Differential protection against SARS-CoV-2 reinfection pre- and post-Omicron

Nature, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 5, 2025

Abstract The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly evolved over short timescales, leading to the emergence of more transmissible variants such as Alpha and Delta 1–3 . arrival Omicron variant marked a major shift, introducing numerous extra mutations in spike gene compared with earlier 1,2 These evolutionary changes have raised concerns regarding their potential impact on immune evasion, disease severity effectiveness vaccines treatments 1,3 In this epidemiological study, we identified two distinct patterns protective effect natural infection against reinfection versus pre-Omicron eras. Before Omicron, provided strong durable protection reinfection, minimal waning time. However, during era, was robust only for those recently infected, declining time diminishing within year. results demonstrate that SARS-CoV-2 is shaped by dynamic interaction between host immunity viral evolution, contrasting before after Omicron’s first wave. This shift suggests change pressures, intrinsic transmissibility driving adaptation escape becoming dominant post-Omicron, underscoring need periodic vaccine updates sustain immunity.

Language: Английский

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Short- and longer-term all-cause mortality among SARS-CoV-2- infected individuals and the pull-forward phenomenon in Qatar: a national cohort study

International Journal of Infectious Diseases, Journal Year: 2023, Volume and Issue: 136, P. 81 - 90

Published: Sept. 16, 2023

We assessed short-, medium-, and long-term all-cause mortality risks after a primary SARS-CoV-2 infection.A national, matched, retrospective cohort study was conducted in Qatar to assess risk of the national infection compared with infection-naïve cohort. Associations were estimated using Cox proportional-hazards regression models. Analyses stratified by vaccination status clinical vulnerability status.Among unvaccinated persons, within 90 days infection, adjusted hazard ratio (aHR) comparing incidence primary-infection 1.19 (95% confidence interval 1.02-1.39). aHR 1.34 (1.11-1.63) persons more clinically vulnerable severe COVID-19 0.94 (0.72-1.24) those less vulnerable. Beyond 0.50 (0.37-0.68); 0.41 (0.28-0.58) at 3-7 months 0.76 (0.46-1.26) ≥8 months. The 0.37 (0.25-0.54) 0.77 (0.48-1.24) persons. Among vaccinated comparable versus cohorts, regardless status.COVID-19 primarily driven an accelerated onset death among individuals who already mortality, but prevented these deaths.

Language: Английский

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Prevalence of hepatitis B and C viruses among migrant workers in Qatar

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: May 17, 2024

Abstract Limited data exist on viral hepatitis among migrant populations. This study investigated the prevalence of current B virus (HBV) infection and lifetime C (HCV) Qatar's craft manual workers (CMWs), constituting 60% country's population. Sera collected during a nationwide COVID-19 population-based cross-sectional survey CMWs between July 26 September 9, 2020, underwent testing for HBsAg HCV antibodies. Reactive samples confirmatory testing, logistic regression analyses were employed to explore associations with HBV infections. Among 2528 specimens tested infection, 15 reactive, 8 subsequently confirmed positive. Three lacked sufficient sera but included in analysis through multiple imputations. Prevalence was 0.4% (95% CI 0.2–0.7%). Educational attainment occupation significantly associated infection. For out 2607 tested, 46 23 0.8% 0.5–1.2%). Egyptians exhibited highest at 6.5% 3.1–13.1%), followed by Pakistanis 3.1% 1.1–8.0%). Nationality, geographic location, is relatively low CMWs, while falls within intermediate range, both compared global regional levels.

Language: Английский

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Motorcycle-related crashes before and during the COVID-19 pandemic: A comparative retrospective observational study from the Middle East

Injury, Journal Year: 2024, Volume and Issue: 55(3), P. 111343 - 111343

Published: Jan. 21, 2024

Language: Английский

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Effectiveness of two and three doses of COVID-19 mRNA vaccines against infection, symptoms, and severity in the pre-omicron era: A time-dependent gradient

Vaccine, Journal Year: 2024, Volume and Issue: 42(14), P. 3307 - 3320

Published: April 14, 2024

Vaccines were developed and deployed to combat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This study aimed characterize patterns in the protection provided by BNT162b2 mRNA-1273 mRNA vaccines against a spectrum of SARS-CoV-2 infection symptoms severities. A national, matched, test-negative, case-control was conducted Qatar between January 1 December 18, 2021, utilizing sample 238,896 PCR-positive tests 6,533,739 PCR-negative tests. Vaccine effectiveness estimated asymptomatic, symptomatic, disease 2019 (COVID-19), critical COVID-19, fatal COVID-19 infections. Data sources included Qatar's national databases for laboratory testing, vaccination, hospitalization, death. Effectiveness two-dose vaccination 75.6% (95% CI: 73.6–77.5) asymptomatic 76.5% 75.1–77.9) symptomatic each severe, critical, infections surpassed 90%. Immediately after second dose, all categories—namely, COVID-19—exhibited similarly high effectiveness. However, from 181 270 days post-second declined below 40%, while remained consistently high. estimates often had wide 95% confidence intervals. Analogous observed three-dose two- vaccination. Sensitivity analyses confirmed results. gradient vaccine exists is linked severity infection, providing higher more cases. intensifies over time as immunity wanes last dose. These appear consistent irrespective type or whether involves primary series booster.

Language: Английский

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

EClinicalMedicine, Journal Year: 2023, Volume and Issue: 62, P. 102102 - 102102

Published: July 20, 2023

Waning of natural infection protection and vaccine highlight the need to evaluate changes in population immunity over time. Population previous SARS-CoV-2 or COVID-19 vaccination are defined, respectively, as overall against reinfection breakthrough at a given point time population.

Language: Английский

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

Frontiers in Medicine, Journal Year: 2024, Volume and Issue: 11

Published: March 11, 2024

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

Language: Английский

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History of primary-series and booster vaccination and protection against Omicron reinfection

Science Advances, Journal Year: 2023, Volume and Issue: 9(40)

Published: Oct. 4, 2023

Laboratory evidence suggests a possibility of immune imprinting for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We investigated the differences in incidence SARS-CoV-2 reinfection cohort persons who had primary Omicron infection, but different vaccination histories using matched, national, retrospective, studies. Adjusted hazard ratio incidence, factoring adjustment testing rate, was 0.43 [95% confidence interval (CI): 0.39 to 0.49] comparing history two-dose no vaccination, 1.47 (95% CI: 1.23 1.76) three-dose and 0.57 0.48 0.68) vaccination. Divergence cumulative curves increased markedly when dominated by BA.4/BA.5 BA.2.75* subvariants. The primary-series enhanced protection against reinfection, booster compromised reinfection. These findings do not undermine public health utility

Language: Английский

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Evaluating Hospital Admission Data as Indicators of COVID-19 Severity: A National Assessment in Qatar

Open Forum Infectious Diseases, Journal Year: 2025, Volume and Issue: 12(3)

Published: Feb. 17, 2025

Abstract Background Accurately assessing SARS-CoV-2 infection severity is essential for understanding the health impact of and evaluating effectiveness interventions. This study investigated whether SARS-CoV-2–associated hospitalizations can reliably measure true COVID-19 severity. Methods The diagnostic accuracy acute care ICU as indicators was assessed in Qatar from 6 September 2021 to 13 May 2024. WHO criteria severe, critical, fatal served reference standard. Two were assessed: (1) any hospitalization or beds (2) ICU-only hospitalizations. Results A total 644 176 infections analyzed. percent agreement between (acute ICU) 98.7% (95% confidence interval (CI), 98.6–98.7); however, Cohen's kappa only 0.17 CI, 0.16–0.18), indicating poor agreement. Sensitivity, specificity, PPV, negative predictive value 100% 99.6–100), 98.6–98.7), 9.7% 9.1–10.3), 100–100), respectively. For hospitalizations, 99.8% 99.8–99.9), with a 0.47 0.44–0.50), fair-to-good 46.6% 43.4–49.9), 99.9% 99.9–99.9), 47.9% 44.6–51.2), Conclusions Generic hospital admissions are unreliable severity, whereas somewhat more accurate. findings demonstrate importance applying specific, robust criteria—such criteria—to reduce bias epidemiological vaccine studies.

Language: Английский

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Protection conferred by SARS-CoV-2 infection across a spectrum of reinfection symptoms and severities

BMJ Open Respiratory Research, Journal Year: 2025, Volume and Issue: 12(1), P. e002718 - e002718

Published: March 1, 2025

Background SARS-CoV-2 infection is associated with protection against reinfection. This study analysed this across different reinfection symptoms and severities, comparing the preomicron omicron eras. Methods A nationwide, matched, test-negative, case–control was conducted in Qatar from 5 February 2020 to 12 March 2024. The analysis used a sample of 509 949 positive 8 494 782 negative tests, while included 682 257 6 904 044 tests. Data were sourced Qatar’s national databases for COVID-19 laboratory testing, vaccination, hospitalisation death. Results Effectiveness estimated at 80.9% (95% CI: 79.1% 82.6%) asymptomatic reinfection, 87.5% 86.1% 88.9%) symptomatic 97.8% 95.7% 98.9%) severe 100.0% 97.5% 100.0%) critical 88.1% 50.3% 97.2%) fatal For estimates 46.4% 36.9% 54.4%) 52.8% 44.4% 60.0%) 55.4% 15.1% 75.2% −58.8% 97.5%) over time since previous showed no discernible decline all forms era, but rapid reinfections era. Conclusions gradient evident, highest observed COVID-19. Over time, becomes more pronounced, as decreases, outcomes remains strong.

Language: Английский

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