Antibody Response to SARS-CoV-2: A Cohort Study in Qatar's Primary Care Settings.

BACKGROUND: Globally, countries are rolling out Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) quarantine policies and vaccination programs. Research studies are needed in helping understand the likelihood of acquired immunity to reinfection and identify priority groups for vaccination to inform them. This study aimed to assess period prevalence and longitudinal changes in antibody levels after SARS-CoV-2 infection in Qatari primary care settings. METHODS: A cohort study design with 2 data collection phases was undertaken-Phase 1 (conducted in July 2020) and Phase 2 (conducted in October 2020). A stratified random sampling technique by age, gender and nationality was utilized to identify the study sample. The total sample size required for the study was estimated to be 2102. Participants were invited to an appointment where they were administered a questionnaire and provided samples for polymerase chain reaction and Immunoglobulin G immunoassay tests. RESULTS: A total of 943 individuals participated in both Phase 1 and Phase 2. In this cohort, seroprevalence of SARS-CoV-2 was found to be 12% (N = 113) in Phase 1 and 17.2% (N = 162) in Phase 2. Of the 113 participants who were seropositive in Phase 1, 38.1% (CI 29.5-47.2%, N = 43) had a reduction, 54.9% (CI 45.7-63.8%, N = 62) had no change, and 7.1% (CI 3.4-12.9%, N = 8) had an increase in IgG titer in Phase 2. All (N = 18) participants aged 10 to 17 years retained their antibodies. The proportion of men who retained their antibodies was slightly higher compared to women-92.5% (N = 74) and 87.9% (N = 29) respectively. Similarly, symptomatic individuals (97.8%; N = 45) had a higher antibody retention compared with asymptomatic individuals (86.4%; N = 57). CONCLUSIONS: This study provides preliminary information on the longitudinal changes in antibody levels after SARS-CoV-2 infection. These findings will help inform quarantine policies and vaccination programs.

Epidemiology of SARS-CoV2 in Qatar's primary care population aged 10 years and above.

BACKGROUND: There is an urgent need to elucidate the epidemiology of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) and characterize its potential impact. Investing in characterising the SARS-CoV2 will help plan and improve the response to the pandemic. Furthermore, it will help identify the most efficient ways of managing the pandemic, avoiding public health policies and interventions that may be unduly restrictive of normal activity or unnecessarily costly. This paper describes the design and reports findings of a population based epidemiological study undertaken to characterise SARS-CoV2 in Qatar using limited resources in a timely manner. METHODS: Asymptomatic individuals ≥10 years registered with Qatar's publicly funded primary health provider were eligible. A stratified random sampling technique was utilized to identify the study sample. Participants were invited to an appointment where they completed a questionnaire and provided samples for polymerase chain reaction and Immunoglobulin M and G immunoassay tests. Data collected were analyzed to calculate point and period prevalence by sociodemographic, lifestyle and clinical characteristics. RESULTS: Of 18,918 individuals invited for the study, 2084 participated (response rate 10.8%). The overall point prevalence and period prevalence were estimated to be 1.6% (95% CI 1.1-2.2) and 14.6% (95% CI 13.1-16.2) respectively. Period prevalence of SARS-CoV2 infection was not considerably different across age groups (9.7-19.8%). It was higher in males compared to females (16.2 and 12.7% respectively). A significant variation was observed by nationality (7.1 to 22.2%) and municipalities (6.9-35.3%). CONCLUSIONS: The study provides an example of a methodologically robust approach that can be undertaken in a timely manner with limited resources. It reports much-needed epidemiological data about the spread of SARS-CoV2. Given the low prevalence rates, majority of the population in Qatar remains susceptible. Enhanced surveillance must continue to be in place, particularly due to the large number of asymptomatic cases observed. Robust contact tracing and social distancing measures are key to prevent future outbreaks.

COVID-19 Surveillance in the Primary Health Care Population of Qatar: Experience of Prioritizing Timeliness Over Representativeness When Sampling the Population.

SARS-CoV2 a new emerging Corona Virus Disease in humans, which called for containment measures by many countries. The current paper aims to discuss the impact of two different sampling methodologies when executing a drive through COVID-19 survey on the quality of estimated disease burden measures. Secondary data analysis of a pilot cross-sectional survey targeting Qatar's primary health care registered population was done. Two groups with different sampling methods were compared for estimating COVID-19 point prevalence using molecular testing for nasopharyngeal swabs. The first group is a stratified random sample non-proportional to size (N = 260). A total of 16 population strata based on age group, gender, and nationality were sampled. The second group is the Open invitation group (N = 841). The results showed that the two groups were obviously and significantly different in age and nationality. Besides, reporting of COVID-19 symptoms was more frequent in the open invitation group (28.2%) than the random sample (16.2%). The open invitation group overestimated the symptomatic COVID-19 prevalence rate by more than four times, while it overestimated the asymptomatic COVID-19 cases by a small margin. The overall prevalence rate of active COVID-19 cases in the open invitation sample (13.3%) was almost double that of the random sample (6.9%). Furthermore, using population sampling weights reduced the prevalence rate to 0.8%. The lesson learned here is that it is wise to consider the magnitude of bias introduced in a surveillance system when relying on convenient sampling approaches in response to time constraints.

The prevalence of COVID 19 among PHCC workers and its relation to place of works and medical comorbidities

Background: COVID 19 disease has a wide spectrum of severity. This has made the study of the risk factors affecting the severity, open for research, beginning from blood grouping to obesity and other comorbidities. The infectious nature of the disease made it important to take very strict measures in infection control through all the medical facilities. Maintaining the wellbeing of health care workers is a priority during this pandemic Aim: This study aims to find out the prevalence of COVID - 19 among PHCC staff during the period of March to end of September 2020 and to correlate between the place of work and position of the staff and to determine the risk factors associated with COVID-19 infection (age, gender, pre- existing Comorbidities, and workplace). Methods: A cross-sectional descriptive study design without any staff identifiers, data for all PHCC staff attending primary health care and their characteristics: Sociodemographic data: Age, Gender, Nationality, Weight, Height, BMI, Job title, PCR test results, Medical history, Place of Work (health care center), blood group captured through medical electronic system (CERNER). Results: A total 5,062 staff were included, 1,541 (30.4 %) were males, 3,521 (69.6%) were females. Overall positive COVID19 cases were 489 representing 9.7% of the sample and the total negative cases were 4,573 representing 90.3% of the sample. 348 (71.2%) positive cases were females and 141 (28.8%) positive cases were males. Of the total sample, medical staff were 4,061 and the non-medical sample were 1,001. Among medical staff the positive cases were 349 (8.6%) and 140 positive cases were non-medical staff, 14 % of 1001 total cases. Conclusion: Although PHCC also adopted a staff protection policy which included the waiver of attendance registration, the use of (masks, gloves, PPE), hand hygiene, isolation rooms for swabbing and the proper management of medical waste that resulted from dealing with COVID -19 patients, the prevalence of Covid 19 infection among PHCC staff during the period from march first till 30 September found to be 9.7 %, but neither the position at work or comorbidities were found to be statistically significant with COVID 19 infection. Pharmacists were the most exposed medical staff category to COVID19 infection due to direct contact with all patients visiting PHCC, while dentists were second because they dealt with open mouth patients. Of non-medical staff, cashiers and billing staff were the highest category because the deal with all visitors and are exposed to probably infected material ( redit cards, currency) in addition to lack of awareness and training. No statistical significant results were found among comorbidities cases, reflecting the fact that their exposure is not affected by exposure at work rather than their community exposure. [ABSTRACT FROM AUTHOR] Copyright of Middle East Journal of Family Medicine is the property of Medi+WORLD International Pty. Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)