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Bergeri, I.; Whelan, M.; Ware, H.; Subissi, L.; Nardone, A.; Lewis, H. C.; Li, Z.; Ma, X.; Valenciano, M.; Cheng, B.; Ariqi, L. A.; Rashidian, A.; Okeibunor, J.; Azim, T.; Wijesinghe, P.; Le, L. V.; Vaughan, A.; Pebody, R.; Vicari, A.; Yan, T.; Yanes-Lane, M.; Cao, C.; Cheng, M. P.; Papenburg, J.; Buckeridge, D.; Bobrovitz, N.; Arora, R. K.; van Kerkhove, M. D.; Al-Shoteri, S.; Aly, E. A.; Audu, R. A.; Barakat, A.; Bin-Ghouth, A. S.; Birru, E.; Bokonjic, D.; Bolotin, S.; Boucher, E. L.; Catovic-Baralija, E.; Ceban, A.; Chauma-Mwale, A.; Chimeddorj, B.; Chung, P. S.; Clifton, D.; Dabakuyo-Yonli, T. S.; Deveaux, G. R.; Diop, B.; Dokubo, E. K.; Donnici, C.; Duarte, N.; Duarte, N. A.; Evans, T. G.; Fairlie, L.; Freidl, G. S.; Harris, T. G.; Herring, B. L.; Iamsirithaworn, S.; Ila, R.; Ilincic, N.; Ilori, E. A.; Inbanathan, F. Y.; Indenbaum, V.; Kaldor, J.; Kim, D.; Kolawole, O. M.; Kondwani, J. C.; Kuchuk, T.; Lalwani, P. J.; Laman, M.; Lavu, E.; Leite, J.; Liu, M.; Loeschnik, E.; Macartney, K.; Machalek, D. A.; Makiala-Mandanda, S.; Mallet, H. P.; Mapira, P.; Mawien, P. N.; Misra, P.; Musa, S.; Mutevedzi, P. C.; Najjar, O. A.; Nakphook, S.; Noel, K. C.; Nurmatov, Z.; Ome-Kaius, M.; Paudel, K. P.; Perlman-Arrow, S.; Qaddomi, S. E.; Quan, H.; Rady, A.; Rahim, H. P.; Rayyan, I. Y.; Rodriguez, A.; Sachathep, K.; Segal, M.; Selemon, A.; Shirin, T.; Stafford, K. A.; Steinhardt, L.; Tran, V.; Traore, I. T.; Wahyono, T. Y. M.; Williamson, T.; Wood, N.; Yansouni, C. P.; Zhang, C.; Lin, C. Z..
Preprint in English | EMBASE | ID: ppcovidwho-326828


Background COVID-19 case data underestimates infection and immunity, especially in low- and middle-income countries (LMICs). We meta-analyzed standardized SARS-CoV-2 seroprevalence studies to estimate global seroprevalence. Objectives/Methods We conducted a systematic review and meta-analysis, searching MEDLINE, Embase, Web of Science, preprints, and grey literature for SARS-CoV-2 seroprevalence studies aligned with the WHO UNITY protocol published between 2020-01-01 and 2021-10-29. Eligible studies were extracted and critically appraised in duplicate. We meta-analyzed seroprevalence by country and month, pooling to estimate regional and global seroprevalence over time;compared seroprevalence from infection to confirmed cases to estimate under-ascertainment;meta-analyzed differences in seroprevalence between demographic subgroups;and identified national factors associated with seroprevalence using meta-regression. PROSPERO: CRD42020183634. Results We identified 396 full texts reporting 736 distinct seroprevalence studies (41% LMIC), including 355 low/moderate risk of bias studies with national/sub-national scope in further analysis. By April 2021, global SARS-CoV-2 seroprevalence was 26.1%, 95% CI [24.6-27.6%]. Seroprevalence rose steeply in the first half of 2021 due to infection in some regions (e.g., 18.2% to 45.9% in Africa) and vaccination and infection in others (e.g., 11.3% to 57.4% in the Americas high-income countries), but remained low in others (e.g., 0.3% to 1.6% in the Western Pacific). In 2021 Q1, median seroprevalence to case ratios were 1.9:1 in HICs and 61.9:1 in LMICs. Children 0-9 years and adults 60+ were at lower risk of seropositivity than adults 20-29. In a multivariate model using data pre-vaccination, more stringent public health and social measures were associated with lower seroprevalence. Conclusions Global seroprevalence has risen considerably over time and with regional variation, however much of the global population remains susceptible to SARS-CoV-2 infection. True infections far exceed reported COVID-19 cases. Standardized seroprevalence studies are essential to inform COVID-19 control measures, particularly in resource-limited regions.

PubMed; 2021.
Preprint in English | PubMed | ID: ppcovidwho-296807


Background: Countries in the World Health Organization (WHO) European Region differ in terms of the COVID-19 vaccine roll-out speed. We evaluated the health and economic impact of different age-based vaccine prioritisation strategies across this demographically and socio-economically diverse region. Methods: We fitted country-specific age-stratified compartmental transmission models to reported COVID-19 mortality in the WHO European Region to inform the immunity level before vaccine roll-out. Building upon broad recommendations from the WHO Strategic Advisory Group of Experts on Immunisation (SAGE), we examined four strategies that prioritise: all adults (V+), younger (20-59 year-olds) followed by older adults (60+) (V20), older followed by younger adults (V60), and the oldest adults (75+) (V75) followed by incremental expansion to successively younger five-year age groups. We explored four roll-out scenarios based on projections or recent observations (R1-4) - the slowest scenario (R1) covers 30% of the total population by December 2022 and the fastest (R4) 80% by December 2021. Five decision-making metrics were summarised over 2021-22: mortality, morbidity, and losses in comorbidity-adjusted life expectancy (cLE), comorbidity- and quality-adjusted life years (cQALY), and the value of human capital (HC). Six sets of infection-blocking and disease-reducing vaccine efficacies were considered. Findings: The optimal age-based vaccine prioritisation strategies were sensitive to country characteristics, decision-making metrics and roll-out speeds. Overall, V60 consistently performed better than or comparably to V75. There were greater benefits in prioritising older adults when roll-out is slow and when VE is low. Under faster roll-out, V+ was the most desirable option. Interpretation: A prioritisation strategy involving more age-based stages (V75) does not necessarily lead to better health and economic outcomes than targeting broad age groups (V60). Countries expecting a slow vaccine roll-out may particularly benefit from prioritising older adults. Funding: World Health Organization, Bill and Melinda Gates Foundation, the Medical Research Council (United Kingdom), the National Institute of Health Research (United Kingdom), the European Commission, the Foreign, Commonwealth and Development Office (United Kingdom), Wellcome Trust. Research in Context: Evidence before this study: We searched PubMed and medRxiv for articles published in English from inception to 9 Jun 2021, with the search terms: ("COVID-19" OR "SARS-CoV-2") AND ("priorit*) AND ("model*") AND ("vaccin*") and identified 66 studies on vaccine prioritization strategies. Of the 25 studies that compared two or more age-based prioritisation strategies, 12 found that targeting younger adults minimised infections while targeting older adults minimised mortality;an additional handful of studies found similar outcomes between different age-based prioritisation strategies where large outbreaks had already occurred. However, only two studies have explored age-based vaccine prioritisation using models calibrated to observed outbreaks in more than one country, and no study has explored the effectiveness of vaccine prioritisation strategies across settings with different population structures, contact patterns, and outbreak history. Added-value of this study: We evaluated various age-based vaccine prioritisation strategies for 38 countries in the WHO European Region using various health and economic outcomes for decision-making, by parameterising models using observed outbreak history, known epidemiologic and vaccine characteristics, and a range of realistic vaccine roll-out scenarios. We showed that while targeting older adults was generally advantageous, broadly targeting everyone above 60 years might perform better than or comparably to a more detailed strategy that targeted the oldest age group above 75 years followed by those in the next younger five-year age band. Rapid vaccine roll-out has only been observed in a small number of countries. If vaccine coverage can reach 80% by the end of 2021, prioritising older adults may not be optimal in terms of health and economic impact. Lower vaccine efficacy was associated with greater relative benefits only under relatively slow roll-out scenarios considered. Implication of all the available evidence: COVID-19 vaccine prioritization strategies that require more precise targeting of individuals of a specific and narrow age range may not necessarily lead to better outcomes compared to strategies that prioritise populations across broader age ranges. In the WHO European Region, prioritising all adults equally or younger adults first will only optimise health and economic impact when roll-out is rapid, which may raise between-country equity issues given the global demand for COVID-19 vaccines.

J Hosp Infect ; 119: 170-174, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1574292


This article presents and compares coronavirus disease 2019 attack rates for infection, hospitalization, intensive care unit (ICU) admission and death in healthcare workers (HCWs) and non-HCWs in nine European countries from 31st January 2020 to 13th January 2021. Adjusted attack rate ratios in HCWs (compared with non-HCWs) were 3.0 [95% confidence interval (CI) 2.2-4.0] for infection, 1.8 (95% CI 1.2-2.7) for hospitalization, 1.9 (95% CI 1.1-3.2) for ICU admission and 0.9 (95% CI 0.4-2.0) for death. Among hospitalized cases, the case-fatality ratio was 1.8% in HCWs and 8.2% in non-HCWs. Differences may be due to better/earlier access to treatment, differential underascertainment and the healthy worker effect.

COVID-19 , Health Personnel , Hospitalization , Humans , Intensive Care Units , SARS-CoV-2