Table 2.
Cross-neutralization of SARS-CoV-2 WT and Delta variant.
| Serum ID | Infection/Vaccination status | Sample History | Vaccine type | Ab titer (WT) | Ab titer (Delta) | Significance (T test) | |
|---|---|---|---|---|---|---|---|
| History of exposure to WT SARS-CoV-2 | SR-6 | W1 | Day 15 | NA | 16 | 8 | p < 0.041 |
| SR-8 | W1 | Day 18 | NA | 32 | <8 | ||
| SR-9 | W1 | Day 10 | NA | 16 | 8 | ||
| SR-13 | W1 | Day 14 | NA | 32 | 0 | ||
| SR-14 | W1 | Day11 | NA | 32 | 8 | ||
| SR-17 | W1 | Day 12 | NA | 16 | 8 | ||
| SR-18 | W1 | Day 14 | NA | 32 | 0 | ||
| SR-19 | W1 | Day 15 | NA | 32 | 16 | ||
| SR-21 | W1 | Day 10 | NA | <8 | <8 | ||
| SR-116A* | W1 | Day 29 | NA | 32 | <8 | ||
| SR-119 | W1V | Day 98 (2nd dose) | Covishield | 256 | 16 | ||
| SR-125 | V | Day 40 (2nd dose) | Covishield | 32 | 16 | ||
| SR-127 | W1 | Day 105 | NA | 128 | 32 | ||
| SR-132 | V | Day 42 (2nd dose) | Covishield | 16 | 16 | ||
| SR-133 | V | Day 22 (1st dose) | Covishield | 16 | 8 | ||
| SR-134 | V | Day 48 (2nd dose) | Covishield | 128 | 128 | ||
| SR-135 | V | day 19 (1st dose) | Covishield | 16 | 0 | ||
| SR-136 | V | Day 30 (2nd dose) | Covaxin | 16 | <8 | ||
| SR-137 | V | Day 109 (2nd dose) | Covishield | 32 | 8 | ||
| SR-138 | V | Day 28 (2nd dose) | Covishield | 32 | 16 | ||
| SR-139 | V | Day 10 (2nd dose) | Covaxin | 128 | 128 | ||
| SR-140 | V | Day 57 (2nd dose) | Covishield | 16 | 8 | ||
| SR-141 | V | Day 62 (2nd dose) | Covishield | 128 | 64 | ||
| SR-142 | V | Day 58 (2nd dose) | Covishield | 16 | <8 | ||
| SR-143 | V | Day 58 (2nd dose) | Covishield | 32 | 16 | ||
| SR-144 | V | Day 84 (2nd dose) | Covishield | 32 | 16 | ||
| History of exposure to Delta SARS-CoV-2 | SR-126 | W2 | Day 45 | NA | 32 | 128 | p < 0.035 |
| SR-128 | W2 | Day 51 | NA | 32 | 128 | ||
| SR-129 | W2 | Day 22 | NA | 16 | 32 | ||
| SR-130 | W2 | Day 56 | NA | 16 | 64 | ||
| SR-131 | W2 | Day 37 | NA | <8 | 32 | ||
| Exposure to both WT and Delta variant | SR-116B* | W1W2 | Day 18 (2nd infection) | NA | 64 | 128 | NA |
| SR-124 | W2V | Day 34 (1st dose) | Covishield | 64 | 64 |
Pairwise statistical comparison of antibody titers in serum samples (WT versus Delta variant) was performed by two-tailed Student’s t-test. For statistical analysis, antibody titer <8 was considered as 8.
W1, infection during the first wave; W2, infection during the second wave; V, uninfected but vaccinated; W1V, infected during the first wave and then vaccinated; W2V, infection during the second wave and later vaccinated; Ab, antibody; NA, not applicable.
*The individual infected during both the first and second waves (SR116A, sample collected at 29 days post-first wave infection; SR116B, sample collected at 18 days post-second wave infection).