Table 2.
Production and Clinical Development of Vaccines against Infectious Diseases.
| Vaccine Type | Ease of Production | Clinical Development * | Potential Issues |
|---|---|---|---|
| Attenuated | Variable | 140 Phase 1 71 Phase 2 43 Phase 3 |
Reversal of attenuation, storage, and distribution of a live vaccine |
| DNA | ++++ | 207 Phase 1 61 Phase 2 0 Phase 3 |
Limited immunogenicity in humans |
| Adenovirus | +++ | 69 Phase 1 21 Phase 2 1 Phase 3 |
Risk of adverse effects and immunity to vector |
| Recombinant proteins | ++++ or variable | 195 Phase 1 76 Phase 2 55 Phase 3 |
Most widely accepted, safe and immunogenic |
* Number of vaccine studies of the different phases registered in ClinicalTrials.gov, excluding COVID-19 vaccines (as of 30 October 2020).