What type of vaccine should be avoided for patients with a history of severe allergic reactions?

Live-attenuated vaccines are derived from weakened forms of the virus or bacteria they protect against. In patients with a history of severe allergic reactions, particularly those associated with anaphylaxis, live-attenuated vaccines may pose a higher risk. This is because the process used to produce these vaccines can introduce residues from the vaccine's culture medium or stabilizers that might trigger an allergic response in susceptible individuals.

Alternatives such as inactivated vaccines, subunit vaccines, and toxoid vaccines are typically considered safer for individuals with a history of severe allergic reactions. These types of vaccines do not contain live pathogens, which significantly reduces the risk of eliciting an allergic response. Inactivated vaccines are made from viruses or bacteria that have been killed, subunit vaccines consist of only specific pieces of the virus or bacteria, and toxoid vaccines contain inactivated toxins. Therefore, for patients with severe allergies, live-attenuated vaccines are generally avoided to ensure their safety.