Introduction
Methods
Information sources and search strategy
Eligibility criteria
Study selection and data collection
Data items
Risk of bias and quality assessment
Results
Study characteristics and demographic data
Effectiveness of previous infection in protecting against reinfection with Omicron compared to pre-Omicron variants such as Delta
Study | Country/Study type | Description | Delta (or other) infected cohorts | Omicron infected cohorts |
---|---|---|---|---|
Altarawaneh et al. [56] | Case control study Qatar | aPIE overall | Alpha: 90.2% (60.2–97.6) Beta: 85.7% (75.8–91.7) Delta: 92.0% (87.9–94.7) | 56.0% (50.6–60.9) |
aPIE adjusted for vaccine status | Alpha: 90.3% (60.4–97.6) Beta: 85.1% (74.5–91.3) Delta: 91.9% (87.8–94.7) | 55.9% (50.5–60.8) | ||
aPIE vaccinated excluded | Alpha: 95.3% (66.0–99.3) Beta: 85.4% (72.4–92.2) Delta: 90.2% (81.9–94.6) | 61.9% (48.2–72.0) | ||
aPIE against severe, critical, or fatal COVID-19 | Alpha: 69.4% (− 143.6–96.2) Beta: 88.0% (50.7–97.1) Delta: 100% (43.3–100) | 87.8% (47.5–97.1) | ||
Šmíd et al. [57] | Czech Republic Database based study | b,cPIE against infection (overall) | Shortly after infection 95% (94–96) After 6 months 83% (82–84) | Shortly after infection 68% (68–69) After 6 months 13% (11–14) |
b,cPIE against infection (not vaccinated) | 2–6 months after previous infection 93% (91–94) 7–10 months 91% (90%–92%) 11–14 months 86% (85–86) ≥ 14 months 79% (77–81) | 2–6 months after previous infection 69% (68–69) 7–10 months 48% (46–50) 11–14 months 34% (33–35) ≥ 14 months 17% (15–18) | ||
b,cPIE against hospitalization overall | < 6 months 100% (no case) > 6 months 94% (91–96) | < 6 months 73% (55–84) > 6 months 66% (54–75) | ||
b,cPIE against hospitalization Full vaccination < 2 month ago | < 6 months 100% (no case) > 6 months 97% (91–99) | < 6 months 100% (no case) > 6 months 94% (77–95) | ||
b,cPIE against hospitalization Full vaccination > 2 month ago | < 6 months 100% (no case) > 6 months 98% (98–100) | < 6 months 93% (49–99) > 6 months 73% (78–99) | ||
b,cPIE against hospitalization Booster < 2 month ago | < 6 months 100% (no case) > 6 months 99% (99–100) | < 6 months 100% (no case) > 6 months 95% (78–99) | ||
b,cPIE against hospitalization Booster > 2 month ago | < 6 months 100% (no case) > 6 months 98% (85%–100%) | < 6 months 71% (0–96) > 6 months 90% (64%–98%) | ||
b,cPIE against oxygen therapy overall | < 6 months 100% (no case) > 6 months 98% (95%–99%) | < 6 months 81% (40%–94%) > 6 months 88% (72%–94%) | ||
b,cPIE against ICU overall | < 6 months 100% (no case) > 6 months 97% (90%–99%) | < 6 months 83% (0–98%) > 6 months 66% (15%–86%) |
Rates of previously infected individuals in omicron infected cohorts compared with cohorts infected with other variants
Study | Country/Study type | Description | Negative cohorts % (n/N) | Delta (or other) infected cohorts % (n/N) | Omicron infected cohorts % (n/N) or % (n) | P value |
---|---|---|---|---|---|---|
Eggink et al. [35] | Netherlands Case only approach cohort study | Naïve (no PI no vaccine) | - | 37.1% (34,765/93734) | 27.4% (22,071/80615) | NR |
PI unvaccinated | - | 1.4% (1295/93734) | 6.5% (5253/80615) | NR | ||
Andeweg et al. [61] | Netherlands Cohort study Of the infected people the presented % were: | Naïve (no PI no vaccine) | 30.2% (90,945/300849) | 52.8% (21,042/39889) | 24.7% (3440/13915) BA.1 | NR |
PI unvaccinated | 4.2% (12,691/300849) | 1.6% (638/39889) | 5.3% (739/13915) BA.1 | NR | ||
First start primary vaccination, then infection | 1.1% (3406/300849) | 0.2% (76/39889) | 1.7% (240/13915) BA.1 | NR | ||
First infection, then primary vaccination | 2.3% (7002/300849) | 0.3% (139/39889) | 2.1% (293/13915) BA.1 | NR | ||
PI, booster | 0.3% (918/300849) | 0% (2/39889) | 0.5% (65/13915) BA.1 | NR | ||
Kahn et al. [45] | Sweden Cohort study | PI unvaccinated (0–1 dose) | - | 2.7% (265/9680) | 7.1% (562/7861) PI | NR |
Vaccinated (2–3 dose) | - | 2.3% (94/4031) | 6.3% (1376/21678) PI | NR | ||
Kislaya et al. [46] | Portugal Data linkage Case-case study | Naïve (no PI no vaccine) | - | 10.6% (888) | 6% (315) | NR |
PI unvaccinated | - | 1.3% (108) | 6.2% (327) | NR | ||
No PI partial vaccination | - | 1.3% (112) | 1.3% (68) | NR | ||
PI partial/complete vaccination | - | 0.3% (25) | 0.84% (44) | NR | ||
No PI complete vaccination | - | 88.6% (7245) | 85.7% (4515) | NR | ||
Nunes et al. [39] | South Africa Cohort study | PI | 41.6% (101) | - | 27.9% (53) | 0.003 |
Naïve (no PI no vaccine) | 10.8% (23) | - | 13.2% (23) | NR | ||
PI, no vaccines | 6.5% (14) | - | 5.2% (9) | NR | ||
No PI, J&J | 48.6% (104) | - | 56.9% (99) | NR | ||
PI + J&J | 34.1% (73) | - | 24.7% (43) | NR | ||
Spensley et al. [41] | UK Cohort study | PI overall | 53.5% (516/965) | - | 43.4% (63/145) | 0.024 |
PI + ChAdOx1 | - | - | 46.2% (226/489) | 0.75 | ||
PI + BNT1262b2 | - | - | 47.2% (260/551) | 0.75 |
Study | Country/Study type | Description | Negative cohorts % (n/N) | Delta (or other) infected cohorts % (n/N) | Omicron infected cohorts % (n/N) or % (n) | P value |
---|---|---|---|---|---|---|
Lewnard et al. [58] | USA Cohort study | 15 December 2021 to 17 January 2022 (Documented PI) | - | 0.4% (84/23305) | 0.5% (1,163/222688) | NR |
3 February to 17 March 2022 (Documented PI) | - | - | 0.6% (75/12756) BA.1 0.4% (7/1905) BA.2 | NR | ||
Stegger et al. [59] | Denmark Danish COVID-19 surveillance | Rate of second infection when PI with BA.1 | - | 0% (0/263) | 6.46% (17/263) BA.1 17.87% (47/263) BA.2 | NR |
Rate of second infection when PI with BA.2 | - | 0% (0/263) | 0% (0/263) BA.1 1.14% (3/263) BA.2 | NR | ||
Rate of second infection when PI with Delta | - | 11.4% (30/263) | 9.88% (26/263) BA.1 53.23% (140/263) BA.2 | NR | ||
Rate of second infection when PI (overall) | - | 11.4% (30/263) | 12.54% (33/263) BA.1 72.24% (190/263) BA.2 | NR | ||
Andrews et al. [60] | UK Test-negative case–control | Rate of PI out of the Delta and Omicron | 16.5% (260,073/1572621) | 1.8% (3,754/204154) | 11.1% (98,150/886774) | NR |
Espenhain et al. [38] | Denmark Data from the routine Danish surveillance of COVID-19 | PI | - | 0.9% (160/19137) | 4.3% (34/785) | NR |
Davies et al. [42] | South Africa Cohort study | HR for PI (vs. None) | - | - | Death 1.10 (0.63—1.92) Severe hospitalization or death 0.60 (0.37—0.98) Hospitalization or death 0.28 (0.19—0.40) | - |
PI | - | Wave 3 (Delta, 20/5/2021 to 23/6/2021) 3.2% (140/4403) | Wave 4 (Omicron, 14/11/2021 to 11/12/2021) 11.3% (580/5144) | - | ||
Peralta-Santos et al. [49] | Portugal Cohort Study National network group of laboratories | PI | - | 1.6% (146/9397) | 6.8% (449/6581) | < 0.001 |
Wolter et al. [51] | South Africa Data linkage study | aPI | - | 4.5% (43/948) (non SGTF) | 10.4% (1100/10 547) (SGTF) | 0.18 |
Ward et al. [52] | UK Data linkage aPI | PI | - | 1% (2211/221146) | 6.6% (53,724/814003) | NR |
Garg et al. [53] | India Cohort study | PI | - | 8.2% (6/182) | 17.1% (14/82) | NR |
Krutikov et al. [54] | UK Prospective cohort study | PI | - | Pre-Omicron 4.3% (17/400) | 12.7% (236/1864) | < 0.0001 |
Shrestha et al. [36] | USA Retrospective cohort study | PI | - | - | 2.9% (88/4585) symptomatic 1.5% (2/133) hospitalized | - |
Hajjo et al. [47] | Jordan Questionnaire based study | Reinfected within 90 days | - | - | 8.6% (43/500) of which: 41.9% (18/43) asymptomatic 44.2% (19/43) mild 2.3% (1/43) moderate 2.3% (1/43) severe 9.3% (4/43) unspecified | - |
Smith-Jeffcoat et al. [37] | USA Cohort (convention attendees) | PI | 0% (0/7) | - | 6.25% (1/16) | NR |
Sharma et al. [40] | Rajasthan, India Cohort study | PI | - | - | 43.2% (126) | - |
MMWR [43] | USA Cohort study | PI | - | - | 14% (6/43) | - |
Madhi et al. [44] | South Africa seroepidemiologic survey | PI | - | - | 2.8% (195) | - |
Maisa et al. [48] | France Questionnaire based | PI | - | - | 14% (39/278) 2% hospitalized (7/294) – of these 7, 2 PI | - |
Qassim et al. [50] | Qatar Cross sectional study | No PI | - | - | 90.8% (141,839) | - |
PI < 90 days before the study | - | - | 0.4% (560) | - | ||
PI overall | - | - | 8.8% (13,803) | - |