What are the contraindications for administering live vaccines?

Severe immunosuppression is a well-established contraindication for administering live vaccines due to the nature of these vaccinations. Live vaccines contain weakened forms of the viruses or bacteria they aim to protect against, which are still capable of inducing an immune response. In individuals with severely compromised immune systems—due to conditions such as congenital immunodeficiency, cancer treatments (like chemotherapy), or significant use of immunosuppressive medications—their bodies might not only fail to mount an adequate immune response but could also allow the attenuated virus or bacteria to reactivate and cause disease.

In contrast, conditions such as a common cold, allergies to eggs, and minor cuts or scrapes do not represent true contraindications for live vaccines. A mild respiratory infection should not interfere with vaccine efficacy or safety. Allergies to eggs are more relevant to certain vaccines (like the influenza vaccine) but do not necessarily contraindicate all live vaccines. Likewise, minor cuts or scrapes do not pose a risk that would inhibit the administration of live vaccines to an individual.