Table 1 Effectiveness in individuals older than 18 years of age in B.1.1.7- and B.1.617.2-dominant periods

From: Effect of Delta variant on viral burden and vaccine effectiveness against new SARS-CoV-2 infections in the UK

 

BNT162b2: one dose ≥21 d

ChAdOx1: one dose ≥21 d

BNT162b2: second dose 0–13 d ago

ChAdOx1: second dose 0–13 d ago

BNT162b2: second dose ≥14 d

ChAdOx1: second dose ≥14 d

Not vaccinated, previously positivea

VE: all infections

1 December 2020–16 May 2021 (B.1.1.7)

59% (52–65%)

63% (55–69%)

77% (66–84%)

72% (50–84%)

78% (68–84%)

79% (56–90%)

60% (50–68%)

17 May 2021 (B.1.617.2)

57% (50–63%)

46% (35–55%)

82% (75–87%)

71% (64–77%)

80% (77–83%)

67% (62–71%)

72% (58–82%)

Heterogeneity P

0.60

0.004

0.29

0.99

0.50

0.23

0.12

VE: Ct <30

1 December 2020–16 May 2021 (B.1.1.7)

70% (65–74%)

74% (69–79%)

83% (75–89%)

79% (62–88%)

94% (91–96%)

86% (71–93%)

87% (84–90%)

17 May 2021 (B.1.617.2)

62% (56–68%)

50% (41–59%)

81% (73–86%)

69% (61–76%)

84% (82–86%)

70% (65–73%)

77% (66–85%)

Heterogeneity P

0.04

<0.0001

0.57

0.25

<0.0001

0.04

0.02

VE: self-reported symptoms

1 December 2020–16 May 2021 (B.1.1.7)

73% (68–76%)

73% (67–77%)

92% (88–95%)

84% (72–91%)

97% (96–98%)

97% (93–98%)

80% (75–84%)

17 May 2021 (B.1.617.2)

58% (51–64%)

40% (28–50%)

93% (90–95%)

73% (66–79%)

84% (82–86%)

71% (66–74%)

82% (73–88%)

Heterogeneity P

<0.0001

<0.0001

0.71

0.08

<0.0001

<0.0001

0.59

  1. aRe-infection will be a variable amount of time previously, but it was not possible to split this owing to low numbers.
  2. Note: All estimates (VE = 100% × (1 odds ratio)) were obtained from a generalized linear model with a logit link comparing to the reference category of ‘Not vaccinated, not previously positive and ≥21 d before vaccination’ and using clustered robust standard errors. Heterogeneity P values were obtained using the two-sided Wald test without adjustment for multiple comparisons. Calendar time was split into two epochs when most cases detected in the survey were ORF1ab + N positive (B.1.1.7 compatible) and then when triple positives became dominant (B.1.617.2 compatible) (Extended Data Fig. 1). Estimates from the former are similar to those from individuals aged ≥16 years previously published on data to 8 May 2021 but with slightly wider 95% CIs due to splitting time after the second dose at 14 d in this analysis. See Supplementary Table 4 for unadjusted heterogeneity P values. VE post-second doses changes over time from vaccination (see Fig. 2 and Extended Data Figs. 4 and 5 for changes in individuals aged 18–64 years), so estimates in this table are an average over follow-up included in this analysis.
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