Summary of findings 1. Effectiveness against measles.
| Effectiveness against measles | |||||
| Patient or population: children 9 months to 15 years old Setting: general population or school or day‐care centre or general practitioner or households Intervention: MMR vaccine Comparison: unvaccinated | |||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | |
| Risk of measles amongst unvaccinated | Risk of measles amongst vaccinated | ||||
| Cohort studies ‐ 1 dose | Study population | RR 0.05 (0.02 to 0.13) | 12,039 (7 observational studies) | ⊕⊕⊕⊝ MODERATE1 | |
| 66 per 1000 | 3 per 1000 (1 to 9) | ||||
| Cohort studies ‐ 2 doses | Study population | RR 0.04 (0.01 to 0.28) | 21,604 (5 observational studies) | ⊕⊕⊕⊝ MODERATE1 | |
| 19 per 1000 | 1 per 1000 (0 to 5) | ||||
| Cohort studies household contacts ‐ 1 dose | Study population | RR 0.19 (0.04 to 0.89) | 151 (3 observational studies) | ⊕⊕⊝⊝ LOW | |
| 508 per 1000 | 97 per 1000 (20 to 452) | ||||
| Cohort studies household contacts ‐ 2 doses | Study population | RR 0.15 (0.03 to 0.75) | 378 (3 observational studies) | ⊕⊕⊝⊝ LOW | |
| 508 per 1000 | 76 per 1000 (15 to 381) | ||||
| Cohort studies household contacts ‐ 3 doses | Study population | RR 0.04 (0.01 to 0.23) | 151 (2 observational studies) | ⊕⊕⊝⊝ LOW | |
| 351 per 1000 | 14 per 1000 (4 to 81) | ||||
| Cohort studies postexposure prophylaxis | Study population | RR 0.26 (0.14 to 0.50) | 283 (2 observational studies) | ⊕⊕⊝⊝ LOW | |
| 314 per 1000 | 82 per 1000 (44 to 157) | ||||
| *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; MMR: measles, mumps, rubella vaccine; 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. | |||||
1Upgraded one level for large effect size (non‐critical risk of bias in studies).