Summary of findings:

NVX-CoV2373 compared to Placebo for vaccination against COVID-19

Patient or population:
Setting:
Intervention:
Comparison:

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

№ of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with Placebo

Risk with NVX-CoV2373

Incidence of participants with positive test for SARS-CoV-2 infection - not reported
-
-
-
-
-
Outcome not yet measured or reported
Incidence of symptomatic COVID-19 confirmed with positive test for SARS-CoV-2 d
1,498 per 100,000
344 per 100,000
(75 to 1,633)
Rate ratio 0.23
(0.05 to 1.09)
16723
(2 RCTs)
e

VERY LOW
b,f,g,h
Vaccine efficacy 89.70% (95%CI 80.20% to 94.60%) and 49.40% (95% CI 6.1% to 72.8%)
Severe or critical disease due to COVID-19 d
72 per 100,000
12 per 100,000
(1 to 99)
RR 0.16
(0.02 to 1.38)
16723
(2 RCTs)
e

VERY LOW
b,g,i
Vaccine efficacy: not reported
All-cause mortality j
0 per 100,000
0 per 100,000
(0 to 0)
not estimable
14039
(1 RCT)
k

VERY LOW
b,c,l
Zero events in both groups
Any adverse events m
203 per 1,000
240 per 1,000
(209 to 274)
RR 1.18
(1.03 to 1.35)
16667
(4 RCTs)
n

MODERATE
g
Serious adverse events m
5 per 1,000
5 per 1,000
(3 to 8)
RR 1.02
(0.67 to 1.56)
16107
(2 RCTs)
e

VERY LOW
g,i
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: Confidence interval; RR: Risk ratio
GRADE Working Group grades of evidence
High certainty: We are very confident that the true effect lies close to that of the estimate of the effect
Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different
Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect
Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect

Explanations

a. Last updated: 01 July, 2021
b. Despite some concerns with deviations from intervention, not downgraded for risk of bias.
c. Indirectness downgraded by one level: data are from an interim analysis of the trial, with a short duration of follow-up. Estimates may change over a longer duration of follow-up.
d. Median follow-up: 3 months (Measured from 7 days after the 2nd dose)
e. Heath P, 2021; Shinde V, 2021
f. Inconsistency downgraded by 1 level: I²=91.7%
g. Indirectness downgraded by one level: data are from an interim analyses of the trials, with a short duration of follow-up. Estimates may change over a longer duration of follow-up.
h. Imprecision downgraded by 1 level: due to wide confidence interval consistent with the possibility for no effect and the possibility for benefit.
i. Imprecision downgraded by 2 levels: due to wide confidence interval consistent with the possibility for benefit and the possibility for harm and few events.
j. Median follow-up: 3 months
k. Heath P, 2021
l. Imprecision downgraded by 2 levels: no events in either group
m. Unsolicited adverse events, median follow up time 3 months
n. Heath P, 2021; Shinde V, 2021; Formica N, 2021; Keech C, 2020