Table 2.
Protective effects of neutralizing antibodies in nonhuman primates challenge studies.
| Vaccines | Immunization procedure | Challenge dose | Neutralizing antibodies | Viral load (copies/ml) in BAL fluid | Ref | ||||
|---|---|---|---|---|---|---|---|---|---|
| Dosage | Doses | Interval (weeks) | Method | geometric mean titer(GMT) | Control | Vaccine | |||
| mRNA-1273 | 100 μg | 2 | 4 | 7.6 × 105 PFU | PV | 1862 | D4: ~7 × 105 | D4: < LLOD | (72) |
| BNT162b2 | 100 μg | 2 | 3 | 1.05 × 106 PFU | PV | 310 | D3: ~1 × 106 | D4: < LLOD | (73) |
| Ad26.COV2.S | 5 × 1010 vp | 2 | 8 | 1 × 105 TCID50 | PV | ~1000 | D4: ~1 × 105 | D4: < LLOD | (74) |
| ChAdOx1 nCoV19 | 2.5 × 1010 vp | 1 | _ | 2.6 × 106 TCID50 | Live-CPE | ~20 (5–40) | D3: ~1 × 105 | D3: < LLOD | (75) |
| 2.5 × 1010 vp | 2 | 4 | 2.6 × 106 TCID50 | Live-CPE | 10–160 | _ | _ | (76) | |
| BBIBP-CorV | 2/8 μg | 2 | 2 | 106 TCID50 | Live-CPE | 215/256 | ~1× 103-1 × 106 (lung) | < LLOD (lung) | (77) |
| PiCoVacc | 6 μg | 3 | 1 | 106 TCID50 | Live-CPE | ~50 | ~1× 103-1 × 106 (lung) | < LLOD (lung) | (78) |
| BBV152 | 3 μg | 2 | 2 | 1.25 × 106.5 TCID50 | Live-PRNT | ~3100 | D3: ~1 × 106 | < LLOD | (79) |
| INO-4800 | 1 mg | 1/2 | 4 | 5 × 106 PFU | Live-PRNT | 2199 | 1 × 106 | 1 × 104 | (80) |
| NVX-Cov2373 | 50 μg | 2 | 3 | 1.1 × 104 PFU | Live-CPE | 23040 | sgRNA ~ < 1E4 | < LLOD | (81) |
| SCB-2019 | 30 μg | 2 | 3 | 2.6 × 106 TCID50 | Live-CPE | 2700/35047 | D2: 1 × 104 | < LLOD | (82) |
vp, viral particles; PFU, plaque-forming units; TCID50, tissue culture infective dose 50; CPE, cytophatic effect detection assay; PRNT, plaque reduction neutralisation test; LLOD, lower limits of detection; BAL, Bronchoalveolar lavage.