Available vaccine platforms
| Pros | Cons | Approved vaccines in use | |
|---|---|---|---|
| Whole inactivated (killed) virus | Easily manufactured Strong immune response Mature technique | Possible Th2 bias Requires large quantities of virus Risk of vaccine-enhanced disease Requires booster shots | Influenza, rabies, hepatitis A, injectable polio |
| Live attenuated virus | Entire viral repertoire Very strong cytotoxic response Mature technique | Risk of reversion/recombination Risk of infection in immunocompromised patients Requires cold chain distribution | Measles, rubella, mumps, yellow fever |
| Protein subunits | Simple to produce Safe, few side effects | Less immunogenic Requires adjuvants Slower manufacture | Influenza A strains, hepatitis B, acellular pertussis |
| Viral-like protein | Safe and stable Immunogenicity | Enveloped VLP more challenging to produce | HPV, preclinical SARS-CoV-1 |
| DNA | Rapid development Noninfectious Thermostable | Potential integration to host genome Less Immunogenicity Delivery challenging; requires cold chain distribution | Not currently licensed |
| mRNA | Rapid development Noninfectious, non-integrating | Instability Low immunogenicity Delivery challenging; requires cold chain distribution | SARS-CoV-2: EUA from FDA (Pfizer, Moderna) |
| Viral vectors | Safe Durable response | Pre-existing immunity against vector | Ebola. SARS-CoV-2: EUA from FDA (Johnson & Johnson) |
EUA = emergency use authorization; FDA = Food and Drug Administration; HPV = human papilloma virus; mRNA = messenger ribonucleic acid; SARS-CoV = severe acute respiratory syndrome; Th2 = T helper type-2 cells; VLP = viral-like protein