Societal health and economic burden of cardiovascular diseases in the population with type 2 diabetes in Qatar. A 10-year forecasting model.

AIMS: To predict the future health and economic burden of cardiovascular disease (CVD) in type 2 diabetes (T2D) in Qatar. MATERIALS AND METHODS: A dynamic multistate model was designed to simulate the progression of fatal and non-fatal CVD events among people with T2D in Qatar aged 40-79 years. First CVD events [i.e. myocardial infarction (MI) and stroke] were calculated via the 2013 Pooled Cohort Equation, while recurrent CVD events were sourced from the REACH registry. Key model outcomes were fatal and non-fatal MI and stroke, years of life lived, quality-adjusted life years, total direct medical costs and total productivity loss costs. Utility and cost model inputs were drawn from published sources. The model adopted a Qatari societal perspective. Sensitivity analyses were performed to test the robustness of estimates. RESULTS: Over 10 years among people with T2D, model estimates 108 195 [95% uncertainty interval (UI) 104 249-112 172] non-fatal MIs, 62 366 (95% UI 60 283-65 520) non-fatal strokes and 14 612 (95% UI 14 472-14 744) CVD deaths. The T2D population accrued 4 786 605 (95% UI 4 743 454, 4 858 705) total years of life lived and 3 781 833 (95% UI 3 724 718-3 830 669) total quality-adjusted life years. Direct costs accounted for 57.85% of the total costs, with a projection of QAR41.60 billion (US$11.40 billion) [95% UI 7.53-147.40 billion (US$2.06-40.38 billion)], while the total indirect costs were expected to exceed QAR30.31 billion (US$8.30 billion) [95% UI 1.07-162.60 billion (US$292.05 million-44.55 billion)]. CONCLUSIONS: The findings suggest a significant economic and health burden of CVD among people with T2D in Qatar and highlight the need for more enhanced preventive strategies targeting this population group.

COVID-19 testing, incidence, and positivity trends among school age children during the academic years 2020-2022 in the State of Qatar: special focus on using CDC indicators for community transmission to evaluate school attendance policies and public health response.

BACKGROUND: There exists a gap in our understanding of the age-dependent epidemiological dynamics of SARS-CoV-2 among school-age children in comparison to adults within the State of Qatar. Additionally, there has been limited assessment of the timely implementation of physical distancing interventions, notably national school closures, and their impact on infection trends. METHODS: We used the national database to capture all records of polymerase-chain-reaction (PCR) testing, and rapid antigen tests (RAT) conducted at all health care venues in Qatar and administered between August 26, 2020, and August 21, 2022, across all age groups (≥ 5 years old). Study participants under 18 years old were categorized into two age brackets: (5-11) and (12-17), aligning with the Primary and Preparatory/Secondary grade levels in Qatar, respectively. We assessed age group testing rates, incidence rates, and positivity rates in relation to adults. These epidemiological metrics were compared with the CDC's thresholds for COVID-19 community transmission. RESULTS: Throughout the school years of 2020-2021 and 2021-2022, a total of 5,063,405 and 6,130,531 tests were respectively conducted. In the 2020-2021 school year, 89.6% of the tests were administered to adults, while 13.7% were conducted on children in the following year. The overall test positivity rates for the 2020-2021 and 2021-2022 school years were 5.8% and 8.1%, respectively. Adolescents underwent the fewest tests during the full study period compared to both adults and young children. Using the CDC indicators, we found that children and adolescents can significantly contribute to elevated infection rates, potentially driving community transmission upon relaxation of social restrictions. CONCLUSION: It is crucial to acknowledge the potential for higher transmission among youth and adolescents when formulating transmission control strategies and making decisions regarding school closures. Employing data-driven indicators and thresholds to monitor COVID-19 community levels is important for informing decision-making. These approaches also enable the prompt implementation of infection control transmission mitigation measures in future pandemics.

Prevalence and determinants of symptomatic COVID-19 infection among children and adolescents in Qatar: a cross-sectional analysis of 11 445 individuals.

There is a paucity of evidence about the prevalence and risk factors for symptomatic infection among children. This study aimed to describe the prevalence of symptomatic coronavirus disease 2019 (COVID-19) and its risk factors in children and adolescents aged 0-18 years in Qatar. We conducted a cross-sectional study of all children aged 0-18 years diagnosed with COVID-19 using polymerase chain reaction in Qatar during the period 1st March to 31st July 2020. A generalised linear model with a binomial family and identity link was used to assess the association between selected factors and the prevalence of symptomatic infection. A total of 11 445 children with a median age of 8 years (interquartile range (IQR) 3-13 years) were included in this study. The prevalence of symptomatic COVID-19 was 36.6% (95% confidence interval (CI) 35.7-37.5), and it was similar between children aged <5 years (37.8%), 5-9 years (34.3%) and 10 + years (37.3%). The most frequently reported symptoms among the symptomatic group were fever (73.5%), cough (34.8%), headache (23.2%) and sore throat (23.2%). Fever (82.8%) was more common in symptomatic children aged <5 years, while cough (38.7%) was more prevalent in those aged 10 years or older, compared to other age groups. Variables associated with an increased risk of symptomatic infection were; contact with confirmed cases (RD 0.21; 95% CI 0.20-0.23; P = 0.001), having visited a health care facility (RD 0.54; 95% CI 0.45-0.62; P = 0.001), and children aged under 5 years (RD 0.05; 95% CI 0.02-0.07; P = 0.001) or aged 10 years or older (RD 0.04; 95% CI 0.02-0.06; P = 0.001). A third of the children with COVID-19 were symptomatic with a higher proportion of fever in very young children and a higher proportion of cough in those between 10 and 18 years of age.

Adaptive Immune Responses in Humans During Nipah Virus Acute and Convalescent Phases of Infection.

BACKGROUND: Nipah virus (NiV) is 1 of 10 potential causes of imminent public health emergencies of international concern. We investigated the NiV outbreak that occurred in May 2018 in Kerala, India. Here we describe the longitudinal characteristics of cell-mediated and humoral immune responses to NiV infection during the acute and convalescent phases in 2 human survivors. METHODS: Serial blood samples were obtained from the only 2 survivors of the NiV outbreak in Kerala. We used flow cytometry to determine the absolute T-lymphocyte and B-lymphocyte counts and the phenotypes of both T and B cells. We also detected and quantitated the humoral immune response to NiV by virus-specific immunoglobulin M (IgM) and immunoglobulin G (IgG) enzyme-linked immunosorbent assay. RESULTS: Absolute numbers of T lymphocytes remained within normal limits throughout the period of illness studied in both survivors. However, a marked elevation of activated CD8 T cells was observed in both cases. More than 30% of total CD8 T cells expressed Ki67, indicating active proliferation. Proliferating (Ki-67+) CD8 T cells expressed high levels of granzyme B and PD-1, consistent with the profile of acute effector cells. Total B-lymphocyte, activated B-cell, and plasmablast counts were also elevated in NiV survivors. These individuals developed detectable NiV-specific IgM and IgG antibodies within a week of disease onset. Clearance of NiV RNA from blood preceded the appearance of virus-specific IgG and coincided with the peak of activated CD8 T cells. CONCLUSIONS: We describe for the first time longitudinal kinetic data on the activation status of human B- and T-cell populations during acute NiV infection. While marked CD8 T-cell activation was observed with effector characteristics, activated CD4 T cells were less prominent.

Spatial distribution of Haemaphysalis species ticks and human Kyasanur Forest Disease cases along the Western Ghats of India, 2017-2018.

Kyasanur Forest Disease (KFD) is a viral haemorrhagic fever, transmitted to humans and other hosts by a tick vector of genus Haemaphysalis. It affects 400-500 people annually in the Western Ghats region of India through spring to summer season. To understand the species composition, distribution, and abundance of Haemaphysalis ticks in endemic taluks (sub-districts) of India, a surveillance for ticks was conducted between October 2017 and January 2018. In total 105 sites were selected based on grid sampling from five taluks representing five KFD endemic states in south India. A sum of 8373 ticks were collected by using standard flagging method. The study showed a wide distribution of host seeking tick species among the selected taluks, wherein Haemaphysalis spinigera was predominant in 3/5 taluks, Haemaphysalis bispinosa in 1/5 taluks, and both the species in 1/5 taluks. Further, the H. spinigera abundance was categorised and compared with the incidence of human cases during the same season. The grids with very high and high H. spinigera abundance had 70% of the 205 human cases reported. This method of tick surveillance could be efficiently used as a standard model for KFD transmission risk assessment and prediction of impending outbreaks.

Risk Factors for Acquiring Scrub Typhus among Children in Deoria and Gorakhpur Districts, Uttar Pradesh, India, 2017.

Scrub typhus is associated with outbreaks of acute encephalitis syndrome in Uttar Pradesh, India. A case-control study indicated that children residing, playing, or visiting fields; living with firewood stored indoors; handling cattle fodder; and practicing open defecation were at increased risk for scrub typhus. Communication messages should focus on changing these behaviors.

Determining the conclusiveness of a meta-analysis.

The pursuit of conclusive evidence related to an unanswered foreground (decision-making) question has been the driving factor behind multiple ongoing and planned randomized controlled trials as well as meta-analyses. However, a fundamental challenge lies in establishing robust methods for ascertaining whether a collection of synthesized trials has yielded a definitive answer to that foreground question through the process of meta-analysis. This article explores the evolution of methods that attempt to address this challenge. These methods have primarily focused on defining and measuring the sufficiency and stability of evidence within a meta-analytic context. Cumulative meta-analysis and trial sequential analysis are the tools currently used, but they both come with limitations and challenges. We further discuss methods aimed at evaluating the evolution of effects over time more directly, such as the recursive cumulative meta-analysis. The latter method can be considered a better alternative, as it serves to demonstrate whether there is a true underlying treatment effect to which the meta-analysis is converging. However, recursive cumulative meta-analysis falls short of a specific indicator that establishes whether convergence has been reached. We coin the term exit for a meta-analysis where convergence can be demonstrated. Developing methods to determine the exit status of a meta-analysis is the next priority in research synthesis methods, as it will indicate that the research journey has concluded on a particular foreground question with no expectation of a different result with the addition of future trials.

Use of conditional estimates of effect in cancer epidemiology: An application to lung cancer treatment.

BACKGROUND: In oncology clinical trials, there is the assumption that randomization sufficiently balances confounding covariates and therefore average treatment effects are usually reported. This paper explores the wider benefits provided by conditioning on covariates for reasons other than mitigation of confounding. METHODS: We reanalyzed the data from primary randomized controlled trials listed in two meta-analyses to explore the significance of conditioning on smoking status in terms of the effect magnitude of treatment on progression free survival in non-small cell lung cancer. RESULTS: The reanalysis revealed that conditioning on smoking status using sub-group analyses provided the closest empiric estimate of individual treatment effect based on smoking status and significantly reduced the heterogeneity of treatment effect observed across studies. In addition, smoking status was determined to be a modifier of the effect of treatment. CONCLUSION: Conditioning on prognostic covariates in randomized trials in oncology helps generate the closest empiric estimates of individual treatment benefit, addresses heterogeneity due to varying covariate distributions across trials and facilitates future decision making as well as evidence synthesis. Conditioning using sub-group analyses also allows examination for effect modification in meta-analysis.

Effectiveness of Pfizer-BioNTech (BNT162b2) Vaccine Among Adolescents (Aged 12-15 Years): An Observational Study in Qatar.

In May 2021, Qatar launched the BNT162b2 COVID-19 vaccine campaign for adolescents aged 12 to 15 years across all 27 health centers. Our study assessed the safety and efficacy of the vaccine among vaccinated and nonvaccinated adolescents in Qatar. Using a retrospective observational study, we analyzed the medical records of 1956 adolescents who were severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive from June 17 to December 17, 2021. The mean age for the vaccinated group was 13.89 ± 0.93 years, and for the nonvaccinated group, it was 12.99 ± 0.93 years. In the vaccinated group, 46% were male (n = 185) compared with 53% in the nonvaccinated group (n = 827) and 54% were female in the vaccinated group (n = 217) versus 47% in the nonvaccinated group (n = 727). Our findings demonstrate satisfactory protection provided by the Pfizer-BioNTech COVID-19 vaccine, with only one fifth of the study population contracting SARS-CoV-2 infections after the double-dose regimen. These results highlight the importance of maximizing vaccination coverage and considering booster doses for adolescents to enhance protection.

Short-term side effects of BNT162b2 vaccine in primary care settings in Qatar: a retrospective study.

Background: Despite the established effectiveness of the BNT162b2 Vaccine, the novel technology demands careful safety monitoring. While global studies have explored its safety, local data remains limited and exhibits some variability. This study investigated short-term side effects among BNT162b2 vaccinated individuals in Qatar. Methods: A retrospective analysis was conducted using data extracted from the electronic health records of individuals aged 18 or older across 8 primary health centers who received either the first or second dose of the BNT162b2 vaccine during the period from December 23, 2020, to April 24, 2021. The proportions of individuals experiencing short-term side effects after each dose were calculated. Logistic regression and log binomial regression analyses were used to explore associations with the side effects. Results: Among 7,764 participants, 5,489 received the first dose and 2,275 the second, with similar demographics between the groups. After the first dose, 5.5% reported at least one local side effect, compared to 3.9% after the second, with a 1.4 times higher incidence after the first dose (RR 1.4, 95% CI 1.14-1.75) compared to the second. Systemic side effects after the second dose were 2.6 times more common than after the first (RR 2.6, 95% CI 2.15-3.14). Gender, nationality, history of prior COVID-19 infection, and obesity were significantly associated with side effects after the first dose, while age, gender, and nationality, were significant factors after the second dose. Conclusion: The rates of side effects following the BNT162b2 vaccine in Qatar were relatively low, with age, gender, nationality, previous infection, and obesity identified as significant predictors. These results emphasize the need for tailored vaccination strategies and contributes valuable insights for evidence-based decision-making in ongoing and future vaccination campaigns.

Dynamics of Anti-S IgG Antibodies Titers after the Second Dose of COVID-19 Vaccines in the Manual and Craft Worker Population of Qatar.

There is limited seroepidemiological evidence on the magnitude and long-term durability of antibody titers of mRNA and non-mRNA vaccines in the Qatari population. This study was conducted to generate evidence on long-term anti-S IgG antibody titers and their dynamics in individuals who have completed a primary COVID-19 vaccination schedule. A total of 300 male participants who received any of the following vaccines BNT162b2/Comirnaty, mRNA-1273, ChAdOx1-S/Covishield, COVID-19 Vaccine Janssen/Johnson, or BBIBP-CorV or Covaxin were enrolled in our study. All sera samples were tested by chemiluminescent microparticle immunoassay (CMIA) for the quantitative determination of IgG antibodies to SARS-CoV-2, receptor-binding domain (RBD) of the S1 subunit of the spike protein of SARS-CoV-2. Antibodies against SARS-CoV-2 nucleocapsid (SARS-CoV-2 N-protein IgG) were also determined. Kaplan-Meier survival curves were used to compare the time from the last dose of the primary vaccination schedule to the time by which anti-S IgG antibody titers fell into the lowest quartile (range of values collected) for the mRNA and non-mRNA vaccines. Participants vaccinated with mRNA vaccines had higher median anti-S IgG antibody titers. Participants vaccinated with the mRNA-1273 vaccine had the highest median anti-S-antibody level of 13,720.9 AU/mL (IQR 6426.5 to 30,185.6 AU/mL) followed by BNT162b2 (median, 7570.9 AU/mL; IQR, 3757.9 to 16,577.4 AU/mL); while the median anti-S antibody titer for non-mRNA vaccinated participants was 3759.7 AU/mL (IQR, 2059.7-5693.5 AU/mL). The median time to reach the lowest quartile was 3.53 months (IQR, 2.2-4.5 months) and 7.63 months (IQR, 6.3-8.4 months) for the non-mRNA vaccine recipients and Pfizer vaccine recipients, respectively. However, more than 50% of the Moderna vaccine recipients did not reach the lowest quartile by the end of the follow-up period. This evidence on anti-S IgG antibody titers should be considered for informing decisions on the durability of the neutralizing activity and thus protection against infection after the full course of primary vaccination in individuals receiving different type (mRNA verus non-mRNA) vaccines and those with natural infection.

Redefining effect modification.

The odds ratio (OR) has been misunderstood in evidence based medicine and clinical epidemiology. Currently, "noncollapsibility" is considered a problem with interpretation of the OR and it is thought that the OR is rarely the parameter of interest for causal inference or interpretation of effect modification. The current focus on the relative risk (RR) and risk difference (RD) suffers from an important limitation: they are not solely measures of effect and vary numerically with baseline risk. In this paper, generalized linear models are examined in terms of the three binary effect measures commonly used in epidemiology to demonstrate that ORs may be the only way to interpret effect modification and have properties that should make them the parameter of interest for causal inference. We look forward to discussion, debate, and counter-views on this issue from the epidemiology community.

Cardiovascular Risks and Outcome in COVID-19 Positive Patients With Cardiovascular Disease Attending Primary Health Care Corporation in Qatar: A Retrospective Cohort Study.

Background: Coronavirus disease (COVID-19) patients with cardiovascular disease (CVD) are at a higher risk of morbidity and mortality. This study describes the risks and outcome in COVID-19 patients with CVD attending Primary Health Care Corporationsettings in Qatar. Objective: To report whether CVD increases the risk for hospitalization and further complications in COVID-19 patients. Methods: Retrospective cohort study. Results: A total of 10,178 CVD patients' data who tested positive for COVID-19 were extracted from electronic medical records on the basis of inclusion criteria and analyzed during the period of February 1, 2020 to December 31, 2020 (11 months). Among the patients included in the study, 64% (n=6527) were men and 36% (n=3651) were women; 23% (n=2299) were Qataris and 77% (n=7879) were non-Qataris. Among the selected age group of greater than 25 to less than 75 years, the median age was 50.83 years. More than half of the patients had diabetes (69.6%; n=7086) followed by hypertension (68.4%; n=6965) and dyslipidemia (45.1%; n=4590). Other comorbidities were obesity (18.3%; n=1862), kidney disease (6.5%; n=659), hematologic problems (4.2%; n=425), liver disorders (1.4%; n=142), rheumatic heart disease (1.3%; n=131) and neurologic symptoms (1.3%; n=128). Multivariate analysis for factors associated with inpatient admissions in last 28 days for patients with CVD reported that patients with age greater than 70 years are 2.8 (1.86-4.18) times higher risk of hospital admission as compared with the patients 25-30 years of age. Conclusion: The pre-existing CVD with age and other comorbidities predict the risk for hospitalization and further complications in patients with COVID-19. Further studies are needed to investigate the data from primary and secondary care about the long-term cardiovascular outcomes of patients who have survived COVID-19.

Impact of Smoking on COVID-19 Symptoms in Non-Vaccinated Patients: A Matched Observational Study from Qatar.

Purpose: Predisposition to acute illness from COVID-19 is suggested to correlate with cigarette smoking as it augments the risk of developing cardiovascular and respiratory illnesses, including infections. However, the effects of smoking on COVID-19 symptoms are not well described and controversial. In this study, we aim to explore the associations between smoking and COVID-19 symptoms. Subjects and Methods: A cross-sectional study using the Ministry of Public Health (MoPH), Qatar database was administered to a Qatari population with confirmed COVID-19 disease who filled in pre-defined phone-call questionnaire between 27th February 2020 and 31st December 2020. We analyzed 11,701 non-vaccinated COVID-19 individuals (2952 smokers and 8749 non-smokers) with confirmed RT-PCR test results. The association of smoking and the presence of symptoms as well as patient characteristics was calculated using Pearson's Chi-square and Fisher's exact tests, adjusting for potential covariates. Results: Compared with the non-smokers, symptomatic COVID-19 infection is significantly higher in smokers. In addition, we found fever as the most common symptom developed in COVID-19 patients followed by cough, headache, muscle ache, and sore throat. As compared to other symptoms, association of smoking with chills and abdominal pain was less evident (P < 0.05 and P < 0.001, respectively). However, both groups showed similar rates of developing cough. Conclusion: In conclusion, smoking is associated with COVID-19 symptoms frequency in non-vaccinated patients; nevertheless, further investigations are necessary to understand the mechanism of this association which could generate new targets for the management of COVID-19 in smoker patients.

Duration of COVID-19 mRNA Vaccine Effectiveness against Severe Disease.

Waning immunity following administration of mRNA-based COVID-19 vaccines remains a concern for many health systems. We undertook a study to determine if recent reports of waning for severe disease could have been attributed to design-related bias by conducting a study only among those detected with a first SARS-CoV-2 infection. We used a matched case-control study design with the study base being all individuals with first infection with SARS-CoV-2 reported in the State of Qatar between 1 January 2021 and 20 February 2022. Cases were those detected with first SARS-CoV-2 infection requiring intensive care (hard outcome), while controls were those detected with first SARS-CoV-2 infection who recovered without the need for intensive care. Cases and controls were matched in a 1:30 ratio for the calendar month of infection and the comorbidity category. Duration and magnitude of conditional vaccine effectiveness against requiring intensive care and the number needed to vaccinate (NNV) to prevent one more case of COVID-19 requiring intensive care was estimated for the mRNA (BNT162b2/mRNA-1273) vaccines. Conditional vaccine effectiveness against requiring intensive care was 59% (95% confidence interval (CI), 50 to 76) between the first and second dose, and strengthened to 89% (95% CI, 85 to 92) between the second dose and 4 months post the second dose in persons who received a primary course of the vaccine. There was no waning of vaccine effectiveness in the period from 4 to 6, 6 to 9, and 9 to 12 months after the second dose. This study demonstrates that, contrary to mainstream reports using hierarchical measures of effectiveness, conditional vaccine effectiveness against requiring intensive care remains robust till at least 12 months after the second dose of mRNA-based vaccines.

COVID-19 infection across workplace settings in Qatar: a comparison of COVID-19 positivity rates of screened workers from March 1st until July 31st, 2020.

INTRODUCTION: COVID-19 transmission was significant amongst Qatar's working population during the March-July 2020 outbreak. The study aimed to estimate the risk of exposure for COVID-19 across various workplace settings and demographics in the State of Qatar. METHODS: A cross-sectional study was conducted utilizing surveillance data of all workplaces with 10 or more laboratory-confirmed cases of COVID-19. These workplaces were categorized using a mapping table adapted from the North American Industry Classification System (NAICS) codes, 2017 version. The data was then analyzed to estimate and compare the positivity rate as an indicator of the risk of developing COVID-19 infection across various workplace settings in the State of Qatar. RESULTS: The highest positivity rate was reported amongst the Construction & Related (40.0%) and the Retail & Wholesale Trade sectors (40.0%), whereas, the lowest positivity rate was attributed to the healthcare workplace setting (11.0%). The highest incidence of COVID-19 infections occurred in South Asian nationalities and in the male gender. The private funded sector employees have seen higher positivity rate than employees of the governmental funded sector. CONCLUSION: The elevated risk of infection in Construction and Retail & Wholesale Trade is probably due to environmental and educational vulnerabilities. The predominant labor force of those workplace categories is South Asian craft and male manual workers. Alternatively, the better containment of the healthcare workplace setting can be attributed to the enforcement of infection control and occupational safety measures. These findings imply the importance of using preventive and surveillance strategies for high-risk workplace settings appropriately.

Prevalence of multimorbidity among adults attending primary health care centres in Qatar: A retrospective cross-sectional study.

CONTEXT: Multimorbidity (MM) is a global concern following the increase in life expectancy, the conquering of major infectious diseases, and the advances in the management of chronic illnesses. It places a substantial burden on patients and healthcare systems. AIMS: This study aims to describe the prevalence and pattern of MM in adults among primary healthcare users in Qatar. SETTINGS AND DESIGN: A retrospective cross-sectional study design. METHODS AND MATERIAL: Data were extracted from the electronic health records of patients aged 18 years and above who registered for care with 27 primary health centres in Qatar from 1st January 2017 to 30th June 2020. The distribution of MM among age groups, gender and nationality was analysed. RESULTS: In the study population of 7,96,427, the prevalence of MM was found to be 22.1%. MM was more prevalent in females (51.2%) than males (48.8%). The prevalence of MM showed an increasing trend with increasing age, with a peak of 25.8% found in the 46-55 age group. Qatari nationals accounted for 32.7% of MM, Southeast Asians for 28.3%, North Africans for 16.7% and individuals from other Middle Eastern countries for 14.1%. The five most common long-term chronic conditions were type-2 diabetes mellitus, hypertension, dyslipidaemia, obesity and eczema, with the first three being the most prevalent disease clusters. CONCLUSIONS: Our findings confirm that MM is common in Qatar's primary care centres. While the prevalence of MM was found to increase with increasing age, the largest proportion of patients with MM were those aged 46-55 years. This information adds to the available data on MM and directs health policymakers towards tailoring the management for the same.