Hello Thank you for posting at HCM ERIG is equine derived and hence carries more chances of side effects than HRIG, though both are safe when considered with the risk of not getting any of them after a bite. Usual side effects are mainly related to reactions and site infections leading to headaches, fever, chills, nausea, vomiting, itching, rash, allergic reaction, or injection site reactions (tenderness, pain, soreness, or stiffness of the muscles). You should get your shots as prescribed by your doc, there are multiple regimens available and doctors choose according to the site or extent of the injury Hope to have informed you sufficiently Feel free to ask a new question if you have any other query Thanks