Table 1.
Characteristics of included studies
| Author/year | Type of study/NOS score | Country/n° pts received three doses | Setting/median follow‐up | Immunosoppressive therapies | Previous vaccine type/n° doses (%) | Third dose timing from second dose | Third dose type |
|---|---|---|---|---|---|---|---|
| Barda/2021 | Observational (vs. matched‐control with two doses) Ministry of Health criteria/9 | Israel/728 321 | General population/13 days | 3.6% | ‐/2 (100) | ≥5 months | BNT162b2 |
| Bar‐on/2021 | Retrospective/9 | Israel (Ministry of Health)/1 137 804 | ≥60 years/7 days | 0% | ‐/2 (100) | ≥5 months | BNT162b2 |
| Benotmane/2021 | Retrospectkive/7 | France/159 | Kidney transplant | 100% | mRNA‐1273 (Moderna)/2 (100) | ≥1 month and <50 AU/ml | mRNA‐1273 |
| Bensouna/2021 | Prospective case series/7 | French/69 | Hemodialysis or peritoneal dialysis/30 days | 13% | BNT162b2/2 (100) | ≥1 month | BNT162b2 |
| Bertrand/2021 | Retrospective/7 | France/80 | Kidney transplant/‐ | 100% (various) | BNT162b2/2 (100) | ≥1 month | BNT162b2 |
| Chavarot/2021 | Retrospective/7 | France/62 | Kidney transplant/44 days | 100% (betalacept + steroids) | BNT162b2/2 (100) | 69.5 days (median) | BNT162b2 |
| Dekervel/2021 | Two prospective cohorts/6 | France/66 + 34 | Hemodialysis/NR | 11% | BNT162b2/2 (100) | ≥1 month | BNT162b2 |
| Del Bello/2021 | Retrospective/8 | France/396 | Solid organ transplant | 100% | BNT162b2/2 (100) | ‐ | BNT162b2 |
| Eliakim‐Raz/2021 | Retrospective (Israel, Rabin Medical Center)/7 | Israel/97 | ≥60 years/NR | 0% | ‐/2 (100) | ‐ | BNT162b2 |
| Falsey/2021 | Retrospective analysis of a Phase 1‐2‐3 trial/7 | US/11 + 12 (two cohorts) | ≥18 years/30 days | 0% | BNT162b2/2 (100) | 7.9–8.8 months | BNT162b2 |
| Flaxman/2021 | Retrospective analysis of UK COV001 and COV002/7 | UK/75 | ≥18 years/‐ | 0% | ChAdOx1 nCoV‐19/2 (100) | 20–38 weeks | AZD1222 |
| Gounant/2021 | Retrospective/7 | France/30 | Cancer patients/‐ | 100% | BNT162b2/2 (100) | 4 weeks | BNT162b2 |
| Hall/2021 | Randomized study (vaccine vs. placebo)/‐ | Canada/60 | Transplant patients/‐ | 100% | mRNA‐1273/2 (100) | 2 months | mRNA‐1273 |
| Karaba/2021 | Retrospective/6 | US/47 | Transplant recipients/‐ | 77% | 64% BNT162b2 or mRNA‐1273/2 (100) | ≥2 months | 70% mRNA, 30% Ad26. COV2.S |
| Keskin/2021 | Retrospective/6 | Turkey/45 | Healthcare workers/‐ | 0% | CoronaVac/2 (100) | ≥1 month | CoronaVac or BNT162b2 |
| Le Bourgeois/2021 | Retrospective/7 | France/80 | Allogeneic hematopoietic stem cell transplant/119 days | 23.7% | BNT162b2/2 (100) | ≥1 month | BNT162b2 |
| Marlet/2021 | Retrospective/8 | France/180 | Kidney transplant (160) and CLL (20)/NR | 100% | BNT162b2 and mRNA‐1273/2 (100) | ≥1 month | BNT162b2 or mRNA‐1273 |
| Massa/2021 | Prospective longitudinal study/6 | France/61 | Kidney transplant/‐ | 100% (various) | BNT162b2/2 (100) | 1 month | BNT162b2 |
| Masset/2021 | Retrospective/6 | France/71 | Kidney transplant/‐ | 100% | BNT162b2/2 (100) | ‐ | BNT162b2 |
| Westhoff/2021 | Retrospective/5 | Germany/10 | Kidney transplant/‐ | 100% | BNT162b2/2 (100) | 4–12 weeks | mRNA‐1273 |
| Peled/2021 | Retrospective/7 | Israel/96 | Heart transplant/18 days b | 79% | BNT162b2/2 (100) | 168 days | BNT162b2 |
| Redjoul/2021 | Retrospective/7 | France/42 | Allogenic HSCT/53 days | NR | BNT162b2/2 (100) | 2 months | BNT162b2 |
| Robert/2021 | Retrospective/6 | France/18 | Hemodialysis/28 days | NR | BNT162b2/2 (100) | ‐ | BNT162b2 |
| Saciuk/2021 | Retrospective cohort study/8 | Israel/865 887 | General population/70 days | 0% | BNT162b2/2 (100) | 6 months | BNT162b2 |
| Schmiedeberg/2021 | Retrospective/7 | Switzerland/17 | Rheumatoid arthritis/2 weeks | Temporarily discontinued | mRNA‐1273 and BNT162b2/2 (100) | ≥4 months | mRNA‐based from the same manufacturer |
| Shroff/2021 | Retrospective/6 | US/20 (Third dose) | Cancer patients/5–11 days | 100% | BNT162b2/2 (100) | ‐ | BNT162b2 |
| Tillmann/2021 | Prospective cohort/5 | Germany/10 | Hemodialysis/‐ | 29.4% | mRNA (94%)/2 (100) | ‐ | mRNA |
| Werbel/2021 | Retrospective series/5 | US/30 | Organ transplant/‐ | 100% | mRNA(100%)/2 (100) | 67 days (median) | mRNA (50%) and Ad26. COV2.S (50%) |
| Yang/2021 | Phase 1 and randomized Phase 2 studies/‐ | China/40 + 450a | 18–59 years/‐ | 0% | ‐/2 (100) | 1 month | ZF2001 Ab targeting receptor binding domain (RBD) of the SARS‐CoV‐2 S protein |
| Yuer/2021 | Retrospective/7 | China/67 | Cohort voluntarily/1 month b | NA | Inactivated vaccine/2 (100) | 8 months | Inactivated vaccine |
Abbreviations: NA, not applicable; NOS, Nottingham–Ottawa Scale; ‐, not reported.
a
Patients that received three doses in Phase 1 + Phase 2 studies.
b
Time to serum collection.