Nationwide Seroprevalence of SARS-CoV-2 in Saudi Arabia (preprint)

Background: Estimated seroprevalence of Coronavirus Infectious Disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) is a critical evidence for a better evaluation of the virus spread and monitoring the progress of the COVID-19 pandemic in a population. In the Kingdom of Saudi Arabia (KSA), SARS-CoV-2 seroprevalence has been reported in specific regions, but an extensive nationwide study has not been reported. Here, we report a nationwide study to determine the prevalence of SARS-CoV-2 in the population of KSA during the pandemic, using serum samples from healthy blood donors, non-COVID patients and healthcare workers (HCWs) in six different regions of the kingdom, with addition samples from COVID-19 patients.Methods: A total of 11703 serum samples were collected from different regions of the KSA including; 5395 samples from residual healthy blood donors (D); 5877 samples from non-COVID patients collected through residual sera at clinical biochemistry labs from non-COVID patients (P); and 400 samples from consented HCWs. To determine the seroprevalence of SARS-CoV-2, all serum samples, in addition to positive control sera from RT-PCR confirmed COVID-19 patients, were subjected to in-house ELISA with a sample pooling strategy, which was further validated by testing individual samples that make up some of the pools, with a statistical estimation method to report seroprevalence estimates.Results: Overall (combining D and P groups) seroprevalence estimate was around 11% in Saudi Arabia; and was 5.1% (Riyadh), 1.5% (Jazan), 18.4% (Qassim), 20.8% (Hail), 14.7% (ER; Alahsa), and 18.8% in Makkah. Makkah samples were only D group and had a rate of 24.4% and 12.8% in the cities of Makkah and Jeddah, respectively. The seroprevalence in Saudi Arabia across the sampled areas would be 12 times the COVID-19 infection rate. Among HCWs, 7.5% (4.95-10.16 CI 95%) had reactive antibodies to SARS-CoV-2 without reporting any previously confirmed infection. This was higher in HCWs with hypertension. The study also presents the demographics and prevalence of co-morbidities in HCWs and subset of non-COVID-19 population.Conclusion: Our study estimates the overall national serological prevalence of COVID-19 in Saudi Arabia to be 11%, with an apparent disparity between regions.Funding Statement: This study was funded by KAIMRC, Grant: RC20/180; PI: Naif K. Alharbi.Declaration of Interests: The authors declare no conflict of interest.Ethics Approval Statement: The study was approved by the IRB in KAIMRC (Ministry of National Guard Health Affairs) for project number RC20-180. Residual samples from blood banks and clinical laboratories were obtained after an IRB approval. COVID-19 patients and HCWs signed informed consents to give blood samples.

Nationwide Seroprevalence of SARS-CoV-2 in Saudi Arabia (preprint)

Background: Estimated seroprevalence of Coronavirus Infectious Disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) is a critical evidence for a better evaluation of the virus spread and monitoring the progress of the COVID-19 pandemic in a population. In the Kingdom of Saudi Arabia (KSA), SARS-CoV-2 seroprevalence has been reported in specific regions, but an extensive nationwide study has not been reported. Here, we report a nationwide study to determine the prevalence of SARS-CoV-2 in the population of KSA during the pandemic, using serum samples from healthy blood donors, non-COVID patients and healthcare workers (HCWs) in six different regions of the kingdom, with addition samples from COVID-19 patients. Methods: A total of 11703 serum samples were collected from different regions of the KSA including; 5395 samples from residual healthy blood donors (D); 5877 samples from non-COVID patients collected through residual sera at clinical biochemistry labs from non-COVID patients (P); and 400 samples from consented HCWs. To determine the seroprevalence of SARS-CoV-2, all serum samples, in addition to positive control sera from RT-PCR confirmed COVID-19 patients, were subjected to in-house ELISA with a sample pooling strategy, which was further validated by testing individual samples that make up some of the pools, with a statistical estimation method to report seroprevalence estimates Results: Overall (combining D and P groups) seroprevalence estimate was around 11% in Saudi Arabia; and was 5.1% (Riyadh), 1.5% (Jazan), 18.4% (Qassim), 20.8% (Hail), 14.7% (ER; Alahsa), and 18.8% in Makkah. Makkah samples were only D group and had a rate of 24.4% and 12.8% in the cities of Makkah and Jeddah, respectively. The seroprevalence in Saudi Arabia across the sampled areas would be 12 times the COVID-19 infection rate. Among HCWs, 7.5% (4.95-10.16 CI 95%) had reactive antibodies to SARS-CoV-2 without reporting any previously confirmed infection. This was higher in HCWs with hypertension. The study also presents the demographics and prevalence of co-morbidities in HCWs and subset of non-COVID-19 population. Interpretation: Our study estimates the overall national serological prevalence of COVID-19 in Saudi Arabia to be 11%, with an apparent disparity between regions.

The Association of Country-Level Factors with Outcomes of COVID-19: Analysis of the pandemic after one million cases (preprint)

Background: Coronavirus infectious disease 2019 (COVID-19) is an ongoing global pandemic. Without a vaccine or an effective treatment in the near horizon, only public health measures have been effective in potentially reducing its impact. Due to the wide disparity in current response from individual countries, studying factors associated with public health measures may inform ongoing efforts. Therefore, this study aims to analyze the contributing factors across the globe with specific measures of the disease. Methods: This is a cross-sectional study that used publicly available data of COVID-19 cases as of April 6, 2020. We analyzed country public information on demographic and socioeconomic indicators published in different sources. The association between country-level variables and the incidence rate, the recovery rate, severity of the cases, and mortality rate were evaluated using regression techniques.  Results: Multiple factors were found to be significantly associated with COVID-19 outcomes. The number of tests per million, GDP per capita, a country population size of 2020, country median age, and life expectancy are associated with the incidence rate of COVID19. The yearly net change population, migrants, and tourism are associated with the recovery rate of COVID-19. The number of tests per million and male life expectancy are associated with the critical cases rate of COVID-19. Finally, the GDP per capita, land area (Km2), life expectancy, and tourism are associated with the mortality rate of COVID-19.  Conclusion: Overall, higher GDP per capita, median age, and a higher number of lab tests were found to be associated with more incidents of COVID-19 cases, which indicates a better and maintained system for detection, reporting, and management of the pandemic. This study suggests that investing in better screening and testing may reveal more cases that can be managed and controlled; while limiting travelers would further support the pandemic control.