Table 2.
Benefits and Drawbacks of Immunogens Used in Vaccines (WHO, 2021).
Immunogen | Description | Benefits | Drawbacks | Examples |
---|---|---|---|---|
Inactivated virus | Inactivated dead virus | Triggers powerful antibody response | Needs significant amount of virus and shows low or no cellular response | Influenza, hepatitis A, and rabies |
Viral subunit | A pathogen-derived protein | Fewer side effects compared to the whole virus (swelling or redness at the injection site) | Complex process and may be poorly immunogenic | Influenza |
Viral vector | Viral pathogen expressed on a safe virus, does not result in disease | Fast development, powerful cellular response, and easier to produce | Prior exposure to vector virus (eg. adenovirus) is likely to lower immunogenicity, certain vectors need boosting with another vector | Ebola |
Nucleic acid | mRNA coding for a viral protein | Fast development and powerful cellular immunity | Reduced antibody response | COVID-19 |