All-cause and COVID-19 mortality in Qatar during the COVID-19 pandemic

Al-Nuaimi, Asma Ali; Chemaitelly, Hiam; Semaan, Sandy; AlMukdad, Sawsan; Al‐Kanaani, Zaina; Kaleeckal, Anvar Hassan; Latif, Ali Nizar; Al-Romaihi, Hamad Eid; Butt, Adeel A.; Al-Thani, Mohamed H.; Bertollini, Roberto; Abdulmalik, Mariam Ali; Al‐Khal, Abdullatif; Abu‐Raddad, Laith J.

doi:10.1136/bmjgh-2023-012291

Cited by 22 publications

(15 citation statements)

References 38 publications

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“…Nevertheless, mathematical modeling analyses for Qatar and their updates suggest that at least 50% of infections have never been documented. its high human development index, 53 well-resourced healthcare system, 54 and low threshold for hospital admission for older adults presenting with COVID-19, 16,19 has witnessed lower severity and fatality rates of COVID-19 than other countries. 2,16,17 While these limitations may affect some of the results relating to infection, they are less likely to affect the results relating to severe COVID-19, as severe COVID-19 cases are not likely to be undocumented and COVID-19 severity was assessed using the standardized WHO classification of COVID-19 severity, 12,13 which was applied by trained medical personnel that evaluated the severity using a national protocol applied to every hospitalized COVID-19 patient.…”

Section: Discussionmentioning

confidence: 99%

“…14,15 The national mortality database was used to obtain data on allcause mortality, including deaths occurring at healthcare facilities and elsewhere. 16,17 Qatar launched its COVID-19 vaccination program using mRNA vaccines in December of 2020, prioritizing individuals by age. 18 COVID-19 vaccination was provided free of charge regardless of citizenship or residency status.…”

Section: Study Population and Data Sourcesmentioning

confidence: 99%

“…19 Detailed descriptions of Qatar's population and national databases have been previously reported. [14][15][16][17][19][20][21]…”

Section: Study Population and Data Sourcesmentioning

confidence: 99%

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SARS‐CoV‐2 infection and effects of age, sex, comorbidity, and vaccination among older individuals: A national cohort study

Mahmoud,

Ayoub,

Coyle

et al. 2023

Influenza Resp Viruses

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BackgroundWe investigated the contribution of age, coexisting medical conditions, sex, and vaccination to incidence of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection and of severe, critical, or fatal COVID‐19 in older adults since pandemic onset.MethodsA national retrospective cohort study was conducted in the population of Qatar aged ≥50 years between February 5, 2020 and June 15, 2023. Adjusted hazard ratios (AHRs) for infection and for severe coronavirus disease 2019 (COVID‐19) outcomes were estimated through Cox regression models.ResultsCumulative incidence was 25.01% (95% confidence interval [CI]: 24.86–25.15%) for infection and 1.59% (95% CI: 1.55–1.64%) for severe, critical, or fatal COVID‐19 after a follow‐up duration of 40.9 months. Risk of infection varied minimally by age and sex but increased significantly with coexisting conditions. Risk of infection was reduced with primary‐series vaccination (AHR: 0.91, 95% CI: 0.90–0.93) and further with first booster vaccination (AHR: 0.75, 95% CI: 0.74–0.77). Risk of severe, critical, or fatal COVID‐19 increased exponentially with age and linearly with coexisting conditions. AHRs for severe, critical, or fatal COVID‐19 were 0.86 (95% CI: 0.7–0.97) for one dose, 0.15 (95% CI: 0.13–0.17) for primary‐series vaccination, and 0.11 (95% CI: 0.08–0.14) for first booster vaccination. Sensitivity analysis restricted to only Qataris yielded similar results.ConclusionIncidence of severe COVID‐19 in older adults followed a dynamic pattern shaped by infection incidence, variant severity, and population immunity. Age, sex, and coexisting conditions were strong determinants of infection severity. Vaccine protection against severe outcomes showed a dose–response relationship, highlighting the importance of booster vaccination for older adults.

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Section: Discussionmentioning

confidence: 99%

Section: Study Population and Data Sourcesmentioning

confidence: 99%

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SARS‐CoV‐2 infection and effects of age, sex, comorbidity, and vaccination among older individuals: A national cohort study

Mahmoud,

Ayoub,

Coyle

et al. 2023

Influenza Resp Viruses

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“…Qatar has young, diverse demographics; only 9% of its residents are aged 50 or above, with 89% being expatriates from over 150 countries ( 31 ). Migrant craft and manual workers constitute about 60% of the population ( 32 , 33 ), mainly single men aged 20 to 49, hailing predominantly from countries like Bangladesh, India, and Nepal, and working in development projects ( 34 ). Consequently, nationality, age, and sex serve as proxies for socio-economic status in this context ( 31 , 33 , 35 , 36 ).…”

Section: Methodsmentioning

confidence: 99%

Addressing bias in the definition of SARS-CoV-2 reinfection: implications for underestimation

Chemaitelly,

Ayoub,

Tang

et al. 2024

Front. Med.

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IntroductionReinfections are increasingly becoming a feature in the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, accurately defining reinfection poses methodological challenges. Conventionally, reinfection is defined as a positive test occurring at least 90 days after a previous infection diagnosis. Yet, this extended time window may lead to an underestimation of reinfection occurrences. This study investigated the prospect of adopting an alternative, shorter time window for defining reinfection.MethodsA longitudinal study was conducted to assess the incidence of reinfections in the total population of Qatar, from February 28, 2020 to November 20, 2023. The assessment considered a range of time windows for defining reinfection, spanning from 1 day to 180 days. Subgroup analyses comparing first versus repeat reinfections and a sensitivity analysis, focusing exclusively on individuals who underwent frequent testing, were performed.ResultsThe relationship between the number of reinfections in the population and the duration of the time window used to define reinfection revealed two distinct dynamical domains. Within the initial 15 days post-infection diagnosis, almost all positive tests for SARS-CoV-2 were attributed to the original infection. However, surpassing the 30-day post-infection threshold, nearly all positive tests were attributed to reinfections. A 40-day time window emerged as a sufficiently conservative definition for reinfection. By setting the time window at 40 days, the estimated number of reinfections in the population increased from 84,565 to 88,384, compared to the 90-day time window. The maximum observed reinfections were 6 and 4 for the 40-day and 90-day time windows, respectively. The 40-day time window was appropriate for defining reinfection, irrespective of whether it was the first, second, third, or fourth occurrence. The sensitivity analysis, confined to high testers exclusively, replicated similar patterns and results.DiscussionA 40-day time window is optimal for defining reinfection, providing an informed alternative to the conventional 90-day time window. Reinfections are prevalent, with some individuals experiencing multiple instances since the onset of the pandemic.

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“…Qatar, known for its diverse demographics with 89% of the population comprising expatriates from over 150 countries (13), has a large CMW population, constituting approximately 60% of the total population of the country. This population group, primarily consisting of unmarried men aged 20-49 years, is recruited for employment in infrastructure and development projects, including those associated with the World Cup 2022 (14)(15)(16). The majority of CMWs originate from countries where HAV infection is endemic at high incidence, and the typical age for acquiring the infection is below 10 years (12,17).…”

Section: Introductionmentioning

confidence: 99%

Prevalence of hepatitis A virus among migrant workers in Qatar: A national study

Younes,

Chemaitelly,

Nizamuddin

et al. 2024

Preprint

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Background Hepatitis A virus (HAV) is the predominant cause of acute viral hepatitis worldwide; however, data on HAV antibody prevalence (seroprevalence) among migrant populations are limited. This study aimed to investigate HAV seroprevalence among Qatar's migrant craft and manual workers (CMWs), constituting approximately 60% of the country's population. Methods HAV antibody testing was conducted on stored serum specimens obtained from CMWs during a nationwide severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) population-based cross-sectional survey between July 26 and September 9, 2020. Associations with HAV infection were investigated through regression analyses. Results Of the 2,607 specimens with HAV antibody test results, 2,393 were positive, and 214 were negative. The estimated HAV seroprevalence among CMWs was 92.0% (95% CI: 90.9-93.1%). HAV seroprevalence was generally high but exhibited some variation, ranging from 70.9% (95% CI: 62.4-78.2%) among Sri Lankans to 99.8% (95% CI: 98.2-99.9%) among Pakistanis. The multivariable regression analysis identified age, nationality, and educational attainment as statistically significant factors associated with HAV infection. Relative to CMWs aged ≤29 years, the adjusted relative risk (ARR) was 1.06 (95% CI: 1.03-1.10) in CMWs aged 30-39 years and reached 1.15 (95% CI: 1.10-1.19) in those aged ≥50 years. In comparison to Indians, the ARR was lower among Sri Lankans, assessed at 0.81 (95% CI: 0.72-0.91), but higher among Nepalese at 1.07 (95% CI: 1.04-1.11), Bangladeshis at 1.10 (95% CI: 1.07-1.13), Pakistanis at 1.12 (95% CI: 1.09-1.15), and Egyptians at 1.15 (95% CI: 1.08-1.23). No evidence for differences was found by geographic location or occupation. Conclusions HAV seroprevalence among Qatar's CMW population is very high, with over nine out of every ten individuals having been exposed to this infection, likely during childhood.

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All-cause and COVID-19 mortality in Qatar during the COVID-19 pandemic

Cited by 22 publications

References 38 publications

SARS‐CoV‐2 infection and effects of age, sex, comorbidity, and vaccination among older individuals: A national cohort study

SARS‐CoV‐2 infection and effects of age, sex, comorbidity, and vaccination among older individuals: A national cohort study

Addressing bias in the definition of SARS-CoV-2 reinfection: implications for underestimation

Prevalence of hepatitis A virus among migrant workers in Qatar: A national study

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