Summary of findings 2. Casirivimab/imdevimab compared to placebo for pre‐exposure prophylaxis of COVID‐19.
| Casirivimab/imdevimab compared to placebo in previously uninfected and unvaccinated people | ||||||
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Patient or population: SARS‐CoV‐2 uninfected people without defined exposure, or with potential exposure to SARS‐CoV‐2 Setting: preventive measures Intervention: casirivimab/imdevimab Comparison: placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | N° of participants (studies) | Certainty in the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with casirivimab/imdevimab | |||||
| Infection with SARS‐CoV‐2 within 6 monthsa | 96 per 1000 |
1 per 1000 (0 to 13) |
RR 0.01 (0.00 to 0.14) |
825 (1 RCT) |
⊕⊕⊝⊝ Lowb,c |
Casirivimab/imdevimab may decrease infection with SARS‐CoV‐2 within 6 months in participants SARS‐CoV‐2 antibody seronegative at baseline. Participants may have been exposed to SARS‐CoV‐2 wild‐type and variants such as Alpha and Delta. |
| Development of clinical COVID‐19 symptoms within 6 months | 42 per 1000 |
1 per 1000 (0 to 11) |
RR 0.02 (0.00 to 0.27) |
969 (1 RCT) |
⊕⊕⊝⊝ Lowb,c |
Casirivimab/imdevimab may decrease development of clinical COVID‐19 symptoms within 6 months. Participants may have been exposed to SARS‐CoV‐2 wild‐type and variants such as Alpha and Delta. |
| All‐cause mortality within 6 months | 1 study reported mortality by week 24. There were no deaths. | Not estimable | 969 (1 RCT) |
⊕⊝⊝⊝ Very lowb,d |
The evidence is very uncertain about the effect of casirivimab/imdevimab on mortality. Participants may have been exposed to SARS‐CoV‐2 wild‐type and variants such as Alpha and Delta. |
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| Admission to hospital within 6 months | — | — | — | — | We identified no studies reporting admission to hospital. | |
| Quality of life at longest follow‐up | — | — | — | — | We identified no studies reporting quality of life. | |
| Adverse events: grade 1 to 2 | — | — | — | — | We identified no studies reporting grade 1 to 2 adverse events. | |
| Adverse events: grade 3 to 4 within 6 months | 13 per 1000 |
6 per 1000 (1 to 24) |
RR 0.44 (0.10 to 1.95) |
969 (1 RCT) |
⊕⊝⊝⊝ Very lowb,e |
The evidence is very uncertain about the effect of casirivimab/imdevimab on the occurrence of grade 3 to 4 adverse events within 6 months. Participants may have been exposed to SARS‐CoV‐2 wild‐type and variants such as Alpha and Delta. |
| Adverse events: all grades within 6 months | 483 per 1000 |
551 per 1000 (474 to 633) |
RR 1.14 (0.98 to 1.31) |
969 (1 RCT) |
⊕⊕⊝⊝ Lowb,f |
Casirivimab/imdevimab may increase the occurrence of all‐grade adverse events within 6 months slightly. Participants may have been exposed to SARS‐CoV‐2 wild‐type and variants such as Alpha and Delta. |
| Serious adverse events within 6 months | 8 per 1000 |
7 per 1000 (1 to 35) |
RR 0.82 (0.16 to 4.21) |
969 (1 RCT) |
⊕⊝⊝⊝ Very lowb,e |
The evidence is very uncertain about the effect of casirivimab/imdevimab on the occurrence of serious adverse events within 6 months. Participants may have been exposed to SARS‐CoV‐2 wild‐type and variants such as Alpha and Delta. |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk on the comparison group and the relative effect of the intervention (and its 95% confidence interval). CI: confidence interval; mAb: monoclonal antibody; RCT: randomised controlled trial; RR: risk ratio; SARS‐CoV‐2: severe acute respiratory syndrome coronavirus 2. | ||||||
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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 the 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. | ||||||
aThe outcome was assessed in participants SARS‐CoV‐2 antibody seronegative at baseline. bDowngraded one level for serious risk of bias (missing information regarding randomisation process and allocation concealment). cDowngraded one level for serious imprecision, because of low number of events. dDowngraded two levels for very serious imprecision, because there were no events, effect not estimable. eDowngraded two levels for very serious imprecision, because of very low number of events and very wide confidence intervals. fDowngraded one level for very serious imprecision, because of wide confidence intervals.