Short- and longer-term all-cause mortality among SARS-CoV-2-infected persons and the pull-forward phenomenon in Qatar

Abstract

Background: Risk of short- and long-term all-cause mortality after a primary SARS-CoV-2 infection is inadequately understood. Methods: A national, matched, retrospective cohort study was conducted in Qatar to assess the risk of all-cause mortality in the national cohort of people infected with SARS-CoV-2 compared with a reference national control cohort of uninfected persons. Associations were estimated using Cox proportional-hazards regression models. Results: Among unvaccinated persons, within 90 days after primary infection, adjusted hazard ratio (aHR) comparing incidence of death in the primary-infection cohort with the infection-naive cohort was 1.19 (95% CI: 1.02-1.39). The aHR was 1.34 (95% CI: 1.11-1.63) in persons more clinically vulnerable to severe COVID-19 and 0.94 (95% CI: 0.72-1.24) in those less clinically vulnerable to severe COVID-19. In subsequent follow-up, the aHR was 0.50 (95% CI: 0.37-0.68). The aHR was 0.41 (95% CI: 0.28-0.58) in months 3-7 after the primary infection and 0.76 (95% CI: 0.46-1.26) in subsequent months. The aHR was 0.37 (95% CI: 0.25-0.54) in persons more clinically vulnerable to severe COVID-19 and 0.77 (95% CI: 0.48-1.24) in those less clinically vulnerable to severe COVID-19. Among vaccinated persons, no evidence was found for differences in incidence of death in the primary-infection versus infection-naive cohorts, even among persons more clinically vulnerable to severe COVID-19. Conclusions: COVID-19 mortality in Qatar appears primarily driven by forward displacement of deaths of individuals with relatively short life expectancy and more clinically vulnerable to severe COVID-19. Vaccination negated the mortality displacement by preventing early deaths.

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

“…1,2 Findings are also consistent with accelerated deaths among older adults and those with coexisting conditions being a major driver of COVID-19 mortality in Qatar. 17 These findings may also suggest that, specifically among older individuals, the effect of age on severe COVID-19 could outweigh the effect of coexisting conditions. The findings also support the concept of COVID-19 being an emerging typical aging disease.…”

“…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.…”

“…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.…”

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

Population immunity of natural infection, primary-series vaccination, and booster vaccination in Qatar during the COVID-19 pandemic: An observational study

“…23 Detailed descriptions of Qatar's population and of the national databases have been reported previously. 3,9,10,14,19,24…”