Subunit Vaccine

A subunit vaccine is a vaccine that contains purified parts of a pathogen that are antigenic, or necessary to elicit a protective immune response, rather than the whole pathogen itself, so it carries no risk of introducing the disease and tends to be safer and more stable than vaccines containing whole pathogens. It can be made from disassembled viral particles grown in cell culture or through recombinant DNA expression, in which case it is described as a recombinant subunit vaccine. The first recombinant subunit vaccine was produced in the mid-1980s to protect against hepatitis B, and other licensed recombinant subunit vaccines include Engerix-B for hepatitis B, Gardasil 9 for human papillomavirus, Flublok for influenza, Shingrix for herpes zoster and Nuvaxovid for COVID-19. Advantages of subunit vaccines include being a well-established technology and being suitable for immunocompromised individuals, while disadvantages include being relatively complex to manufacture and often requiring adjuvants and booster doses.