ORCID Profile
0000-0002-6135-0018
Current Organisation
World Health Organization
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Publisher: Wiley
Date: 21-01-2013
DOI: 10.1111/IRV.12074
Publisher: Springer Science and Business Media LLC
Date: 30-05-2022
Publisher: Cold Spring Harbor Laboratory
Date: 04-10-2022
DOI: 10.1101/2022.10.02.22280610
Abstract: We aimed to systematically review the magnitude and duration of the protective effectiveness of prior infection (PE) and hybrid immunity (HE) against Omicron infection and severe disease. We searched pre-print and peer-reviewed electronic databases for controlled studies from January 1, 2020, to June 1, 2022. Risk of bias (RoB) was assessed using the Risk of Bias In Non-Randomized Studies of Interventions (ROBINS-I)-Tool. We used random-effects meta-regression to estimate the magnitude of protection at 1-month intervals and the average change in protection since the last vaccine dose or infection from 3 months to 6 or 12 months. We compared our estimates of PE and HE to previously published estimates of the magnitude and durability of vaccine effectiveness (VE) against Omicron. Eleven studies of prior infection and 15 studies of hybrid immunity were included. For prior infection, there were 97 estimates (27 at moderate RoB and 70 at serious RoB), with the longest follow up at 15 months. PE against hospitalization or severe disease was 82·5% [71·8-89·7%] at 3 months, and 74·6% [63·1-83·5%] at 12 months. PE against reinfection was 65·2% [52·9-75·9%] at 3 months, and 24·7% [16·4-35·5%] at 12 months. For HE, there were 153 estimates (78 at moderate RoB and 75 at serious RoB), with the longest follow up at 11 months for primary series vaccination and 4 months for first booster vaccination. Against hospitalization or severe disease, HE involving either primary series vaccination or first booster vaccination was consistently % for the available follow up. Against reinfection, HE involving primary series vaccination was 69·0% [58·9-77·5%] at 3 months after the most recent infection or vaccination, and 41·8% [31·5-52·8%] at 12 months, while HE involving first booster vaccination was 68·6% [58·8-76·9%] at 3 months, and 46·5% [36·0-57·3%] at 6 months. Against hospitalization or severe disease at 6 months, hybrid immunity with first booster vaccination (effectiveness 95·3% [81·9-98·9%]) or with primary series alone (96·5% [90·2-98·8%]) provided significantly greater protection than prior infection alone (80·1% [70·3-87·2%]), first booster vaccination alone (76·7% [72·5-80·4%]), or primary series alone (64·6% [54·5-73·6%]). Results for protection against reinfection were similar. Prior infection and hybrid immunity both provided greater and more sustained protection against Omicron than vaccination alone. All protection estimates waned quickly against infection but remained high for hospitalisation or severe disease. In iduals with hybrid immunity had the highest magnitude and durability of protection against all outcomes, reinforcing the global imperative for vaccination. WHO COVID-19 Solidarity Response Fund and the Coalition for Epidemic Preparedness Innovations. The global emergence and rapid spread of Omicron (B.1.1.529) variant of concern, characterized by their ability to escape immunity, has required scientists and policymakers to reassess the population protection against Omicron infection and severe disease. So far, few systematic reviews have incorporated data on Omicron, and none have examined the protection against Omicron conferred by hybrid immunity (i.e. the immunity gained from the combination of vaccination and prior infection) which is now widespread globally. While one preprint has recently reported protection from prior infection over time, no systematic review has systematically compared the magnitude and duration of vaccination, prior infection, and hybrid immunity. A large single-country study has reported that protection from either infection or hybrid immunity against Omicron infection wanes to low levels at 15 months, but is relatively stable against severe disease. Prior infection and hybrid immunity both provided greater and more sustained protection against Omicron than vaccination alone. In iduals with hybrid immunity had the highest magnitude and durability of protection against all outcomes protection against severe disease remained above 95% until the end of available follow-up at 11 months after hybrid immunity with primary series and 4 months after hybrid immunity with booster vaccination, and was sustained at these high levels of protection in projections to 12 months and 6 months, respectively. These results may serve to tailor guidance on the optimal number and timing of vaccinations. At the public health level, these findings can be combined with data on local infection prevalence, vaccination rates, and their timing. In settings with high seroprevalence, limited resources, and competing health priorities, it may be reasonable to focus on achieving high coverage rates with primary series among in iduals who are at higher risk of poor outcome, as this will provide a high level of protection against severe disease for at least one year among those with prior infection. Furthermore, given the waning protection for both infection-and vaccine induced immunity against infection or reinfection, mass vaccination could be timed for roll-out prior to periods of expected increased incidence, such as the winter season. At the in idual level, these results can be combined with knowledge of a person’s infection and vaccination history. A six-month delay in booster may be justified after the last infection or vaccination for in iduals with a known prior infection and full primary series vaccination. Further follow-up of the protective effectiveness of hybrid immunity against hospitalization or severe disease for all vaccines is needed to clarify how much waning of protection might occur with longer duration since the last infection or vaccination. Producing estimates of protection for new variant-containing vaccines will be crucial for COVID-19 vaccine policy and decision-making bodies. Policy makers considering the use and timing of vaccinations should include the local extent of past infection, the protection conferred by prior infection or hybrid immunity, and the duration of this protection as key considerations to inform their decision-making.
Publisher: Elsevier BV
Date: 05-2016
Publisher: Wiley
Date: 16-06-2022
DOI: 10.1111/IRV.13002
Abstract: We aimed to estimate the household secondary infection attack rate (hSAR) of SARS‐CoV‐2 in investigations aligned with the WHO Unity Studies Household Transmission Investigations (HHTI) protocol. We conducted a systematic review and meta‐analysis according to PRISMA 2020 guidelines. We searched Medline, Embase, Web of Science, Scopus and medRxiv/bioRxiv for “Unity‐aligned” First Few X cases (FFX) and HHTIs published 1 December 2019 to 26 July 2021. Standardised early results were shared by WHO Unity Studies collaborators (to 1 October 2021). We used a bespoke tool to assess investigation methodological quality. Values for hSAR and 95% confidence intervals (CIs) were extracted or calculated from crude data. Heterogeneity was assessed by visually inspecting overlap of CIs on forest plots and quantified in meta‐analyses. Of 9988 records retrieved, 80 articles (64 from databases 16 provided by Unity Studies collaborators) were retained in the systematic review 62 were included in the primary meta‐analysis. hSAR point estimates ranged from 2% to 90% (95% prediction interval: 3%–71% I 2 = 99.7%) I 2 values remained % in subgroup analyses, indicating high, unexplained heterogeneity and leading to a decision not to report pooled hSAR estimates. FFX and HHTI remain critical epidemiological tools for early and ongoing characterisation of novel infectious pathogens. The large, unexplained variance in hSAR estimates emphasises the need to further support standardisation in planning, conduct and analysis, and for clear and comprehensive reporting of FFX and HHTIs in time and place, to guide evidence‐based pandemic preparedness and response efforts for SARS‐CoV‐2, influenza and future novel respiratory viruses.
Publisher: Public Library of Science (PLoS)
Date: 26-11-2013
Publisher: Wiley
Date: 20-04-2011
Publisher: Cold Spring Harbor Laboratory
Date: 03-04-2022
DOI: 10.1101/2022.04.01.22273107
Abstract: We aimed to estimate the household secondary infection attack rate (hSAR) of SARS-CoV-2 in investigations aligned with the WHO Unity Studies Household Transmission Investigations (HHTI) protocol. We conducted a systematic review and meta-analysis according to PRISMA 2020 guidelines. We searched Medline, Embase, Web of Science, Scopus and medRxiv/bioRxiv for ‘Unity-aligned’ First Few X cases (FFX) and HHTIs published between 1 December 2019 and 26 July 2021. Standardised early results were shared by WHO Unity Studies collaborators (to 1 October 2021). We used a bespoke tool to assess investigation methodological quality. Values for hSAR and 95% confidence intervals (CIs) were extracted or calculated from crude data. Heterogeneity was assessed by visually inspecting overlap of CIs on forest plots and quantified in meta-analyses. Of 9988 records retrieved, 80 articles (64 from databases 16 provided by Unity Studies collaborators) were retained in the systematic review and 62 were included in the primary meta-analysis. hSAR point estimates ranged from 2%–90% (95% prediction interval: 3%–71% I 2 =99.7%) I 2 values remained % in subgroup analyses, indicating high, unexplained heterogeneity and leading to a decision not to report pooled hSAR estimates. FFX and HHTI remain critical epidemiological tools for early and ongoing characterisation of novel infectious pathogens. The large, unexplained variance in hSAR estimates emphasises the need to further support standardisation in planning, conduct and analysis, and for clear and comprehensive reporting of FFX and HHTIs in time and place, to guide evidence-based pandemic preparedness and response efforts for SARS-CoV-2, influenza and future novel respiratory viruses.
Publisher: Public Library of Science (PLoS)
Date: 06-2010
Publisher: Springer Science and Business Media LLC
Date: 16-04-2014
Publisher: Springer Science and Business Media LLC
Date: 20-02-2023
Publisher: Public Library of Science (PLoS)
Date: 05-07-2011
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Maria Van Kerkhove.