Table III.
Ranking of COVID-19 vaccine candidates according to their efficacy in non-human primates
| Rank | Vaccine candidate | Number of doses needed (should not be >2, as per the WHO) | Viral clearance | Lung histopathology | T cell response | NAb response | |
|---|---|---|---|---|---|---|---|
| First detected at (should be detected within two weeks, as per the WHO) | Detected till | ||||||
| 1 | mRNA-1273 (100 μg) | 2 | Complete clearance from pulmonary and extra-pulmonary organs by 7 DPI | Mild inflammation compared to placebo group | Th1-biased response. Additional T-helper cell response | Week 2 | Week 8 |
| 2 | Ad26.COV2.S | 1 | Complete clearance from pulmonary organs, 2 DPI onwards | Not studied | Th1-biased response | Week 2 | Week 4 |
| 3 | NVX-CoV2373 (25 μg + 50 μg M-1) and (5 μg + 50 μg M-1) | 2 | Complete clearance from pulmonary organs, not detectable 2 DPI onwards | Nil-to-mild changes in vaccinated animals compared to placebo group | Th1-biased response | Week 3 | Week 5 |
| 4 | BNT162b2 | 2 | Complete viral clearance starting from 3 DPI and lasting upto 10 DPI in pulmonary organs, with 1 vaccinated animal showing presence of virus in throat swab on 10 DPI | Data not available | Th1-biased response | Week 3 | Week 8 |
| 5 | RBD | 2 | Undetectable sgRNA levels in pulmonary organs and GIT starting from 2 DPI and lasting up to 6 DPI, thus depicting viral clearance. gRNA was, however, detectable in vaccinated animals | Nil-to-mild changes in vaccinated animals compared to placebo group | Data not available | Week 1 | Peak at week 5 |
| 6 | BBV152 (3μg + adjuvant B and 6 μg+adjuvant B) | 2 | Complete viral clearance from pulmonary and extra-pulmonary organs by 7 DPI | Nil-to-mild histopathological changes in vaccinated group compared to placebo group | T-helper cell response | Week 3 | 7 DPI (week 5) |
| 7 | BBIBP-CorV (8 μg) | 2 or 4 | Complete clearance from throat and lungs and incomplete clearance from GIT in R. macaques by 7 DPI | Nil-to-mild histopathological changes in vaccinated group compared to placebo group | Not significant in C. macaques | Week 1 | Week 5 |
| 8 | ChAdOx-1nCoV-19 | 1 or 2 | Incomplete clearance from pulmonary and extra-pulmonary organs by 7 DPI | No pneumonia in vaccinated animals. Evidence of viral interstitial pneumonia in placebo group | Low Th1/Th2 response | Week 2 | Week 8 |
| 9 | PiCoVacc (6 μg) | 3 | Complete viral clearance from pulmonary and extra-pulmonary organs by 7 DPI | Nil-to-mild histopathological changes in vaccinated group compared to placebo group | Not significant | Week 2 | 7 DPI (week 5) |
| 10 | MRT 5500 | 2 | Not done | Not done | Th1-biased response | Week 1 | Week 5 |
| 11 | Sad23L-nCoV-S/Ad49L-nCoV-S | 2 | Not done | Not done | Th1-biased response | Week 2 | Week 10 |
| 12 | ARCoV | 2 | Not done | Not done | Th1-biased response | Week 2 | Peak at Week 4 |
| 13 | S-Trimer | 2 | Ineffective viral clearance, with 1 or more vaccinated animal showing presence of virus in pulmonary organs by 7 DPI in both vaccinated groups. However, no vaccinated animal had detectable virus in lung tissue on 7 DPI | Nil-to-mild changes in vaccinated animals compared to placebo group | Better lymphocyte response in CpG-1018 + alum-vaccinated group | Week 2 | Week 6 |
| 14 | INO-4800 | 2 | Ineffective viral clearance from pulmonary organs by 7 DPI | Not done | IFN-γ raised in vaccinated animals | Week 4 | Week 12 |
| 15 | GX-19 | 3 | Ineffective viral clearance from pulmonary organs by 4 DPI (necropsy) | Mild changes as compared to placebo group | Th1-biased response | 5.5 wk | Rising at week 8 |
| 16 | LION/repRNA-CoV2S | 1 or 2 | Not done | Not done | Not significant | Week 2 | Week 10 |
| 17 | S1-Fc | 3 | Not done | Not done | Data not available | 2-3 wk | Peak at week 5 |
| 18 | Inactivated vaccine | 2 | Not possible to comment | Nil-to-mild histopathological changes in vaccinated group compared to placebo group | Not significant | Not possible to comment | Not possible to comment |