Table 1.
Mixed-model analysis of variables associated with anti-spike antibody titers after following two doses of vaccine in SARS-CoV-2 naïve cohorts.
| Variables (ratio of mean titer [95% CI]) | Peak titer (21-days after second dose) | End of study titer (6-months after second dose) |
|---|---|---|
| Age group | ||
| ≤60 years | Reference | Reference |
| >60 years | 0.78 [0.66–0.98] ∗∗ | 0.87 [0.67–1.98] |
| Gender | ||
| Female | Reference | Reference |
| Male | 1.13 [0.94–1.35] | 0.91 [0.68–1.16] |
| Body-mass index (BMI) | ||
| BMI <25 kg/m2 | Reference | Reference |
| BMI 25–29.9 kg/m2 | 0.95 [0.72–1.33] | 0.78 [0.33–14.82] |
| BMI ≥30 kg/m2 | 0.92 [0.71–1.42] | 0.83 [0.471–11.83] |
| Blood Group | ||
| AB+ | Reference | Reference |
| A+ | 1.13 [0.70–1.79] | 1.11 [0.64–2.49] |
| B+ | 1.39 [0.91–2.10] | 1.07 [0.69–2.98] |
| O+ | 1.52 [0.91–1.94] | 1.19 [0.64–2.01] |
| A- | 1.83 [0.62–3.28] | 0.69 [0.20–2.30] |
| B- | 1.23 [0.58–2.82] | 1.09 [0.46–3.08] |
| AB- | 0.81 [0.44–1.87] | 1.31 [0.48–5.94] |
| O- | 1.14 [0.57–2.31] | 1.16 [0.42–3.23] |
| Co-morbidities | ||
| Any co-morbidities | 0.88 [0.71–0.96] ∗∗ | 0.77 [0.62–1.07] |
| No co-morbidities | Reference | Reference |
| Type 2 Diabetes Mellitus (T2DM) | ||
| Yes, T2DM | 0.88 [0.76–1.35] | 0.77 [0.63–1.39] |
| No, T2DM | Reference | Reference |
| Duration of T2DM | ||
| Duration <5 years | Reference | Reference |
| Duration 5–10 years | 1.26 [0.37–4.24] | 1.87 [0.02–18.67] |
| Duration >10 years | 0.56 [0.23–1.36] | 0.84 [0.03–19.86] |
| Hypertension (HTN) | ||
| Yes, HTN | 0.95 [0.83–1.31] | 0.46 [0.15–0.77] ∗∗ |
| No, HTN | Reference | Reference |
| Duration of HTN | ||
| Duration <5 years | Reference | Reference |
| Duration 5–10 years | 0.82 [0.15–11.42] | 1.44 [0.65–3.17] |
| Duration >10 years | 0.76 [0.26–5.64] | 1.01 [0.49–1.86] |
| Dyslipidaemia | ||
| Yes, Dyslipidaemia | 0.72 [0.40–6.13] | 0.82 [0.45–6.61] |
| No, Dyslipidaemia | Reference | Reference |
| Ischemic Heart Disease (IHD) | ||
| Yes, IHD | 0.82 [0.46–1.43] | 2.93 [0.53–4.60] |
| No, IHD | Reference | Reference |
| Vaccine type (SARS-CoV-2 naive, N = 360) | ||
| Covishield | 1.62 [1.15–2.26] ∗∗ | 1.37 [0.77–1.59] |
| Covaxin | Reference | Reference |
| Vaccine type (SARS-CoV-2 naive, propensity-matched, n = 41) | ||
| Covishield | 1.72 [1.18–2.63] ∗∗ | 1.46 [0.83–1.67] |
| Covaxin | Reference | Reference |
aThe peak period was defined as days 21 through day 28 after the receipt of second dose of vaccine, whereas end of study was defined as day 180 through days 187 after the receipt of second dose; ∗∗P < 0.05; SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2.