No; it is not necessary to get an antibody test after you are fully vaccinated (two doses of the Moderna or Pfizer vaccine or one dose of the Johnson & Johnson (Janssen) vaccine). The vaccine stimulates the immune system in many ways, only one of which is to produce the IgG antibodies we test for when looking for evidence of protection. Also, the COVID-19 antibody tests currently available under the FDA’s Emergency Use Authorization have variable sensitivity and specificity and are not authorized for the assessment of immune response in vaccinated people. In fact, it is possible to be effectively immunized despite a negative post-vaccination antibody test; it is also unknown what level of antibodies might ensure protection. For these reasons, and in accordance with CDC guidelines, we do not recommend routine antibody testing after receiving the vaccine. In certain high-risk immunosuppressed populations, physicians may recommend such testing.