evidence: The COVID-19 vaccine lessens the severity of COVID-19 by teaching the immune system to recognize and fight the virus that causes the disease. [...] What should parents know about the COVID-19 vaccine and children? [...] Natural immunity is the antibody protection your body creates against a germ once you’ve been infected with it. Natural immunity to the virus that causes COVID-19 is no better than vaccine-acquired immunity, and it comes with greater risks. Studies show that natural immunity to the virus weakens over time and does so faster than immunity provided by COVID-19 vaccination.