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1.
J Travel Med ; 2022 Sep 30.
Article in English | MEDLINE | ID: covidwho-2051490

ABSTRACT

BACKGROUND: The future of the SARS-CoV-2 pandemic hinges on virus evolution and duration of immune protection of natural infection against reinfection. We investigated duration of protection afforded by natural infection, the effect of viral immune evasion on duration of protection, and protection against severe reinfection, in Qatar, between February 28, 2020 and June 5, 2022. METHODS: Three national, matched, retrospective cohort studies were conducted to compare incidence of SARS-CoV-2 infection and COVID-19 severity among unvaccinated persons with a documented SARS-CoV-2 primary infection, to incidence among those infection-naïve and unvaccinated. Associations were estimated using Cox proportional-hazard regression models. RESULTS: Effectiveness of pre-Omicron primary infection against pre-Omicron reinfection was 85.5% (95% CI: 84.8-86.2%). Effectiveness peaked at 90.5% (95% CI: 88.4-92.3%) in the 7th month after the primary infection, but waned to ~ 70% by the 16th month. Extrapolating this waning trend using a Gompertz curve suggested an effectiveness of 50% in the 22nd month and < 10% by the 32nd month. Effectiveness of pre-Omicron primary infection against Omicron reinfection was 38.1% (95% CI: 36.3-39.8%) and declined with time since primary infection. A Gompertz curve suggested an effectiveness of < 10% by the 15th month. Effectiveness of primary infection against severe, critical, or fatal COVID-19 reinfection was 97.3% (95% CI: 94.9-98.6%), irrespective of the variant of primary infection or reinfection, and with no evidence for waning. Similar results were found in sub-group analyses for those ≥50 years of age. CONCLUSIONS: Protection of natural infection against reinfection wanes and may diminish within a few years. Viral immune evasion accelerates this waning. Protection against severe reinfection remains very strong, with no evidence for waning, irrespective of variant, for over 14 months after primary infection.

2.
BMC Nephrol ; 23(1): 304, 2022 09 05.
Article in English | MEDLINE | ID: covidwho-2038672

ABSTRACT

BACKGROUND: There is a growing literature on guidelines regarding Ramadan fasting for chronic kidney disease (CKD) patients. However, most studies only consider the impact of fasting on renal function. This study additionally aims to assess factors influencing Ramadan fasting in patients with CKD. METHOD: This is a prospective before and after cohort study. CKD patients were counseled regarding fasting and followed-up post-Ramadan for renal function status, actual fasting behavior, and other relevant outcomes. RESULTS: Of the 360 patients who attended the pre-Ramadan consultation, 306 were reachable after Ramadan of whom 55.3% were female. Of these 306 67.1% reported that they had fasted, 4.9% had attempted to fast but stopped, and 28% did not fast at all. Of these 74 has a post-fasting kidney test. Of the patients, 68.1% had stage 3A CKD, 21.7% had stage 3B, 7.9% stage 4, and only 2% stage 5. Of those who fasted, 11.1% had a drop in Glomerular Filtration Rate (eGFR) of 20% or more. Those who did not fast (16.7%) presented a similar drop. Conversely, among the few who attempted to fast and had to stop, half showed a drop in eGFR of more than 20%. In linear regression, fasting was not associated with post-Ramadan eGFR, when controlling for age and baseline eGRF. There were 17 (5.6%) significant events, including one death. More significant events occurred among the group who fasted some of Ramadan days, 26.7% of the subjects experienced an adverse event-while 4.7% of the group who did not fast had a significant adverse event compared to 4.4% among those who fasted all Ramadan. CONCLUSION: Fasting was not a significant determining factor in renal function deterioration in the study's population, nor did it have any significant association with adverse events.


Subject(s)
Diabetes Mellitus, Type 2 , Renal Insufficiency, Chronic , Cohort Studies , Diabetes Mellitus, Type 2/complications , Female , Glomerular Filtration Rate , Humans , Islam , Male , Prospective Studies
3.
JAMA Netw Open ; 5(2): e2146798, 2022 02 01.
Article in English | MEDLINE | ID: covidwho-1694847

ABSTRACT

Importance: The incidence of infection during SARS-CoV-2 viral waves, the factors associated with infection, and the durability of antibody responses to infection among Canadian adults remain undocumented. Objective: To assess the cumulative incidence of SARS-CoV-2 infection during the first 2 viral waves in Canada by measuring seropositivity among adults. Design, Setting, and Participants: The Action to Beat Coronavirus study conducted 2 rounds of an online survey about COVID-19 experience and analyzed immunoglobulin G levels based on participant-collected dried blood spots (DBS) to assess the cumulative incidence of SARS-CoV-2 infection during the first and second viral waves in Canada. A sample of 19 994 Canadian adults (aged ≥18 years) was recruited from established members of the Angus Reid Forum, a public polling organization. The study comprised 2 phases (phase 1 from May 1 to September 30, 2020, and phase 2 from December 1, 2020, to March 31, 2021) that generally corresponded to the first (April 1 to July 31, 2020) and second (October 1, 2020, to March 1, 2021) viral waves. Main Outcomes and Measures: SARS-CoV-2 immunoglobulin G seropositivity (using a chemiluminescence assay) by major geographic and demographic variables and correlation with COVID-19 symptom reporting. Results: Among 19 994 adults who completed the online questionnaire in phase 1, the mean (SD) age was 50.9 (15.4) years, and 10 522 participants (51.9%) were female; 2948 participants (14.5%) had self-identified racial and ethnic minority group status, and 1578 participants (8.2%) were self-identified Indigenous Canadians. Among participants in phase 1, 8967 had DBS testing. In phase 2, 14 621 adults completed online questionnaires, and 7102 of those had DBS testing. Of 19 994 adults who completed the online survey in phase 1, fewer had an educational level of some college or less (4747 individuals [33.1%]) compared with the general population in Canada (45.0%). Survey respondents were otherwise representative of the general population, including in prevalence of known risk factors associated with SARS-CoV-2 infection. The cumulative incidence of SARS-CoV-2 infection among unvaccinated adults increased from 1.9% in phase 1 to 6.5% in phase 2. The seropositivity pattern was demographically and geographically heterogeneous during phase 1 but more homogeneous by phase 2 (with a cumulative incidence ranging from 6.4% to 7.0% in most regions). The exception was the Atlantic region, in which cumulative incidence reached only 3.3% (odds ratio [OR] vs Ontario, 0.46; 95% CI, 0.21-1.02). A total of 47 of 188 adults (25.3%) reporting COVID-19 symptoms during phase 2 were seropositive, and the OR of seropositivity for COVID-19 symptoms was 6.15 (95% CI, 2.02-18.69). In phase 2, 94 of 444 seropositive adults (22.2%) reported having no symptoms. Of 134 seropositive adults in phase 1 who were retested in phase 2, 111 individuals (81.8%) remained seropositive. Participants who had a history of diabetes (OR, 0.58; 95% CI, 0.38-0.90) had lower odds of having detectable antibodies in phase 2. Conclusions and Relevance: The Action to Beat Coronavirus study found that the incidence of SARS-CoV-2 infection in Canada was modest until March 2021, and this incidence was lower than the levels of population immunity required to substantially reduce transmission of the virus. Ongoing vaccination efforts remain central to reducing viral transmission and mortality. Assessment of future infection-induced and vaccine-induced immunity is practicable through the use of serial online surveys and participant-collected DBS.


Subject(s)
COVID-19 Serological Testing/statistics & numerical data , COVID-19/epidemiology , Immunoglobulin G/blood , Adolescent , Adult , Aged , COVID-19/immunology , Canada/epidemiology , Female , Humans , Incidence , Male , Middle Aged , Pandemics , SARS-CoV-2 , Surveys and Questionnaires
4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-322524

ABSTRACT

Background: The prevalence of infection in Canada’s COVID-19 viral waves, the predictors of infection, and the durability of antibody responses to infection remain undocumented.Methods: We organized serial online surveys of a representative group of Canadian adults about their COVID experience in the first (n=19 994;April-July 2020) and second viral wave (n=14 621;October 2020-March 2021). We paired these with IgG analysis of SARS-CoV-2 seroprevalence in self-collected dried blood spots after the first (n=8967) and second (n=7102) waves.Findings: Canada’s cumulative seroprevalence of SARS-CoV-2 among unvaccinated adults rose from ~2% after the first wave to 7% after the second. The seropositivity pattern was heterogeneous demographically and geographically during the first wave, but more homogeneous by the second (except in the four Atlantic Provinces, cumulative seroprevalence ~3%). Seroprevalence among visible minorities rose sharply from about 2% to >8% from the first to second wave. About a quarter of those reporting COVID symptoms during the second wave were seropositive, and in both waves the odds ratio (OR) of seropositivity for COVID symptoms exceeded six. About one-fifth of seropositives reported no symptoms. Of 134 seropositive adults in the first wave who were retested after the second, 83% (111) remained seropositive at least seven months later. Current smokers and people with a history of diabetes had lower ORs of infection. We calculated the absolute numbers of seropositive adults nationwide, which nearly quadrupled from 0.57 million to 1.90 million, with the largest increases among older adults. Infection fatality rates fell from 3.7 to 2.6/1000 infections, most notably at older ages.Interpretation: Canada’s COVID pandemic grew substantially between the first and second viral waves. Home-based DBS collection offers a practicable way to document evolving demographic and geographic patterns and to assess the levels and durability of population immunity, including from SARS-CoV-2 vaccination.Funding: Pfizer Global Medical, Unity Health Foundation, and the Canadian COVID-19 Immunity Task Force. Declaration of Interest: None to declare. Ethical Approval: The Ab-C study was approved by the Unity Health Toronto Ethics Review Board.

5.
J Epidemiol Glob Health ; 11(4): 344-353, 2021 12.
Article in English | MEDLINE | ID: covidwho-1446309

ABSTRACT

BACKGROUND: Prediction models are essential for informing screening, assessing prognosis, and examining options for treatment. This study aimed to assess the risk of SARS-CoV-2 infection severity in the Abu Dhabi population. METHODS: This is a mixed retrospective cohort study and case-control study to explore the associated factors of receiving treatment in the community, being hospitalized, or requiring complex hospital care among patients with a diagnosis of SARS-CoV-2. Of 641 patients included, 266 were hospitalized; 135 were hospitalized and either died or required complex care, i.e., required ICU admission, intubation, or oxygen and 131 did not develop severe disease requiring complex care. The third group ("controls") were 375 patients who were not hospitalized. Logistic regression analyses were used to study predictors of disease severity. RESULTS: Among hospitalized patients older age and low oxygen saturation at admission were the consistent and strongest predictors of an adverse outcome. Risk factors for the death in addition to age and low oxygen saturation were elevated white blood count and low reported physical activity. Chronic kidney disease and diabetes were also associated with more severe disease in logistic regression. The mortality rate among those with less than 30 min per week of physical activity was 4.9%, while the mortality rate was 0.35% for those with physical activity > 30 min at least once a week. The interval from the onset of symptoms to admission and mortality was found to have a significant inverse relationship, with worse survival for shorter intervals. CONCLUSION: Oxygen saturation is an important measure that should be introduced at screening sites and used in the risk assessment of patients with SARS-CoV-2. In addition, an older age was a consistent factor in all adverse outcomes, and other factors, such as low physical activity, elevated WBC, CKD, and DM, were also identified as risk factors.


Subject(s)
COVID-19 , Aged , Case-Control Studies , Hospitalization , Humans , Retrospective Studies , Risk Factors , SARS-CoV-2 , United Arab Emirates/epidemiology
6.
Lancet Reg Health Am ; 2: 100055, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1373179

ABSTRACT

BACKGROUND: Understanding vaccination intention during early vaccination rollout in Canada can help the government's efforts in vaccination education and outreach. METHOD: Panel members age 18 and over from the nationally representative Angus Reid Forum were invited to complete an online survey about their experience with COVID-19, including their intention to get vaccinated. Respondents were asked "When a vaccine against the coronavirus becomes available to you, will you get vaccinated or not?" Having no intention to vaccinate was defined as choosing "No - I will not get a coronavirus vaccination" as a response. Odds ratios and predicted probabilities are reported for no vaccine intentionality in demographic groups. FINDINGS: 14,621 panel members completed the survey. Having no intention to vaccinate against COVID-19 is relatively low overall (9%) with substantial variation among demographic groups. Being a resident of Alberta (predicted probability = 15%; OR 0.58 [95%CI 0.14-2.24]), aged 40-59 (predicted probability = 12%; OR 0.87 [0.78-0.97]), identifying as a visible minority (predicted probability = 15%; OR 0.56 [0.37-0.84]), having some college level education or lower (predicted probability = 14%) and living in households of at least five members (predicted probability = 13%; OR 0.82 [0.76-0.88]) are related to lower vaccination intention. INTERPRETATION: The study identifies population groups with greater and lesser intention to vaccinate in Canada. As the Canadian COVID-19 vaccination effort continues, policymakers may use this information to focus outreach, education, and other efforts on the latter groups, which also have had higher risks for contracting and dying from COVID-19. FUNDING: Pfizer Global Medical, Unity Health Foundation, Canadian COVID-19 Immunity Task Force.

7.
Biomed Res Int ; 2021: 6695707, 2021.
Article in English | MEDLINE | ID: covidwho-1133374

ABSTRACT

BACKGROUND: The UAE reported its first cluster of COVID 2019 in a group of returned travellers from Wuhan in January 2020. Various comorbidities are associated with worse disease prognosis. Understanding the impact of ethnicity on the disease outcome is an important public health issue but data from our region is lacking. AIM: We aim to identify comorbidities among patients hospitalized for COVID-19 that are associated with inhospital death. Also, to assess if ethnicity is correlated with increased risk of death. Patients and Method. The study is a single-centre, observational study in Shaikh Shakhbout Medical City, Abu Dhabi. Patients admitted with COVID-19, between 1st of March and the end of May, were enrolled. Records were studied for demography, comorbidity, and ethnicity. Ethnicity was divided into Arabs (Gulf, North Africa, and the Levant), South Asia (India, Pakistan, Bangladesh, Nepal, and Afghanistan), Africans, the Philippines, and others. The study was approved by the Department of Health of Abu Dhabi. RESULTS: 1075 patients (972 males) were enrolled. There were 24 nationalities under 5 ethnicity groups. Mean (average) age was 51 years (20-81). 101 (9.4%) died with deceased patients being significantly older. Death risk was not significantly influenced by sex. Duration of hospitalization among survivors was 6.2 days (0.2-40.4) with older patients and men staying longer (P < 0.01). Comorbidities of diabetes, hypertension, cardiovascular disease, chronic renal disease, liver disease, and malignancy were associated with higher risk of mortality univariate, but only liver disease reached statistical significance after adjustment for age. The highest percentage of death was seen in Arab Levant (21.2) followed by the Asian Afghan (18.8); however, differences among ethnicities did not reach statistical significance (P = 0.086). CONCLUSION: COVID-19 outcome was worse in older people and those with comorbidities. Men and older patients required longer hospitalization. Ethnicity is not seen to impact the risk of mortality.


Subject(s)
COVID-19/ethnology , COVID-19/mortality , Adult , Aged , Aged, 80 and over , Arabs/statistics & numerical data , Asia, Southeastern/ethnology , COVID-19/epidemiology , Cardiovascular Diseases/epidemiology , Comorbidity , Diabetes Mellitus/epidemiology , Female , Hospital Mortality , Humans , Length of Stay/statistics & numerical data , Male , Middle Aged , Obesity/epidemiology , Retrospective Studies , United Arab Emirates/epidemiology , Young Adult
9.
PLoS One ; 15(10): e0240778, 2020.
Article in English | MEDLINE | ID: covidwho-883686

ABSTRACT

Random population-based surveys to estimate prevalence of SARS-CoV2 infection causing coronavirus disease (COVID-19) are useful to understand distributions and predictors of the infection. In April 2020, the first-ever nationally representative survey in Canada polled 4,240 adults age 18 years and older about self-reported COVID experience in March, early in the epidemic. We examined the levels and predictors of COVID symptoms, defined as fever plus difficulty breathing/shortness of breath, dry cough so severe that it disrupts sleep, and/or loss of sense of smell; and testing for SARS-CoV-2 by respondents and/or household members. About 8% of Canadians reported that they and/or one or more household members experienced COVID symptoms. Symptoms were more common in younger than in older adults, and among visible minorities. Overall, only 3% of respondents and/or household members reported testing for SARS-CoV-2. Being tested was associated with having COVID symptoms, Indigenous identity, and living in Quebec. Periodic nationally representative surveys of symptoms, as well as SARS-CoV-2 antibodies, are required in many countries to understand the pandemic and prepare for the future.


Subject(s)
Betacoronavirus/genetics , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Coronavirus Infections/epidemiology , Health Surveys/methods , Pneumonia, Viral/diagnosis , Pneumonia, Viral/epidemiology , Self Report , Adolescent , Adult , Aged , COVID-19 , COVID-19 Testing , Coronavirus Infections/virology , Family Characteristics , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/virology , Polymerase Chain Reaction , Prevalence , Quebec/epidemiology , SARS-CoV-2 , Young Adult
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