Exactly. Some vaccines like the polio vaccine are inactivated, or dead, virus injected into you that your body doesn't know is dead and creates antibodies to fight the apparent infection. Many of the influenza vaccines are irradiated or weakened viruses injected into you to cause the same response. Covid19 vaccine is basically a man-made chemical that makes the body think its been infected by covid19 and create antibodies. In all these cases the body thinks its under attack, goes into defense mode, creates antibodies, raises body temperature, etc.