Background As vaccine roll-out continues across the globe as part of the efforts to protect humanity against SARS-CoV-2, concerns are increasingly shifting to the duration of vaccine-induced immunity. Responses to these concerns are critical in determining if, when, and who will need booster doses following full vaccination against SARS-CoV-2. However, synthesised studies about the durability of vaccine-induced immunity against SARS-CoV-2 are scarce. This systematic review synthesised available global evidence on the duration of immunity following full vaccination against SARS-CoV-2. Methods We searched through Psych Info, Web of Science, Scopus, Google Scholar, PubMed, and WHO COVID-19 databases for relevant studies published before December 2021. Five eligibility criteria were used in scrutinising studies for inclusion. The quality of the included studies was assessed based on Joana Briggs Institute’s (JBI) Critical Appraisal tool and Cochrane’s Risk of Bias tool—version 2 (RoB 2), while the reporting of the results was guided by the Synthesis Without Meta-analysis (SWiM) guidelines. Results Twenty-seven out of the 666 identified studies met the inclusion criteria. The findings showed that vaccine-induced protection against SARS-CoV-2 infections builds rapidly after the first dose of vaccines and peaks within 4 to 42 days after the second dose, before waning begins in subsequent months, typically from 3 to 24 weeks. Vaccine-induced antibody response levels varied across different demographic and population characteristics and were higher in people who reported no underlying health conditions compared to those with immunosuppressed conditions. Conclusions Waning of immunity against SARS-CoV-2 begins as early as the first month after full vaccination and this decline continues till the sixth month when the level of immunity may not be able to provide adequate protection against SARS-CoV-2. While the evidence synthesised in this review could effectively inform and shape vaccine policies regarding the administration of booster doses, more evidence, especially clinical trials, are still needed to ascertain, with greater precision, the exact duration of immunity offered by different vaccine types, across diverse population characteristics, and in different vulnerability parameters. Registration The protocol for this review was pre-registered with the International Prospective Register of Systematic Reviews [PROSPERO] (Registration ID: CRD420212818).

Stochastic dynamics involved in ecological count data require distribution fitting procedures to model and make informed judgments. The study provides empirical research, focused on the provision of an early warning system and a spatial graph that can detect societal fire risks. It offers an opportunity for communities, organizations, risk managers, actuaries and governments to be aware of, and understand fire risks, so that they will increase the direct tackling of the threats posed by fire. Statistical distribution fitting method that best helps identify the stochastic dynamics of fire count data is used. The aim is to provide a fire-prediction model and fire spatial graph for observed fire count data. An empirical probability distribution model is fitted to the fire count data and compared to the theoretical probability distribution of the stochastic process of fire count data. The distribution fitted to the fire frequency count data helps identify the class of models that are exhibited by the fire and provides time leading decisions. The research suggests that fire frequency and loss (fire fatalities) count data in Ghana are best modelled with a Negative Binomial Distribution. The spatial map of observed fire frequency and fatality measured over 5 years (2007–2011) offers in this study a first regional assessment of fire frequency and fire fatality in Ghana.

BackgroundEmerging evidence in both developed and developing countries indicate that occupational health hazards and diseases among construction workers constitute a significant public health challenge. While occupational health hazards and conditions in the construction sector are diverse, a burgeoning body of knowledge is emerging about respiratory health hazards and diseases. Yet, there is a notable gap in the existing literature in terms of comprehensive syntheses of the available evidence on this topic. In light of this research gap, this study systematically reviewed the global evidence on occupational health hazards and related respiratory health conditions among construction workers.MethodsUsing meta-aggregation, guided by the Condition (respiratory health conditions), Context (construction industry) and Population (construction workers) (CoCoPop) framework and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, literature searches were conducted on Scopus, PubMed, Web of Science and Google Scholar for relevant studies on respiratory health conditions affecting construction workers. Four eligibility criteria were used in scrutinising studies for inclusion. The quality of the included studies was assessed based on Joanna Briggs Institute’s Critical Appraisal tool, while the reporting of the results was guided by the Synthesis Without Meta-analysis guidelines.ResultsFrom an initial pool of 256 studies from the various databases, 25 studies published between 2012 and October 2022 were identified as meeting the inclusion criteria. In all, 16 respiratory health conditions were identified, with cough (ie, dry and with phlegm), dyspnoea/breathlessness and asthma emerging as the top three respiratory conditions among construction workers. The study identified six overarching themes of hazards that are associated with respiratory health conditions among construction workers. These hazards include exposure to dust, respirable crystalline silica, fumes, vapours, asbestos fibres and gases. Smoking and extended period of exposure to the respiratory hazard were found to increase the risk of contracting respiratory diseases.ConclusionsOur systematic review indicates that construction workers are exposed to hazards and conditions that have adverse effects on their health and well-being. Given the considerable impact that work-related health hazards can have on the health and socioeconomic well-being of construction workers, we suggest that the implementation of a comprehensive occupational health programme is essential. Such a programme would extend beyond the mere provision of personal protective equipment and would incorporate a range of proactive measures aimed at controlling the hazards and mitigating the risk of exposure to the occupational health hazards.

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