. Results: The fusion protein, when combined with adjuvants, elicited significantly higher total IgG, IgG1, and IgG2 responses compared to VP1 and VP8 alone, as well as the rotavirus and hepatitis A vaccines. Furthermore, it induced a higher short-term IL-5 and IFN-γ response while demonstrating a higher long-term IL-5 response compared to the rotavirus and hepatitis A vaccines. Conclusion: This study demonstrates that the VP8*-rotavirus+AAY+HAV-VP1 fusion protein is a promising dual vaccine candidate for immunization against hepatitis A and rotaviruses. https://ijm.tums.ac.ir/index.php/ijm/article/view/4600 https://ijm.tums.ac.ir/index.php/ijm/article/download/4600/1682