Table 2.
The effects of Delta variant on neutralizing antibody
| Vaccine | Serological assay | Samples | Reference objects | Serum specimen | Median age | Country | Result | Reference |
|---|---|---|---|---|---|---|---|---|
| BNT162B2 | Pseudovirus | 20 | Wild type | Two doses | NA | USA | GMT: wild type was 502 B.1.617.2-spike was 355 B.1.617.2-v2-spike was 343 | [22] |
| Live virus | 250 | Wild type | Two doses One dose | 42 | UK | Two doses: NAbTs: 5.8-fold reduced (95% CI 5.0–6.9) One dose: 68% had low NAbTs (IC50* < 40) | [63] | |
| Pseudovirus | 36 | Wild type | Two doses | 48 | Israel | Delta-S1#: NAbTs: 2.6-fold reduced (95% CI, 1.8–3.5) Delta-S2: NAbTs: 2.1-fold reduced (95% CI, 1.7–2.5) | [82] | |
| Pseudovirus | 9 | D614G | Two doses | 31 | USA | NAbTs: 3.6-fold reduced | [83] | |
| ChAdOx1 | Live virus | 106 | BNT162B2 Wild type | Two doses One dose | 34 | UK | Two doses: NAbTs: 2.5-fold reduced (95% CI, 1.4–2.7) relative to BNT162B2 One dose: 85% (95% CI, 68%– 94%) had quantifiable NAbTs; 91% (95% CI, 75%–98%) wild type had quantifiable NAbTs | [63][64] |
| mRNA- 1273 | Pseudovirus | 8 | D614G | Two doses | 41 | USA | NAbTs: fourfold reduced | [83] |
NA: not available; GMT: geometric mean neutralizing titers; NAbT: neutralizing antibody titers. IC50*: 50% inhibitory concentration; #delta sample 1 (S1, hCoV-19/Israel/CVL-12804/2021) and sample 2 (S2, hCoV-19/Israel/CVL-12806/2021).