Effect of mRNA Vaccine Boosters against SARS-CoV-2 Omicron Infection in Qatar.

BACKGROUND: Waning of vaccine protection against coronavirus disease 2019 (Covid-19) and the emergence of the omicron (or B.1.1.529) variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have led to expedited efforts to scale up booster vaccination. Protection conferred by booster doses of the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) vaccines in Qatar, as compared with protection conferred by the two-dose primary series, is unclear. METHODS: We conducted two matched retrospective cohort studies to assess the effectiveness of booster vaccination, as compared with that of a two-dose primary series alone, against symptomatic SARS-CoV-2 infection and Covid-19-related hospitalization and death during a large wave of omicron infections from December 19, 2021, through January 26, 2022. The association of booster status with infection was estimated with the use of Cox proportional-hazards regression models. RESULTS: In a population of 2,239,193 persons who had received at least two doses of BNT162b2 or mRNA-1273 vaccine, those who had also received a booster were matched with persons who had not received a booster. Among the BNT162b2-vaccinated persons, the cumulative incidence of symptomatic omicron infection was 2.4% (95% confidence interval [CI], 2.3 to 2.5) in the booster cohort and 4.5% (95% CI, 4.3 to 4.6) in the nonbooster cohort after 35 days of follow-up. Booster effectiveness against symptomatic omicron infection, as compared with that of the primary series, was 49.4% (95% CI, 47.1 to 51.6). Booster effectiveness against Covid-19-related hospitalization and death due to omicron infection, as compared with the primary series, was 76.5% (95% CI, 55.9 to 87.5). BNT162b2 booster effectiveness against symptomatic infection with the delta (or B.1.617.2) variant, as compared with the primary series, was 86.1% (95% CI, 67.3 to 94.1). Among the mRNA-1273-vaccinated persons, the cumulative incidence of symptomatic omicron infection was 1.0% (95% CI, 0.9 to 1.2) in the booster cohort and 1.9% (95% CI, 1.8 to 2.1) in the nonbooster cohort after 35 days; booster effectiveness against symptomatic omicron infection, as compared with the primary series, was 47.3% (95% CI, 40.7 to 53.3). Few severe Covid-19 cases were noted in the mRNA-1273-vaccinated cohorts. CONCLUSIONS: The messenger RNA (mRNA) boosters were highly effective against symptomatic delta infection, but they were less effective against symptomatic omicron infection. However, with both variants, mRNA boosters led to strong protection against Covid-19-related hospitalization and death. (Funded by Weill Cornell Medicine-Qatar and others.).

Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections.

BACKGROUND: The protection conferred by natural immunity, vaccination, and both against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with the BA.1 or BA.2 sublineages of the omicron (B.1.1.529) variant is unclear. METHODS: We conducted a national, matched, test-negative, case-control study in Qatar from December 23, 2021, through February 21, 2022, to evaluate the effectiveness of vaccination with BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna), natural immunity due to previous infection with variants other than omicron, and hybrid immunity (previous infection and vaccination) against symptomatic omicron infection and against severe, critical, or fatal coronavirus disease 2019 (Covid-19). RESULTS: The effectiveness of previous infection alone against symptomatic BA.2 infection was 46.1% (95% confidence interval [CI], 39.5 to 51.9). The effectiveness of vaccination with two doses of BNT162b2 and no previous infection was negligible (-1.1%; 95% CI, -7.1 to 4.6), but nearly all persons had received their second dose more than 6 months earlier. The effectiveness of three doses of BNT162b2 and no previous infection was 52.2% (95% CI, 48.1 to 55.9). The effectiveness of previous infection and two doses of BNT162b2 was 55.1% (95% CI, 50.9 to 58.9), and the effectiveness of previous infection and three doses of BNT162b2 was 77.3% (95% CI, 72.4 to 81.4). Previous infection alone, BNT162b2 vaccination alone, and hybrid immunity all showed strong effectiveness (>70%) against severe, critical, or fatal Covid-19 due to BA.2 infection. Similar results were observed in analyses of effectiveness against BA.1 infection and of vaccination with mRNA-1273. CONCLUSIONS: No discernable differences in protection against symptomatic BA.1 and BA.2 infection were seen with previous infection, vaccination, and hybrid immunity. Vaccination enhanced protection among persons who had had a previous infection. Hybrid immunity resulting from previous infection and recent booster vaccination conferred the strongest protection. (Funded by Weill Cornell Medicine-Qatar and others.).

Covid-19 Vaccine Protection among Children and Adolescents in Qatar.

BACKGROUND: The BNT162b2 vaccine against coronavirus disease 2019 (Covid-19) has been authorized for use in children 5 to 11 years of age and adolescents 12 to 17 years of age but in different antigen doses. METHODS: We assessed the real-world effectiveness of the BNT162b2 vaccine against infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among children and adolescents in Qatar. To compare the incidence of SARS-CoV-2 infection in the national cohort of vaccinated participants with the incidence in the national cohort of unvaccinated participants, we conducted three matched, retrospective, target-trial, cohort studies - one assessing data obtained from children 5 to 11 years of age after the B.1.1.529 (omicron) variant became prevalent and two assessing data from adolescents 12 to 17 years of age before the emergence of the omicron variant (pre-omicron study) and after the omicron variant became prevalent. Associations were estimated with the use of Cox proportional-hazards regression models. RESULTS: Among children, the overall effectiveness of the 10-µg primary vaccine series against infection with the omicron variant was 25.7% (95% confidence interval [CI], 10.0 to 38.6). Effectiveness was highest (49.6%; 95% CI, 28.5 to 64.5) right after receipt of the second dose but waned rapidly thereafter and was negligible after 3 months. Effectiveness was 46.3% (95% CI, 21.5 to 63.3) among children 5 to 7 years of age and 16.6% (95% CI, -4.2 to 33.2) among those 8 to 11 years of age. Among adolescents, the overall effectiveness of the 30-µg primary vaccine series against infection with the omicron variant was 30.6% (95% CI, 26.9 to 34.1), but many adolescents had been vaccinated months earlier. Effectiveness waned over time since receipt of the second dose. Effectiveness was 35.6% (95% CI, 31.2 to 39.6) among adolescents 12 to 14 years of age and 20.9% (95% CI, 13.8 to 27.4) among those 15 to 17 years of age. In the pre-omicron study, the overall effectiveness of the 30-µg primary vaccine series against SARS-CoV-2 infection among adolescents was 87.6% (95% CI, 84.0 to 90.4) and waned relatively slowly after receipt of the second dose. CONCLUSIONS: Vaccination in children was associated with modest, rapidly waning protection against omicron infection. Vaccination in adolescents was associated with stronger, more durable protection, perhaps because of the larger antigen dose. (Funded by Weill Cornell Medicine-Qatar and others.).

Waning of BNT162b2 Vaccine Protection against SARS-CoV-2 Infection in Qatar.

BACKGROUND: Waning of vaccine protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or coronavirus disease 2019 (Covid-19) is a concern. The persistence of BNT162b2 (Pfizer-BioNTech) vaccine effectiveness against infection and disease in Qatar, where the B.1.351 (or beta) and B.1.617.2 (or delta) variants have dominated incidence and polymerase-chain-reaction testing is done on a mass scale, is unclear. METHODS: We used a matched test-negative, case-control study design to estimate vaccine effectiveness against any SARS-CoV-2 infection and against any severe, critical, or fatal case of Covid-19, from January 1 to September 5, 2021. RESULTS: Estimated BNT162b2 effectiveness against any SARS-CoV-2 infection was negligible in the first 2 weeks after the first dose. It increased to 36.8% (95% confidence interval [CI], 33.2 to 40.2) in the third week after the first dose and reached its peak at 77.5% (95% CI, 76.4 to 78.6) in the first month after the second dose. Effectiveness declined gradually thereafter, with the decline accelerating after the fourth month to reach approximately 20% in months 5 through 7 after the second dose. Effectiveness against symptomatic infection was higher than effectiveness against asymptomatic infection but waned similarly. Variant-specific effectiveness waned in the same pattern. Effectiveness against any severe, critical, or fatal case of Covid-19 increased rapidly to 66.1% (95% CI, 56.8 to 73.5) by the third week after the first dose and reached 96% or higher in the first 2 months after the second dose; effectiveness persisted at approximately this level for 6 months. CONCLUSIONS: BNT162b2-induced protection against SARS-CoV-2 infection appeared to wane rapidly following its peak after the second dose, but protection against hospitalization and death persisted at a robust level for 6 months after the second dose. (Funded by Weill Cornell Medicine-Qatar and others.).

Estimating protection afforded by prior infection in preventing reinfection: Applying the test-negative study design.

The COVID-19 pandemic has highlighted the need to use infection testing databases to rapidly estimate effectiveness of prior infection in preventing reinfection ($P{E}_S$) by novel SARS-CoV-2 variants. Mathematical modeling was used to demonstrate a theoretical foundation for applicability of the test-negative, case-control study design to derive $P{E}_S$. Apart from the very early phase of an epidemic, the difference between the test-negative estimate for $P{E}_S$ and true value of $P{E}_S$ was minimal and became negligible as the epidemic progressed. The test-negative design provided robust estimation of $P{E}_S$ and its waning. Assuming that only 25% of prior infections are documented, misclassification of prior infection status underestimated $P{E}_S$, but the underestimate was considerable only when >50% of the population was ever infected. Misclassification of latent infection, misclassification of current active infection, and scale-up of vaccination all resulted in negligible bias in estimated $P{E}_S$. The test-negative design was applied to national-level testing data in Qatar to estimate $P{E}_S$ for SARS-CoV-2. $P{E}_S$ against SARS-CoV-2 Alpha and Beta variants was estimated at 97.0% (95% CI: 93.6-98.6) and 85.5% (95% CI: 82.4-88.1), respectively. These estimates were validated using a cohort study design. The test-negative design offers a feasible, robust method to estimate protection from prior infection in preventing reinfection.

Seroprevalence of herpes simplex virus type 1 and type 2 among the migrant workers in Qatar.

BACKGROUND: Limited data exists on herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections in migrant populations. This study investigated HSV-1 and HSV-2 seroprevalences and associations among craft and manual workers (CMWs) in Qatar who constitute 60% of Qatar's population. METHODS: A national population-based cross-sectional seroprevalence survey was conducted on the CMW population, all men, between July 26 and September 9, 2020. 2,612 sera were tested for anti-HSV-1 IgG antibodies using HerpeSelect 1 ELISA IgG kits and for anti-HSV-2 IgG antibodies using HerpeSelect 2 ELISA IgG kits (Focus Diagnostics, USA). Univariable and multivariable logistic regression analyses were conducted to identify associations with HSV-1 and HSV-2 infections. RESULTS: Serological testing identified 2,171 sera as positive, 403 as negative, and 38 as equivocal for HSV-1 antibodies, and 300 sera as positive, 2,250 as negative, and 62 as equivocal for HSV-2 antibodies. HSV-1 and HSV-2 seroprevalences among CMWs were estimated at 84.2% (95% CI 82.8-85.6%) and 11.4% (95% CI 10.1-12.6%), respectively. HSV-1 infection was associated with nationality, educational attainment, and occupation. HSV-2 infection was associated with age, nationality, and educational attainment. CONCLUSIONS: Over 80% of CMWs are infected with HSV-1 and over 10% are infected with HSV-2. The findings highlight the need for sexual health programs to tackle sexually transmitted infections among the CMW population.

Severity, Criticality, and Fatality of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Beta Variant.

Beta (B.1.351)-variant coronavirus disease 2019 (COVID-19) disease was investigated in Qatar. Compared with the Alpha (B.1.1.7) variant, odds (95% confidence interval) of progressing to severe disease, critical disease, and COVID-19-related death were 1.24-fold (1.11-1.39), 1.49-fold (1.13-1.97), and 1.57-fold (1.03-2.43) higher, respectively, for the Beta variant.

Assessment of the Risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Reinfection in an Intense Reexposure Setting.

BACKGROUND: Risk of reinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. We assessed the risk and incidence rate of documented SARS-CoV-2 reinfection in a cohort of laboratory-confirmed cases in Qatar. METHODS: All SARS-CoV-2 laboratory-confirmed cases with at least 1 polymerase chain reaction-positive swab that was ≥45 days after a first positive swab were individually investigated for evidence of reinfection. Viral genome sequencing of the paired first positive and reinfection viral specimens was conducted to confirm reinfection. RESULTS: Out of 133 266 laboratory-confirmed SARS-CoV-2 cases, 243 persons (0.18%) had at least 1 subsequent positive swab ≥45 days after the first positive swab. Of these, 54 cases (22.2%) had strong or good evidence for reinfection. Median time between the first swab and reinfection swab was 64.5 days (range, 45-129). Twenty-three of the 54 cases (42.6%) were diagnosed at a health facility, suggesting presence of symptoms, while 31 (57.4%) were identified incidentally through random testing campaigns/surveys or contact tracing. Only 1 person was hospitalized at the time of reinfection but was discharged the next day. No deaths were recorded. Viral genome sequencing confirmed 4 reinfections of 12 cases with available genetic evidence. Reinfection risk was estimated at 0.02% (95% confidence interval [CI], .01%-.02%), and reinfection incidence rate was 0.36 (95% CI, .28-.47) per 10 000 person-weeks. CONCLUSIONS: SARS-CoV-2 reinfection can occur but is a rare phenomenon suggestive of protective immunity against reinfection that lasts for at least a few months post primary infection.

Introduction and expansion of the SARS-CoV-2 B.1.1.7 variant and reinfections in Qatar: A nationally representative cohort study.

BACKGROUND: The epidemiology of the SARS-CoV-2 B.1.1.7 (or Alpha) variant is insufficiently understood. This study's objective was to describe the introduction and expansion of this variant in Qatar and to estimate the efficacy of natural infection against reinfection with this variant. METHODS AND FINDINGS: Reinfections with the B.1.1.7 variant and variants of unknown status were investigated in a national cohort of 158,608 individuals with prior PCR-confirmed infections and a national cohort of 42,848 antibody-positive individuals. Infections with B.1.1.7 and variants of unknown status were also investigated in a national comparator cohort of 132,701 antibody-negative individuals. B.1.1.7 was first identified in Qatar on 25 December 2020. Sudden, large B.1.1.7 epidemic expansion was observed starting on 18 January 2021, triggering the onset of epidemic's second wave, 7 months after the first wave. B.1.1.7 was about 60% more infectious than the original (wild-type) circulating variants. Among persons with a prior PCR-confirmed infection, the efficacy of natural infection against reinfection was estimated to be 97.5% (95% CI: 95.7% to 98.6%) for B.1.1.7 and 92.2% (95% CI: 90.6% to 93.5%) for variants of unknown status. Among antibody-positive persons, the efficacy of natural infection against reinfection was estimated to be 97.0% (95% CI: 92.5% to 98.7%) for B.1.1.7 and 94.2% (95% CI: 91.8% to 96.0%) for variants of unknown status. A main limitation of this study is assessment of reinfections based on documented PCR-confirmed reinfections, but other reinfections could have occurred and gone undocumented. CONCLUSIONS: In this study, we observed that introduction of B.1.1.7 into a naïve population can create a major epidemic wave, but natural immunity in those previously infected was strongly associated with limited incidence of reinfection by B.1.1.7 or other variants.

Association of Prior SARS-CoV-2 Infection With Risk of Breakthrough Infection Following mRNA Vaccination in Qatar.

Importance: The effect of prior SARS-CoV-2 infection on vaccine protection remains poorly understood. Objective: To assess protection from SARS-CoV-2 breakthrough infection after mRNA vaccination among persons with vs without prior SARS-CoV-2 infection. Design, Setting, and Participants: Matched-cohort studies in Qatar for the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) vaccines. A total of 1 531 736 individuals vaccinated with either vaccine between December 21, 2020, and September 19, 2021, were followed up beginning 14 days after receiving the second dose until September 19, 2021. Exposures: Prior SARS-CoV-2 infection and COVID-19 vaccination. Main Outcomes and Measures: Incident SARS-CoV-2 infection, defined as a polymerase chain reaction (PCR)-positive nasopharyngeal swab regardless of reason for PCR testing or presence of symptoms. Cumulative incidence was calculated using the Kaplan-Meier estimator method. Results: The BNT162b2-vaccinated cohort comprised 99 226 individuals with and 290 432 matched individuals without prior PCR-confirmed infection (median age, 37 years; 68% male). The mRNA-1273-vaccinated cohort comprised 58 096 individuals with and 169 514 matched individuals without prior PCR-confirmed infection (median age, 36 years; 73% male). Among BNT162b2-vaccinated persons, 159 reinfections occurred in those with and 2509 in those without prior infection 14 days or more after dose 2. Among mRNA-1273-vaccinated persons, 43 reinfections occurred in those with and 368 infections in those without prior infection. Cumulative infection incidence among BNT162b2-vaccinated individuals was an estimated 0.15% (95% CI, 0.12%-0.18%) in those with and 0.83% (95% CI, 0.79%-0.87%) in those without prior infection at 120 days of follow-up (adjusted hazard ratio for breakthrough infection with prior infection, 0.18 [95% CI, 0.15-0.21]; P < .001). Cumulative infection incidence among mRNA-1273-vaccinated individuals was an estimated 0.11% (95% CI, 0.08%-0.15%) in those with and 0.35% (95% CI, 0.32%-0.40%) in those without prior infection at 120 days of follow-up (adjusted hazard ratio, 0.35 [95% CI, 0.25-0.48]; P < .001). Vaccinated individuals with prior infection 6 months or more before dose 1 had statistically significantly lower risk for breakthrough infection than those vaccinated less than 6 months before dose 1 (adjusted hazard ratio, 0.62 [95% CI, 0.42-0.92]; P = .02 for BNT162b2 and 0.40 [95% CI, 0.18-0.91]; P = .03 for mRNA-1273 vaccination). Conclusions and Relevance: Prior SARS-CoV-2 infection was associated with a statistically significantly lower risk for breakthrough infection among individuals receiving the BNT162b2 or mRNA-1273 vaccines in Qatar between December 21, 2020, and September 19, 2021. The observational study design precludes direct comparisons of infection risk between the 2 vaccines.

Willingness to participate in genome testing: a survey of public attitudes from Qatar.

Genomics has the potential to revolutionize medical approaches to disease prevention, diagnosis, and treatment, but it does not come without challenges. The success of a national population-based genome program, like the Qatar Genome Program (QGP), depends on the willingness of citizens to donate samples and take up genomic testing services. This study explores public attitudes of the Qatari population toward genetic testing and toward participating in the QGP. A representative sample of 837 adult Qataris was surveyed in May 2016. Approximately 71% of respondents surveyed reported that they were willing to participate in the activities of the QGP. Willingness to participate was significantly associated with basic literacy in genetics, a family history of genetic diseases, and previous experience with genetic testing through premarital screening. Respondents cited the desire to know more about their health status as the principle motivation for participating, while lack of time and information were reported as the most important barriers. With QGP plans to ramp up the scale of its national operation toward more integration into clinical care settings, it is critical to understand public attitudes and their determinants. The results demonstrate public support but also identify the need for more education and individual counseling that not only provide information on the process, challenges, and benefits of genomic testing, but that also address concerns about information security.

The Reproductive Agency Scale (RAS-17): development and validation in a cross-sectional study of pregnant Qatari and non-Qatari Arab Women.

BACKGROUND: Sustainable Development Goal (SDG) 5 prioritizes women's empowerment and gender equality, alone and as drivers of other SDGs. Efforts to validate universal measures of women's empowerment have eclipsed efforts to develop refined measures in local contexts and lifecycle stages. Measures of women's empowerment across the reproductive lifecycle remain limited, including in the Arab Middle East. METHODS: In this sequential, mixed-methods study, we developed and validated the Reproductive Agency Scale 17 (RAS-17) in 684 women having a normal pregnancy and receiving prenatal care at Hamad Medical Corporation in Doha, Qatar. Participants varied in age (19-46 years), trimester, gravidity (M3.3[SD2.1], range 1-14), and parity (M2.1[SD1.5], range 0-7). Using qualitative research and questionnaire reviews, we developed 44 pregnancy-specific and non-pregnancy-specific agency items. We performed exploratory then confirmatory factor analyses (EFA/CFA) in random split-half samples and multiple-group CFA to assess measurement invariance of the scale across Qatari (n = 260) and non-Qatari Arab (n = 342) women. RESULTS: Non-Qatari women agreed more strongly than Qatari women that every woman should have university education, and working outside home benefitted women. Qatari women agreed more strongly than non-Qatari women that a woman should be free to sell her property. Qatari women reported more influence than non-Qatari women in decisions about spending their money (M4.6 versus M4.4), food they can eat (M4.4 versus M4.2), and rest during pregnancy (M4.5 versus M4.2). Qatari and non-Qatari women typically reported going most places with permission if accompanied. A 17-item, three-factor model measuring women's intrinsic agency or awareness of economic rights (5 items) and instrumental agency in decision-making (5 items) and freedom of movement (7 items) had good fit and was partially invariant across groups. CONCLUSIONS: The RAS-17 is a contextual, multidimensional measure of women's reproductive agency validated in pregnant Qatari and non-Qatari Arab women. This scale integrates pregnancy-specific and non-pregnancy-specific items in dimensions of intrinsic agency and instrumental agency relevant to Arab women of reproductive age. The RAS-17 may be useful to screen for low reproductive agency as a predictor of maternal and perinatal outcomes. The RAS-17 should be validated in other samples to assess its full applicability across the reproductive life cycle.

Human and economic resources for empowerment and pregnancy-related mental health in the Arab Middle East: a systematic review.

This systematic review synthesizes research on the influence of human and economic resources for women's empowerment on their pre- and postnatal mental health, understudied in the Arab world. We include articles using quantitative methods from PubMed and Web of Science. Two researchers reviewed databases and selected articles, double reviewing 5% of articles designated for inclusion. Twenty-four articles met inclusion criteria. All 24 articles measured depression as an outcome, and three included additional mental health outcomes. Nine of 17 studies found an inverse association between education and depression; two of 12 studies found contradictory associations between employment and depression, and four of six studies found a positive association between financial stress and depression. These results suggest that there is a negative association between education and depression and a positive association between financial stress and depression among women in the Arab world. Firm conclusions warrant caution due to limited studies meeting inclusion criteria and large heterogeneity in mental health scales used, assessment measures, and definitions of human and economic resources for women's empowerment. It is likely that education reduces depression among postpartum women and that financial stress increases their depression. These findings can be used to aid in the design of interventions to improve mother and child outcomes. However, more research in the Arab world is needed on the relationship between human and economic resources for women's empowerment and perinatal mental health, and more consistency is needed in how resources and mental health are measured.

Validation of three mental health scales among pregnant women in Qatar.

OBJECTIVES: The objective of this study is to validate three mental health scales in a targeted sample of pregnant Arab women living in Qatar: the Kuwait University Anxiety Scale, the Perceived Stress Scale, and the Edinburgh Postnatal Depression Scale. METHODS: Random split-half exploratory factor analysis and confirmatory factor analyses (n = 336; n = 331), conducted separately, were used to evaluate scale dimensionality, factor loadings, and factor structure of the KUAS, the PSS, and the EPDS. RESULTS: Fit statistics for the three scales suggested adequate fit to the data and estimated factor loadings were positive, similar in magnitude, and were significant. The final CFA model for the KUAS supported a 19-item, two factor structure. CFA models also confirmed 8- and 10-item, single-factor structures for the PSS and EPDS, respectively. CONCLUSIONS: The validation of scales for these aspects of mental health in Arab pregnant women is critical to ensure appropriate screening, identification, and treatment to reduce the risk of sequelae in women and their children. Findings offer a useful comparison to mental-health scale validations in other Arab contexts.

The effects of citizenship status on service utilization and general satisfaction with healthcare: a cross-cultural study.

OBJECTIVE: To explore the role of citizenship status as a predictor of general satisfaction with healthcare services in Qatar, including potential interaction with utilization and health insurance coverage type. DESIGN: A cross-sectional survey conducted in 2012. SETTING: A household survey in the State of Qatar in the Arab Gulf. PARTICIPANTS: A nationally representative sample of 2750 citizens and noncitizens aged 18 years and older. MAIN OUTCOME: General satisfaction status with Qatar's healthcare system. MEASURES: Citizenship status, healthcare utilization, health insurance type. RESULTS: Citizens were significantly less likely to be satisfied with Qatar's healthcare system than noncitizens (odds ratio (OR) = 0.30, P < 0.001). The association between private health insurance and overall satisfaction was not significantly different between citizens and noncitizens (P = 0.19). However, the association between utilization of healthcare services and overall satisfaction was moderated by citizenship (P < 0.001). Among citizens, non-users were less likely to be satisfied than recent users (OR = 1.88, P < 0.05), while the opposite pattern was observed among noncitizens (OR = 0.51, P < 0.05). These patterns persisted even after controlling for potential confounders. CONCLUSIONS: The study revealed significant population differences in satisfaction between recent users and non-users within citizenship groups. These differences may stem from different expectations with respect to healthcare services. Understanding these expectations may have important policy implications for cross-cultural contexts.

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

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, 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. Methods: A 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. Results: The 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. Discussion: A 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.