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Table 4 Vaccine effectiveness against Delta variant and vaccine efficacy (clinical trials carried out prior to Delta strain being detected)

From: Effectiveness of the BNT162b2 (Pfizer-BioNTech) and the ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccines for reducing susceptibility to infection with the Delta variant (B.1.617.2) of SARS-CoV-2

References Infection Delay Dose 1 Effectiveness Dose 2 Effectiveness
Dose 1 Dose 2 Oxford-AstraZeneca Pfizer-BioNTech Oxford-AstraZeneca Pfizer-BioNTech
\(\begin{array}{c}\displaystyle \text {Core Model}\\ \displaystyle (\gamma =1/7)\end{array}\) Sym. & Asym. 21 14 \(\begin{array}{c}\displaystyle 38.5\%\\ \displaystyle [34.3,42.6]\end{array}\) \(\begin{array}{c}\displaystyle 19.5\%\\ \displaystyle [10.4,28.1]\end{array}\) \(\begin{array}{c}\displaystyle 64.0\%\\ \displaystyle [61.4,66.5]\end{array}\) \(\begin{array}{c}\displaystyle 83.9\%\\ \displaystyle [82.1,85.6]\end{array}\)
Bernal et al. [5] Sym. 21 14 \(\begin{array}{c}\displaystyle 30.0\%\\ \displaystyle (24.3,35.3)\end{array}\) \(\begin{array}{c}\displaystyle 35.6\%\\ \displaystyle (22.7,46.4)\end{array}\) \(\begin{array}{c}\displaystyle 67.0\%\\ \displaystyle (61.3,71.8)\end{array}\) \(\begin{array}{c}\displaystyle 88.0\%\\ \displaystyle (85.3,90.1)\end{array}\)
Pouwels et al. [6] Sym. & Asym. 21 14 \(\begin{array}{c}\displaystyle 46\%\\ \displaystyle (35,55)\end{array}\) \(\begin{array}{c}\displaystyle 57\%\\ \displaystyle (50,63)\end{array}\) \(\begin{array}{c}\displaystyle 67\%\\ \displaystyle (62,71)\end{array}\) \(\begin{array}{c}\displaystyle 80\%\\ \displaystyle (77,83)\end{array}\)
Sheikh et al. [7] Sym. & Asym. 28 14 \(\begin{array}{c}\displaystyle 33\%\\ \displaystyle (23,41)\end{array}\) \(\begin{array}{c}\displaystyle 33\%\\ \displaystyle (15,47)\end{array}\) \(\begin{array}{c}\displaystyle 61\%\\ \displaystyle (51,70)\end{array}\) \(\begin{array}{c}\displaystyle 83\%\\ \displaystyle (78,87)\end{array}\)
\(\begin{array}{c}\displaystyle \text {Sensitivity to } \gamma \\ \displaystyle (\gamma =1/11)\end{array}\) Sym. & Asym. 21 14 \(\begin{array}{c}\displaystyle 40.8\%\\ \displaystyle [36.2,45.1]\end{array}\) \(\begin{array}{c}\displaystyle 14.4\%\\ \displaystyle [4.52,23.5]\end{array}\) \(\begin{array}{c}\displaystyle 62.5\%\\ \displaystyle [59.6,65.1]\end{array}\) \(\begin{array}{c}\displaystyle 83.7\%\\ \displaystyle [81.8,85.5]\end{array}\)
\(\begin{array}{c}\displaystyle \text {Sensitivity to } \gamma \\ \displaystyle (\gamma =1/3)\end{array}\) Sym. & Asym. 21 14 \(\begin{array}{c}\displaystyle 35.3\%\\ \displaystyle [31.2,39.2]\end{array}\) \(\begin{array}{c}\displaystyle 26.3\%\\ \displaystyle [18.1,34]\end{array}\) \(\begin{array}{c}\displaystyle 66.2\%\\ \displaystyle [63.8,68.4]\end{array}\) \(\begin{array}{c}\displaystyle 84.2\%\\ \displaystyle [82.5,85.8]\end{array}\)
\(\begin{array}{c}\displaystyle \text {Double Removed}\\ \displaystyle (\gamma =1/7)\end{array}\) Sym. & Asym. 21 14 \(\begin{array}{c}\displaystyle 36.4\%\\ \displaystyle [31.9,40.6]\end{array}\) \(\begin{array}{c}\displaystyle 18.3\%\\ \displaystyle [9.14,26.9]\end{array}\) \(\begin{array}{c}\displaystyle 63.3\%\\ \displaystyle [60.7,65.8]\end{array}\) \(\begin{array}{c}\displaystyle 83.7\%\\ \displaystyle [81.8,85.3]\end{array}\)
     Dose 1 Efficacy Dose 2 Efficacy
Polack et al. [30] Sym. 12 7 \(\begin{array}{c}\displaystyle 52\%\\ \displaystyle [29.5,68.4]\end{array}\) \(\begin{array}{c}\displaystyle 95\%\\ \displaystyle [90.3,97.6]\end{array}\)
Voysey et al. [31] Sym. 21 14 \(\begin{array}{c}\displaystyle 64.1\%\\ \displaystyle [50.5,73.9]\end{array}\) \(\begin{array}{c}\displaystyle 70.4\%\\ \displaystyle [54.8,80.6] \\ \text {95.8\% credible interval}\end{array}\)
  1. Delay is the number of days after which the effectiveness or efficacy is measured, and \(\gamma\) is the recovery rate. 95% credible interval shown in square brackets \([\ ]\) and 95% confidence interval shown in parentheses \((\ )\), unless stated otherwise. The infection column specifies whether infection is symptomatic and asymptomatic ( Sym. & Asym.) or symptomatic (Sym.)