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1.
Clin Infect Dis ; 2022 Aug 30.
Article in English | MEDLINE | ID: mdl-36041003
3.
Nat Commun ; 13(1): 4675, 2022 08 09.
Article in English | MEDLINE | ID: mdl-35945213

ABSTRACT

There is significant genetic distance between SARS-CoV-2 Omicron (B.1.1.529) variant BA.1 and BA.2 sub-lineages. This study investigates immune protection of infection with one sub-lineage against reinfection with the other sub-lineage in Qatar during a large BA.1 and BA.2 Omicron wave, from December 19, 2021 to March 21, 2022. Two national matched, retrospective cohort studies are conducted to estimate effectiveness of BA.1 infection against reinfection with BA.2 (N = 20,994; BA.1-against-BA.2 study), and effectiveness of BA.2 infection against reinfection with BA.1 (N = 110,315; BA.2-against-BA.1 study). Associations are estimated using Cox proportional-hazards regression models after multiple imputation to assign a sub-lineage status for cases with no sub-lineage status (using probabilities based on the test date). Effectiveness of BA.1 infection against reinfection with BA.2 is estimated at 94.2% (95% CI: 89.2-96.9%). Effectiveness of BA.2 infection against reinfection with BA.1 is estimated at 80.9% (95% CI: 73.1-86.4%). Infection with the BA.1 sub-lineage appears to induce strong, but not full immune protection against reinfection with the BA.2 sub-lineage, and vice versa, for at least several weeks after the initial infection.


Subject(s)
COVID-19 , Reinfection , Humans , Proportional Hazards Models , Retrospective Studies , SARS-CoV-2
4.
Infect Drug Resist ; 15: 3871-3879, 2022.
Article in English | MEDLINE | ID: mdl-35903580

ABSTRACT

Objective: To determine the prevalence of SARS-CoV-2 virus infection among female workers who were restricted to working from home compared with those who continued to attend in-person work. Methods: As part of national surveillance program, serum samples for SARS-CoV-2 antibody testing and nasopharyngeal swabs for SARS-CoV-2 PCR were obtained on 1636 female school staff and salon/spa workers who were restricted to work remotely (restricted group) and 1190 female health-care workers who continued in-person work (unrestricted group). Results: Seropositivity rate was 5.1% among the restricted and 22.7% among the unrestricted group (P < 0.0001). Presence of symptoms at baseline (adjusted odds ratio [aOR], 2.88; 95% CI 2.09-3.97), contact with a confirmed case (aOR 2.34; 95% CI 1.37-3.98), and unrestricted work type (aOR 4.71; 95% CI 3.24-6.86) were associated with a higher risk of infection, while increasing age was associated with a lower risk of infection. Conclusion: Prevalence of SARS-CoV-2 infection as determined by seropositivity was higher among women who were not subject to workplace restrictions.

5.
Open Forum Infect Dis ; 9(7): ofac311, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35880233

ABSTRACT

Background: Comparative effectiveness of coronavirus disease 2019 (COVID-19) vaccines across patient subgroups is poorly understood and essential to precisely targeting vaccination strategies. Methods: We used the US Department of Veterans Affairs COVID-19 Shared Data Resource to identify veterans who utilize VA health care and had no documented severe acute respiratory syndrome coronavirus 2 infection before December 11, 2020. Using a test-negative case-control design (TND), we used conditional logistic regression with adjustment for covariates to estimate vaccine effectiveness (VE) over time for veterans who received 2 doses of mRNA vaccines or 1 dose of Ad26.Cov2.S. Results: We identified 4.8 million veterans with a mean age of 64 years, of whom 58% had ≥1 chronic disease. Vaccine effectiveness for symptomatic infections, hospitalizations, and ICU admission or death declined over time and varied by the type of vaccine (P < 0.01). VE estimates against symptomatic infection during months 1 and 7 for mRNA-1273 compared with BNT162b2 were 89.7% (95% CI, 84.4%-93.0%) and 57.3% (95% CI, 48.4%-64.7%) vs 81.6% (95% CI, 75.9%-85.9%) and 22.5% (95% CI, 7.2%-35.2%) for individuals age <65 years and 78.4% (95% CI, 71.1%-83.9%) and 36.2% (95% CI, 27.7%-43.6%) vs 66.3% (95% CI, 55.7%-74.4%) and -23.3% (95% CI, -40.5% to -8.2%) in subjects age ≥65 years; against hospitalization 92.0% (95% CI, 76.1%-97.3%) and 83.1% (95% CI, 66.8%-91.4%) vs 85.6% (95% CI, 72.6%-92.4%) and 57.0% (95% CI, 31.2%-73.2%) in subjects age <65 years and 66.1% (95% CI, 45.3%-79.0%) and 64.7% (95% CI, 55.2%-72.3%) vs 61.0% (95% CI, 41.3%-74.2%) and 1.7% (95% CI, -22.0% to 20.8%) in those age ≥65 years; against ICU admission or death 89.2% (95% CI, 49.5%-97.7%) and 84.4% (95% CI, 59.0%-94.1%) vs 87.6% (95% CI, 61.0%-96.1%) and 66.4% (95% CI, 7.7%-87.8%) in subjects age <65 years and 75.4% (95% CI, 51.7%-87.5%) and 73.8 (95% CI, 62.9%-81.5%) vs 67.4% (95% CI, 32.6%-84.3%) and 29.3% (95% CI, 2.3%-48.9%) in subjects age ≥65 years, respectively (P interaction < .01 for all comparisons). Similarly, mRNA-1273 was more effective than BNT162b2 in veterans with >1 chronic disease. Conclusions: mRNA-1273 was more effective than BNT162b2 in older veterans and those with chronic diseases.

6.
PLoS One ; 17(7): e0271324, 2022.
Article in English | MEDLINE | ID: mdl-35853026

ABSTRACT

We developed a Coronavirus Disease 2019 (COVID-19) risk score to guide targeted RT-PCR testing in Qatar. The Qatar national COVID-19 testing database, encompassing a total of 2,688,232 RT-PCR tests conducted between February 5, 2020-January 27, 2021, was analyzed. Logistic regression analyses were implemented to derive the COVID-19 risk score, as a tool to identify those at highest risk of having the infection. Score cut-off was determined using the ROC curve based on maximum sum of sensitivity and specificity. The score's performance diagnostics were assessed. Logistic regression analysis identified age, sex, and nationality as significant predictors of infection and were included in the risk score. The ROC curve was generated and the area under the curve was estimated at 0.63 (95% CI: 0.63-0.63). The score had a sensitivity of 59.4% (95% CI: 59.1%-59.7%), specificity of 61.1% (95% CI: 61.1%-61.2%), a positive predictive value of 10.9% (95% CI: 10.8%-10.9%), and a negative predictive value of 94.9% (94.9%-95.0%). The concept and utility of a COVID-19 risk score were demonstrated in Qatar. Such a public health tool can have considerable utility in optimizing testing and suppressing infection transmission, while maximizing efficiency and use of available resources.


Subject(s)
COVID-19 , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19 Testing , Humans , Public Health , Qatar/epidemiology , ROC Curve , Retrospective Studies , Risk Factors , SARS-CoV-2/genetics , Sensitivity and Specificity
7.
J Glob Health ; 12: 05032, 2022 Jul 06.
Article in English | MEDLINE | ID: mdl-35788085

ABSTRACT

Background: Understanding the disease severity associated with the Omicron variant of the SARS-CoV-2 virus is important in determining appropriate management strategies at the individual and population levels. We determined the severity of SARS-CoV-2 infection in persons infected with the Omicron vs the Delta variant. Methods: We identified individuals with SARS-CoV-2 infection with Delta and propensity-score matched controls with Omicron variant infection from the National COVID-19 Database in Qatar. We excluded temporary visitors to Qatar, those with a prior documented infection, those ≤18 years old, and those with <14 days of follow up after the index test positive date. We determined the rates of admission to the hospital, admission to intensive care unit, mechanical ventilation, or death among those infected with the Delta or Omicron variants. Results: Among 9763 cases infected with the Delta variant and 11 310 cases infected with the Omicron variant, we identified 3926 propensity-score matched pairs. Among 3926 Delta infected, 3259 (83.0%) had mild, 633 (16.1%) had moderate and 34 (0.9%) had severe/critical disease. Among 3926 Omicron infected, 3866 (98.5%) had mild, 59 (1.5%) had moderate, and only 1 had severe/critical disease (overall P < 0.001). Factors associated with less moderate or severe/critical disease included infection with Omicron variant (aOR = 0.06; confidence interval (CI) = 0.05-0.09) and vaccination including a booster (aOR = 0.30; 95% CI = 0.09-0.99). Conclusions: Omicron variant infection is associated with significantly lower severity of disease compared with the Delta variant. Vaccination continues to offer strong protection against severe/critical disease.


Subject(s)
COVID-19 , Adolescent , Humans , Qatar/epidemiology , SARS-CoV-2/genetics , Severity of Illness Index
8.
Nat Commun ; 13(1): 3647, 2022 06 25.
Article in English | MEDLINE | ID: mdl-35752687

ABSTRACT

The SARS-CoV-2 Omicron variant is thought to cause less severe disease among the general population, but disease severity among at-risk populations is unknown. We performed a retrospective analysis using a matched cohort of United States veterans to compare the disease severity of subjects infected during Omicron and Delta predominant periods within 14 days of initial diagnosis. We identified 22,841 matched pairs for both periods. During the Omicron period, 20,681 (90.5%) veterans had mild, 1308 (5.7%) moderate, and 852 (3.7%) severe disease. During the Delta predominant period, 19,356 (84.7%) had mild, 1467 (6.4%) moderate, and 2018 (8.8%) severe disease. Moderate or severe disease was less likely during the Omicron period and more common among older subjects and those with more comorbidities. Here we show that infection with the Omicron variant is associated with less severe disease than the Delta variant in a high-risk older veteran population, and vaccinations provide protection against severe or critical disease.


Subject(s)
COVID-19 , Veterans , COVID-19/epidemiology , Cohort Studies , Humans , Retrospective Studies , SARS-CoV-2/genetics , Severity of Illness Index , United States/epidemiology
9.
N Engl J Med ; 387(1): 21-34, 2022 07 07.
Article in English | MEDLINE | ID: mdl-35704396

ABSTRACT

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.).


Subject(s)
2019-nCoV Vaccine mRNA-1273 , BNT162 Vaccine , COVID-19 , Immunity, Innate , Immunization , SARS-CoV-2 , 2019-nCoV Vaccine mRNA-1273/immunology , 2019-nCoV Vaccine mRNA-1273/therapeutic use , BNT162 Vaccine/immunology , BNT162 Vaccine/therapeutic use , COVID-19/immunology , COVID-19/prevention & control , COVID-19/virology , Case-Control Studies , Humans , Immunity, Innate/immunology , Immunization, Secondary , Recurrence , SARS-CoV-2/immunology , Vaccination
10.
Nat Commun ; 13(1): 3082, 2022 06 02.
Article in English | MEDLINE | ID: mdl-35654888

ABSTRACT

SARS-CoV-2 Omicron BA.1 and BA.2 subvariants are genetically divergent. We conducted a matched, test-negative, case-control study to estimate duration of protection of the second and third/booster doses of mRNA COVID-19 vaccines against BA.1 and BA.2 infections in Qatar. BNT162b2 effectiveness was highest at 46.6% (95% CI: 33.4-57.2%) against symptomatic BA.1 and at 51.7% (95% CI: 43.2-58.9%) against symptomatic BA.2 infections in the first three months after the second dose, but declined to ~10% or below thereafter. Effectiveness rebounded to 59.9% (95% CI: 51.2-67.0%) and 43.7% (95% CI: 36.5-50.0%), respectively, in the first month after the booster dose, before declining again. Effectiveness against COVID-19 hospitalization and death was 70-80% after the second dose and >90% after the booster dose. mRNA-1273 vaccine protection showed similar patterns. mRNA vaccines provide comparable, moderate, and short-lived protection against symptomatic BA.1 and BA.2 Omicron infections, but strong and durable protection against COVID-19 hospitalization and death.


Subject(s)
COVID-19 , SARS-CoV-2 , 2019-nCoV Vaccine mRNA-1273 , BNT162 Vaccine , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines , Case-Control Studies , Humans , Qatar/epidemiology , SARS-CoV-2/genetics , Vaccines, Synthetic , mRNA Vaccines
12.
Health Sci Rep ; 5(3): e542, 2022 May.
Article in English | MEDLINE | ID: mdl-35601034

ABSTRACT

Background and Aims: Clinical characteristics and factors associated with mortality in patients admitted to the intensive care unit (ICU) in countries with low case fatality rates (CFR) are unknown. We sought to determine these in a large cohort of critically ill COVID-19 patients in Qatar and explore the early mortality predictors. Methods: We retrospectively studied the clinical characteristics and outcomes in patients admitted to the ICU at the national referral hospital for COVID-19 patients in Qatar. Logistic regression analysis was used to determine factors associated with mortality. Results: Between March 7 and July 16, 2020, a total of 1079 patients with COVID-19 were admitted to the ICU. The median (IQR) age of patients was 50 (41-59) years. Diabetes (47.3%) and hypertension (42.6%) were the most common comorbidities. In-hospital mortality was 12.6% overall and 25.9% among those requiring mechanical ventilation. Factors independently associated with mortality included older age ([OR]; 2.3 [95% CI; 1.92-2.75] for each 10-year increase in age, p < 0.001), chronic kidney disease (OR; 1.9 [95% CI; 1.02-3.54], p = 0.04), active malignancy (OR; 6.15 [95% CI; 1.79-21.12], p = 0.004), lower platelet count at ICU admission (OR; 1.41 [95% CI; 1.13-1.75] for each 100 × 103/µl decrease, p = 0.002), higher neutrophil-to-lymphocyte ratio at admission (OR; 1.01 [95% CI; 1-1.02] for each 1- point increase, p = 0.016), higher serum ferritin level at admission (OR; 1.05 [(95% CI; 1.02-1.08] for each 500 µg/L increase, p = 0.002), and higher serum bilirubin level at admission (OR; 1.19 [95% CI; 1.04-1.36] for each 10 µmol/L increase, p = 0.01). Conclusions: The mortality rate among critically ill COVID-19 patients is low in Qatar compared to other countries. Older age, chronic kidney disease, active malignancy, higher neutrophil-to-lymphocyte ratios, lower platelet counts, higher serum ferritin levels, and higher serum bilirubin levels are independent predictors of in-hospital mortality.

14.
Clin Infect Dis ; 2022 May 03.
Article in English | MEDLINE | ID: mdl-35511586

ABSTRACT

BACKGROUND: The current SARS-CoV-2 vaccines may be less effective against the Omicron variant. With recent resurgence of SARS-CoV-2 cases, the role of booster doses of the vaccine needs to be highlighted. METHODS: Using a retrospective cohort study design emulating a target trial, we determined the relative effectiveness of a homologous booster dose of a SARS-CoV-2 mRNA vaccine compared with primary series alone in preventing infection, hospitalization, and intensive care unit (ICU) admission, and death in the Department of Veterans Affairs healthcare system in the US. Among infection-free survivors who received two doses of an mRNA vaccine prior to April 30, 2021, we identified those who received a booster between September 22 and December 25, 2021 and 1:1 matched individuals who did not receive a booster. RESULTS: Among 2,384,272 previously uninfected persons with two doses of an mRNA vaccine by April 30, 2021, we identified 462,950 booster recipients between September 22 and December 25, 2021 who were matched 1:1 with non-booster recipients. RVE (95% CI) was 19% (17-22%) for confirmed infection, 52% (46-57%) for hospitalization, and 83% (65-92%) for ICU admission or death. Recipients of the mRNA-1273 vaccine had a lower cumulative incidence of infections and hospitalizations compared with BNT-162b2 vaccine (log-rank p-value <0.001 for both comparisons). CONCLUSION: While the RVE of SARS-CoV-2 mRNA booster vaccine dose in preventing infection against the Omicron variant is low, the RVE is substantial in preventing hospitalization and high in preventing the most severe/critical disease.

15.
Clin Infect Dis ; 75(1): e361-e367, 2022 Aug 24.
Article in English | MEDLINE | ID: mdl-35404391

ABSTRACT

SHORT SUMMARY: Severe acute respiratory syndrome coronavirus 2 infection from the Omicron variant in children/adolescents is less severe than infection from the Delta variant. Those 6 to <18 years also have less severe disease than those <6 years old. BACKGROUND: There are limited data assessing coronavirus 2019 (COVID-19) disease severity in children/adolescents infected with the Omicron variant. METHODS: We identified children and adolescents <18 years of age with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with Delta and propensity score-matched controls with Omicron variant infection from the National COVID-19 Database in Qatar. Primary outcome was disease severity, determined by hospital admission, admission to the intensive care unit (ICU), or mechanical ventilation within 14 days of diagnosis, or death within 28 days. RESULTS: Among 1735 cases with Delta variant infection between 1 June and 6 November 2021, and 32 635 cases with Omicron variant infection between 1 January and 15 January 2022, who did not have prior infection and were not vaccinated, we identified 985 propensity score-matched pairs. Among those who were Delta infected, 84.2% had mild, 15.7% had moderate, and 0.1% had severe/critical disease. Among those who were Omicron infected, 97.8% had mild, 2.2% had moderate, and none had severe/critical disease (P < .001). Omicron variant infection (vs Delta) was associated with significantly lower odds of moderate or severe/critical disease (adjusted odds ratio [AOR], 0.12; 95% confidence interval [CI], .07-.18). Those aged 6-11 and 12 to <18 years had lower odds of developing moderate or severe/critical disease compared with those younger than age 6 years (aOR, 0.47; 95% CI, .33-.66 for 6-11 year olds; aOR, 0.45; 95% CI, .21-.94 for 12 to <18 year olds). CONCLUSIONS: Omicron variant infection in children/adolescents is associated with less severe disease than Delta variant infection as measured by hospitalization rates and need for ICU care or mechanical ventilation. Those 6 to <18 years of age also have less severe disease than those <6 years old.


Subject(s)
COVID-19 , Adolescent , Child , Humans , Respiration, Artificial , SARS-CoV-2 , Severity of Illness Index
16.
N Engl J Med ; 386(19): 1804-1816, 2022 05 12.
Article in English | MEDLINE | ID: mdl-35263534

ABSTRACT

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.).


Subject(s)
/immunology , COVID-19 , COVID-19/epidemiology , COVID-19/immunology , COVID-19/prevention & control , COVID-19 Vaccines , Cohort Studies , Humans , Immunization, Secondary , Immunogenicity, Vaccine , Qatar/epidemiology , RNA, Messenger , Retrospective Studies , SARS-CoV-2 , Vaccines, Synthetic
17.
Clin Infect Dis ; 75(1): e579-e584, 2022 Aug 24.
Article in English | MEDLINE | ID: mdl-35245940

ABSTRACT

BACKGROUND: Knowledge of the vaccine effectiveness (VE) of a third or booster vaccine dose in preventing SARS-CoV-2 infection or its consequences is critical in developing recommendations for their use. We determined relative VE of 3 vs 2 doses of an mRNA vaccine in preventing symptomatic SARS-CoV-2 infection, hospitalization, and severe/critical disease. METHODS: Among veterans who had received 2 doses of an mRNA vaccine by 30 April 2021, we identified those who received a third dose of the same vaccine between 22 September and 24 November 2021 and 1:1 matched controls who had not received their third dose by then. Using Cox proportional hazards model, we calculated adjusted hazards ratios for symptomatic infection, hospitalization, and intensive care unit (ICU) admission or death after SARS-CoV-2-positive test. RESULTS: Among 2 321 366 veterans who received 2 doses of Pfizer BNT-162b2 or Moderna mRNA-1273 vaccine by 30 April 2021, we matched 395 686 persons who received a third dose of the same vaccine between 22 September and 24 November 2021 to controls who did not receive a third dose. Adjusted HRs (95% CI) were .15 (.11-.21) for symptomatic infection and .18 (.13-.26) for hospitalizations for 3 vs 2 doses, corresponding to relative VE of 85% and 82%. Five ICU admissions or deaths were observed (4 among recipients of 2 doses). There was no difference in VE between BNT162b2 versus mRNA-1273 recipients. CONCLUSIONS: A third dose of a SARS-CoV-2 mRNA vaccine is associated with high VE against symptomatic infection, hospitalization, and critical disease in the pre-Omicron era.


Subject(s)
COVID-19 , Viral Vaccines , 2019-nCoV Vaccine mRNA-1273 , BNT162 Vaccine , COVID-19/prevention & control , COVID-19 Vaccines , Humans , SARS-CoV-2 , Vaccine Efficacy , Vaccines, Synthetic , mRNA Vaccines
18.
Clin Infect Dis ; 75(1): e617-e622, 2022 Aug 24.
Article in English | MEDLINE | ID: mdl-35139175

ABSTRACT

BACKGROUND: Persons on chronic hemodialysis have a significantly diminished humoral immune response to SARS-CoV-2 vaccines. Whether this translates to reduced vaccine effectiveness (VE) is unknown. METHODS: We used the US Department of Veterans Affairs COVID-19 Shared Data Resource to identify all veterans who were tested for SARS-CoV-2 between 26 January and 31 August 2021. Using International Classification of Diseases, 10th edition, codes and attendance at a dialysis clinic/center, we identified those who were on chronic hemodialysis. We used a test-negative, case-control design using a doubly robust logistic regression model to determine the VE of the BNT-162b2 (Pfizer) or mRNA-1273 (Moderna) vaccines in preventing confirmed SARS-CoV-2 infection. RESULTS: Among 847 199 veterans tested for SARS-CoV-2 between 26 January and 31 August 2021, there were 6076 veterans on chronic hemodialysis. Among those, we identified 1270 cases (580 fully vaccinated) and 2959 controls (2120 fully vaccinated). The overall VE >14 days after the second dose in preventing documented infection was 68.2% (95% CI: 62.6-72.9%). VE was 68.9% (95% CI: 61.9-74.7%) for Pfizer BNT-162b2 and 66.7% (95% CI: 58.9-73.0%) for Moderna mRNA-1273 vaccine. There was no difference in VE by age (<70 vs >70 years), race, or sex. There were no events recorded in persons with a Charlson's comorbidity index score <2. CONCLUSIONS: VE of 2 doses of current mRNA vaccines in preventing SARS-CoV-2 infection in persons on chronic hemodialysis is lower than historic VE rates in the general population. Effects of additional doses in improving VE in this special population need further study.


Subject(s)
COVID-19 , Viral Vaccines , 2019-nCoV Vaccine mRNA-1273 , Aged , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Renal Dialysis , SARS-CoV-2 , Vaccines, Synthetic , mRNA Vaccines
19.
J Glob Health ; 12: 05004, 2022.
Article in English | MEDLINE | ID: mdl-35136602

ABSTRACT

BACKGROUND: The effective reproduction number, Rt , is a tool to track and understand pandemic dynamics. This investigation of Rt estimations was conducted to guide the national COVID-19 response in Qatar, from the onset of the pandemic until August 18, 2021. METHODS: Real-time "empirical" Rt Empirical was estimated using five methods, including the Robert Koch Institute, Cislaghi, Systrom-Bettencourt and Ribeiro, Wallinga and Teunis, and Cori et al. methods. Rt was also estimated using a transmission dynamics model (Rt Model-based ). Uncertainty and sensitivity analyses were conducted. Correlations between different Rt estimates were assessed by calculating correlation coefficients, and agreements between these estimates were assessed through Bland-Altman plots. RESULTS: Rt Empirical captured the evolution of the pandemic through three waves, public health response landmarks, effects of major social events, transient fluctuations coinciding with significant clusters of infection, and introduction and expansion of the Alpha (B.1.1.7) variant. The various estimation methods produced consistent and overall comparable Rt Empirical estimates with generally large correlation coefficients. The Wallinga and Teunis method was the fastest at detecting changes in pandemic dynamics. Rt Empirical estimates were consistent whether using time series of symptomatic PCR-confirmed cases, all PCR-confirmed cases, acute-care hospital admissions, or ICU-care hospital admissions, to proxy trends in true infection incidence. Rt Model-based correlated strongly with Rt Empirical and provided an average Rt Empirical . CONCLUSIONS: Rt estimations were robust and generated consistent results regardless of the data source or the method of estimation. Findings affirmed an influential role for Rt estimations in guiding national responses to the COVID-19 pandemic, even in resource-limited settings.


Subject(s)
COVID-19 , SARS-CoV-2 , Basic Reproduction Number , Humans , Pandemics , Qatar/epidemiology
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