Global SARS-CoV-2 seroprevalence from January 2020 to April 2022: A systematic review and meta-analysis of standardized population-based studies.

BACKGROUND: Our understanding of the global scale of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection remains incomplete: Routine surveillance data underestimate infection and cannot infer on population immunity; there is a predominance of asymptomatic infections, and uneven access to diagnostics. We meta-analyzed SARS-CoV-2 seroprevalence studies, standardized to those described in the World Health Organization's Unity protocol (WHO Unity) for general population seroepidemiological studies, to estimate the extent of population infection and seropositivity to the virus 2 years into the pandemic. METHODS AND FINDINGS: We conducted a systematic review and meta-analysis, searching MEDLINE, Embase, Web of Science, preprints, and grey literature for SARS-CoV-2 seroprevalence published between January 1, 2020 and May 20, 2022. The review protocol is registered with PROSPERO (CRD42020183634). We included general population cross-sectional and cohort studies meeting an assay quality threshold (90% sensitivity, 97% specificity; exceptions for humanitarian settings). We excluded studies with an unclear or closed population sample frame. Eligible studies-those aligned with the WHO Unity protocol-were extracted and critically appraised in duplicate, with risk of bias evaluated using a modified Joanna Briggs Institute checklist. 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 underascertainment; meta-analyzed differences in seroprevalence between demographic subgroups such as age and sex; and identified national factors associated with seroprevalence using meta-regression. We identified 513 full texts reporting 965 distinct seroprevalence studies (41% low- and middle-income countries [LMICs]) sampling 5,346,069 participants between January 2020 and April 2022, including 459 low/moderate risk of bias studies with national/subnational scope in further analysis. By September 2021, global SARS-CoV-2 seroprevalence from infection or vaccination was 59.2%, 95% CI [56.1% to 62.2%]. Overall seroprevalence rose steeply in 2021 due to infection in some regions (e.g., 26.6% [24.6 to 28.8] to 86.7% [84.6% to 88.5%] in Africa in December 2021) and vaccination and infection in others (e.g., 9.6% [8.3% to 11.0%] in June 2020 to 95.9% [92.6% to 97.8%] in December 2021, in European high-income countries [HICs]). After the emergence of Omicron in March 2022, infection-induced seroprevalence rose to 47.9% [41.0% to 54.9%] in Europe HIC and 33.7% [31.6% to 36.0%] in Americas HIC. In 2021 Quarter Three (July to September), median seroprevalence to cumulative incidence ratios ranged from around 2:1 in the Americas and Europe HICs to over 100:1 in Africa (LMICs). Children 0 to 9 years and adults 60+ were at lower risk of seropositivity than adults 20 to 29 (p < 0.001 and p = 0.005, respectively). In a multivariable model using prevaccination data, stringent public health and social measures were associated with lower seroprevalence (p = 0.02). The main limitations of our methodology include that some estimates were driven by certain countries or populations being overrepresented. CONCLUSIONS: In this study, we observed that global seroprevalence has risen considerably over time and with regional variation; however, over one-third of the global population are seronegative to the SARS-CoV-2 virus. Our estimates of infections based on seroprevalence far exceed reported Coronavirus Disease 2019 (COVID-19) cases. Quality and standardized seroprevalence studies are essential to inform COVID-19 response, particularly in resource-limited regions.

Development of a road map to scale up the uptake and utilization of influenza vaccine in 22 countries of Eastern Mediterranean Region.

BACKGROUND: The aim of this project was to develop a road map to support countries in Eastern Mediterranean Region in developing and implementing evidence-based seasonal influenza vaccination policy, strengthen influenza vaccination delivery program and address vaccine misperceptions and hesitancy. METHODS: The road map was developed through consultative meetings with countries' focal points, review of relevant literature and policy documents and analysis of WHO/UNICEF Joint Reporting Form on immunization ((JRF 2015-2020) data. Countries were categorised into three groups, based on the existence of influenza vaccination policy and national regulatory authority, availability of influenza vaccine in the country and number of influenza vaccine doses distributed/ 1000 population. The final road map was shared with representatives of all countries in Eastern Mediterranean Region and other stakeholders during a meeting in September 2021. RESULT: The goal for next 5 years is to increase access to and use of utilization of seasonal influenza vaccine in Eastern Mediterranean Region to reduce influenza-associated morbidity and mortality among priority groups for vaccination. Countries in the Eastern Mediterranean Region are at different stages of implementation of the influenza vaccination program, so activities are planned under four strategic priority areas based on current situations in countries. The consultative body recommended that some countries should establish a new seasonal influenza vaccination programme and ensure the availability of vaccines, while other countries need to reduce vaccine hesitancy and enhance current seasonal influenza vaccination coverage, particularly in all high-risk groups. Countries are also encouraged to leverage COVID-19 adult vaccination programs to improve seasonal influenza vaccine uptake. CONCLUSION: This road map was developed through a consultative process to scale up the uptake and utilization of influenza vaccine in all countries of Eastern Mediterranean Region. The road map proposes activities that should be adopted in the local context to develop/ update national policies and programs.

Infection prevention and control risk factors in health workers infected with SARS-CoV-2 in Jordan: A case control study.

BACKGROUND: Despite under-reporting, health workers (HWs) accounted for 2 to 30% of the reported COVID-19 cases worldwide. In line with data from other countries, Jordan recorded multiple case surges among HWs. METHODS: Based on the standardized WHO UNITY case-control study protocol on assessing risk factors for SARS-CoV-2 infection in HWs, HWs with confirmed COVID-19 were recruited as cases from eight hospitals in Jordan. HWs exposed to COVID-19 patients in the same setting but without infection were recruited as controls. The study lasted approximately two months (from early January to early March 2021). Regression models were used to analyse exposure risk factors for SARS-CoV-2 infection in HWs; conditional logistic regressions were utilized to estimate odds ratios (ORs) adjusted for the confounding variables. RESULTS: A total of 358 (102 cases and 256 controls) participants were included in the analysis. The multivariate analysis showed that being exposed to COVID-19 patients within 1 metre for more than 15 minutes increased three-fold the odds of infection (OR 2.92, 95% CI 1.25-6.86). Following IPC standard precautions when in contact with patients was a significant protective factor. The multivariate analysis showed that suboptimal adherence to hand hygiene increased the odds of infection by three times (OR 3.18; 95% CI 1.25-8.08). CONCLUSION: Study findings confirmed the role of hand hygiene as one of the most cost-effective measures to combat the spreading of viral infections. Future studies based on the same protocol will enable additional interpretations and confirmation of the Jordan experience.

WHO's support for COVID-19 research and knowledge management in the Eastern Mediterranean Region.

Health research, innovation and knowledge management remain major priorities of the WHO's response to the COVID-19 pandemic. WHO's Eastern Mediterranean Regional Office (EMRO) supports priority research initiatives that address gaps in current knowledge regarding the COVID-19 pandemic. Through a specific call for proposals, 122 research proposals were received and reviewed in 2020, of which 17 were recommended for funding from eight countries. Ten countries in the region participated in the global solidarity trial to assess potential therapies for COVID-19. In addition, WHO advocated for early serological and epidemiological investigations ('COVID-19 Unity Studies') on the general population, healthcare workers, pregnant women and neonates, and extending technical, financial and material support for them.Starting in early 2020, scholarly articles on COVID-19 have been published in every issue of the Eastern Mediterranean Health Journal More than 6300 publications on COVID-19 were made available on the WHO knowledge management portal in the last year alone. WHO is also supporting countries in conducting studies to assess the field effectiveness of vaccines deployed nationally. To build and strengthen country capacities, regional webinars and intercountry meetings were conducted on research ethics, national health information systems and evidence-based health policy making. With support from WHO EMRO's new research and knowledge management pillar, countries in the region were well equipped to contribute to a global understanding of the novel virus's characteristics, as well as employ a national response based on informed evidence.

Transmission of SARS-CoV-2 in standardised first few X cases and household transmission investigations: A systematic review and meta-analysis.

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 >99% 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.

Epidemiological modelling in refugee and internally displaced people settlements: challenges and ways forward.

The spread of infectious diseases such as COVID-19 presents many challenges to healthcare systems and infrastructures across the world, exacerbating inequalities and leaving the world's most vulnerable populations at risk. Epidemiological modelling is vital to guiding evidence-informed or data-driven decision making. In forced displacement contexts, and in particular refugee and internally displaced people (IDP) settlements, it meets several challenges including data availability and quality, the applicability of existing models to those contexts, the accurate modelling of cultural differences or specificities of those operational settings, the communication of results and uncertainties, as well as the alignment of strategic goals between diverse partners in complex situations. In this paper, we systematically review the limited epidemiological modelling work applied to refugee and IDP settlements so far, and discuss challenges and identify lessons learnt from the process. With the likelihood of disease outbreaks expected to increase in the future as more people are displaced due to conflict and climate change, we call for the development of more approaches and models specifically designed to include the unique features and populations of refugee and IDP settlements. To strengthen collaboration between the modelling and the humanitarian public health communities, we propose a roadmap to encourage the development of systems and frameworks to share needs, build tools and coordinate responses in an efficient and scalable manner, both for this pandemic and for future outbreaks.

SARS-CoV-2 seroprevalence in Aden, Yemen: a population-based study.

BACKGROUND: In Yemen, initial surveillance of coronavirus disease 2019 (COVID-19) focused primarily on patients with symptoms or severe disease. The full spectrum of the disease remains unclear. To the best of the authors' knowledge, this is the first seroprevalence study performed in Yemen. METHODS: This cross-sectional investigation included 2001 participants from all age groups from four districts in Aden, southern Yemen. A multi-stage sampling method was used. Data were collected using a well-structured questionnaire, and blood samples were taken. Healgen COVID-19 IgG/IgM Rapid Diagnostic Test (RDT) Cassettes were used in all participants. All positive RDTs and 14% of negative RDTs underwent enzyme-linked immunosorbent assay (ELISA) testing (WANTAI SARS-CoV-2 Ab ELISA Kit) for confirmation. RESULTS: In total, 549 of 2001 participants were RDT positive and confirmed by ELISA, giving a prevalence of COVID-19 of 27.4%. The prevalence of immunoglobulin G was 25%. The prevalence of asymptomatic COVID-19 in the entire study group was 7.9%. The highest prevalence was observed in Al-Mansurah district (33.4%). Regarding sociodemographic factors, the prevalence of COVID-19 was significantly higher among females, housewives and subjects with a history of contact with a COVID-19 patient: 32%, 31% and 39%, respectively. CONCLUSION: This study found high prevalence of COVID-19 in the study population. Household transmission was common.

Early epidemiological investigations: World Health Organization UNITY protocols provide a standardized and timely international investigation framework during the COVID-19 pandemic.

BACKGROUND: The declaration of Coronavirus disease 2019 (COVID-19) as a Public Health Emergency of International Concern (PHEIC) on 30 January 2020 required rapid implementation of early investigations to inform appropriate national and global public health actions. METHODS: The suite of existing pandemic preparedness generic epidemiological early investigation protocols was rapidly adapted for COVID-19, branded the 'UNITY studies' and promoted globally for the implementation of standardized and quality studies. Ten protocols were developed investigating household (HH) transmission, the first few cases (FFX), population seroprevalence (SEROPREV), health facilities transmission (n = 2), vaccine effectiveness (n = 2), pregnancy outcomes and transmission, school transmission, and surface contamination. Implementation was supported by WHO and its partners globally, with emphasis to support building surveillance and research capacities in low- and middle-income countries (LMIC). RESULTS: WHO generic protocols were rapidly developed and published on the WHO website, 5/10 protocols within the first 3 months of the response. As of 30 June 2021, 172 investigations were implemented by 97 countries, of which 62 (64%) were LMIC. The majority of countries implemented population seroprevalence (71 countries) and first few cases/household transmission (37 countries) studies. CONCLUSION: The widespread adoption of UNITY protocols across all WHO regions indicates that they addressed subnational and national needs to support local public health decision-making to prevent and control the pandemic.

COVID-19 in the Gulf Cooperation Council Member States: An Evidence of Effective Response.

OBJECTIVES: The World Health Organization (WHO) published a global strategic response plan in February 2020 aiming to mitigate the impact of the novel coronavirus disease 2019 (COVID-19) outbreak. It identified immediate activities required for global preparedness and response to the outbreak and set eight priority areas (pillars) essential for scaling up countries' operational readiness and response. Despite a semi-annual progress report on implementing the Global Strategic Plan in June 2020, there is limited granular information available on the extent of the national plan's content and implementation, particularly in the Member States of the Gulf Cooperation Council (GCC). Therefore, we sought to review the preparedness and responsiveness towards the COVID-19 outbreak in the GCC in the first phase of the pandemic and to document lessons learned for improving the ongoing response efforts and preparedness for future pandemics. METHODS: A rapid appraisal was conducted in June 2020 according to the WHO Strategic Preparedness and Response Plan and the accompanying Operational Planning Guidelines. The survey was administered to public health professionals or/and infectious disease experts in the states. The findings were cross-triangulated with secondary data that was publicly available for each country. RESULTS: The preparedness and response efforts of Bahrain, Saudi Arabia, and the UAE were fully compliant with all 11 (100%) pillars of the modified strategic response measures. Kuwait, Oman, and Qatar complied with eight of the pillars. The component on conducting COVID-19 related research was the lowest-performing across all the six states. CONCLUSIONS: All GCC states demonstrated an effective response to the pandemic, enhanced existing infrastructures, and accelerated reforms that would have otherwise taken longer. The lessons learned through the early phase of the pandemic continue to steer the states in realigning their strategies and resetting their goals of controlling the outbreak, particularly in the current context of vaccine introduction and increasing preparedness capacities for future pandemics.

A participatory modelling approach for investigating the spread of COVID-19 in countries of the Eastern Mediterranean Region to support public health decision-making.

Early on in the COVID-19 pandemic, the WHO Eastern Mediterranean Regional Office recognised the importance of epidemiological modelling to forecast the progression of the COVID-19 pandemic to support decisions guiding the implementation of response measures. We established a modelling support team to facilitate the application of epidemiological modelling analyses in the Eastern Mediterranean Region (EMR) countries. Here, we present an innovative, stepwise approach to participatory modelling of the COVID-19 pandemic that engaged decision-makers and public health professionals from countries throughout all stages of the modelling process. Our approach consisted of first identifying the relevant policy questions, collecting country-specific data and interpreting model findings from a decision-maker's perspective, as well as communicating model uncertainty. We used a simple modelling methodology that was adaptable to the shortage of epidemiological data, and the limited modelling capacity, in our region. We discuss the benefits of using models to produce rapid decision-making guidance for COVID-19 control in the WHO EMR, as well as challenges that we have experienced regarding conveying uncertainty associated with model results, synthesising and comparing results across multiple modelling approaches, and modelling fragile and conflict-affected states.