The Hajj pilgrimage, held in the Kingdom of Saudi Arabia, is among the largest mass gatherings in the world. More than 2.5 million Muslim pilgrims assemble from over 180 countries worldwide to perform Hajj. The Saudi government recognized the potential risks associated with this event since the first novel coronavirus disease 2019 (COVID-19) case was detected in the country on March 2, 2020. The return of possibly infected pilgrims to their countries after this huge mass gathering event could have turned Hajj into a superspreading event during the global COVID-19 pandemic. A multidisciplinary Saudi team from governmental sectors, including the Global Center for Mass Gatherings Medicine, shared in the assessment, planning, execution, and success of this holy event to prevent the spread of disease. The World Health Organization welcomed the Saudi government's decision to protect the wellbeing and safety of pilgrims and strengthen regional and global health security. A total of 1,000 pilgrims from 160 different countries were randomly selected to perform the rituals. Of all the pilgrims, healthcare personnel, and nonmedical employees facilitating the rituals, no confirmed cases of COVID-19 were identified during or after Hajj. This article highlights the success of the risk mitigation plan in place during the Hajj pilgrimage in 2020 (1441 Hijri year) during the COVID-19 pandemic and the efforts of the Saudi government to prevent associated outbreaks.

Summary Sickle cell disease (SCD) in Saudi patients from the Eastern Province is associated with the Arab-Indian (AI) HBB (β-globin gene) haplotype. The phenotype of AI SCD in children was described as benign and was attributed to their high fetal haemoglobin (HbF). We conducted a hospital-based study to assess the pattern of SCD complications in adults. A total of 104 patients with average age of 27 years were enrolled. Ninety-six percent of these patients reported history of painful crisis; 47% had at least one episode of acute chest syndrome, however, only 15% had two or more episodes; symptomatic osteonecrosis was reported in 18%; priapism in 17%; overt stroke in 6%; none had leg ulcers. The majority of patients had persistent splenomegaly and 66% had gallstones. Half of the patients co-inherited α-thalassaemia and about one third had glucose-6-phosphate dehydrogenase deficiency. Higher HbF correlated with higher rate of splenic sequestration but not with other phenotypes. The phenotype of adult patients with AI SCD is not benign despite their relatively high HbF level. This is probably due to the continued decline in HbF level in adults and the heterocellular and variable distribution of HbF amongst F-cells.

Background and Aims:Blood donation from glucose-6-phosphate dehydrogenase (G6PD)-deficient and sickle cell trait (SCT) donors might alter the quality of the donated blood during processing, storage or in the recipient's circulatory system. The aim of this study was to determine the prevalence of G6PD deficiency and SCT among blood donors coming to King Khalid University Hospital (KKUH) in Riyadh. It was also reviewed the benefits and risks of transfusing blood from these blood donors.Materials and Methods:This cross-sectional study was conducted on 1150 blood samples obtained from blood donors that presented to KKUH blood bank during the period April 2006 to May 2006. All samples were tested for Hb-S by solubility test, alkaline gel electrophoresis; and for G6PD deficiency, by fluorescent spot test.Results:Out of the 1150 donors, 23 (2%) were diagnosed for SCT, 9 (0.78%) for G6PD deficiency and 4 (0.35%) for both conditions. Our prevalence of SCT and G6PD deficiency is higher than that of the general population of Riyadh.Conclusion:We recommend to screen all units for G6PD deficiency and sickle cell trait and to defer donations from donors with either of these conditions, unless if needed for special blood group compatibility, platelet apheresis or if these are likely to affect the blood bank inventory. If such blood is to be used, special precautions need to be undertaken to avoid complications in high-risk recipients.

BACKGROUND AND OBJECTIVES:Genetic studies suggest that the sickle cell mutation has arisen on at least four separate occasions in Africa and as a fifth independent mutation in the Eastern Province of Saudi Arabia or India. The pathophysiology of sickle cell disease (SCD) is essentially similar in these different areas although the frequency and severity of complications may vary between areas. The aim of this study was to evaluate the prevalence and outcome of acute chest syndrome (ACS) in SCD patients from Eastern province of Saudi Arabia in comparison with patients with African haplotypes.MATERIALS AND METHODS:This was a retrospective study involving 317 SCD patients who were two years or older, admitted to King Fahad Hospital Hofuf between January-May 2003 for different etiologies. Twenty six patients presented with different causes of ACS; 11 patients presented with different pathologies other than ACS, but had past history of ACS; 280 patients presented with different pathologies and never presented with ACS. Clinical features, CBC, Hb-electrophoresis, G6PD activity, cultures, chest X-ray, arterial oxygen saturation, blood transfusion rates and outcome were studied. Univariate and multiple regression analysis were carried out to evaluate influence on ACS. Comparison between SCD patients with ACS from this study and from Eastern province of Saudi Arabia to patients with African haplotypes were carried out, using data reported in the literature.RESULTS:During the period of this study, 37 patients with new or previous episodes of ACS were studied (accounting for 11.67% of admitted SCD patients). Most of the patients with ACS had only one episode, but five patients (13.51%) had had episodes or more. One patient died giving an in-hospital mortality rate of 1/26 (3.85%). Comparison of recurrence of ACS and mortality between SCD patients in Eastern province of Saudi Arabia to that of patients with African haplotype showed that recurrence is significantly lower (P<0.025) in patients from Eastern province compared to patients with African haplotype, mortality also is lower but not statistically significant.CONCLUSION:Acute chest syndrome in SCD patients in Eastern province of Saudi Arabia is relatively uncommon, but causes significant morbidity and mortality. Its prevalence and recurrence is low if compared to that of patients with African haplotypes.

Most sickle cell anemia (SCA) patients indigenous to the Eastern Province of Saudi Arabia have their HbS gene on the Arab-Indian (AI) HBB gene cluster haplotype. Their fetal hemoglobin (HbF) levels are near 20% and they have milder disease compared with SCA where the HbS gene is on African origin HBB haplotypes [1][2][3][4][5][6][7][8][9]. The AI haplotype is characterized by an Xmn1 restriction site at position 2158 5 0 to HBG2 (rs7482144), a Hinc2 site 5 0 to HBE (rs3834466) and other polymorphisms [10]. The causal elements that modify HbF might be in linkage disequilibrium with the b S globin gene in this Saudi population. We first performed homozygosity mapping using genome-wide single nucleotide polymorphisms (SNPs) in AI HbS homozygotes [11,12] and identified a single large autozygous region including the HBB cluster and surrounding genes. By next generation sequencing, we examined this region in these same individuals and identified several variants that included a SNP in the HBD promoter region at position 268 bp 5 0 to HBD (CCAAC > TCAAC). We found this SNP only when the HbS gene was on an AI haplotype and not in SCA with other haplotypes. This SNP was functional in reporter assays in K562 cells and is an AI haplotype-specific marker. Table I summarizes the patient characteristics. Using genome-wide SNP data from a limited number of cases, a region of autozygosity was found only in AI HbS homozygotes on chromosome 11 (coordinates 5,196,450-5,323,071). The region contains HBD, HBG1, HBG2, HBE1, and the Xmn1 5 0 HBG2 restriction site (rs7482144). By targeted deep sequencing of 400 kb of chromosome 11 (coordinates 5,143,424-5,543,424; average coverage 42x) in 4 AI patients 1,195 variants were found. A homozygous C-T variant 268 bp 5 0 HBD with high genotyping and mapping quality that was not in dbSNP build 135 or 1,000 Genomes, was present. Resequencing of 15.9 kb of chr11 (coordinates 5,253,531-5,269,435) by Sanger sequencing detected three new SNPs of which one was the 268 C > T SNP. We focused on this SNP because of its location within the Corfu deletion region and its location in the HBD promoter.The C > T SNP in the HBD promoter was found only in individuals with the AI haplotype. Saudi sickle cell trait carriers with the AI haplotype were heterozygous for this SNP; while siblings without HbS did not carry this mutation. Among 25 AI HbS-b 0 thalassemia patients, 16 were heterozygous at this site (C/T) and 9 were homozygous (T/T). All AI HbS-b 0 thalassemia patients who were homozygous T/T were also homozygous for the AI haplotype (Table I). Fifteen African American SCA patients with unusually high HbF, 54 Saudi SCA patients from the Southwestern Province (SW)-mainly Benin but including subjects with the Senegal haplotype-19 SW HbS-b 0 thalassemia patients, 16 SW sickle cell trait cases, and 25 normal Saudi controls did not carry the 268 HBD SNP. This SNP was not found in 1,094 individuals in 1,000 Genomes May 2011 release. It is important to note that hemoglobin electrophoresis results in Table I wer...

Allogeneic HSCT is the only curative treatment for SCD. In this study, we estimated the number of Saudi patients with SCD who are candidates for HSCT. We used the presence of overt stroke, recurrent ACS, and frequent severe pain crisis as indications for HSCT. We calculated the frequencies of these complications among a Saudi SCD cohort of 376 patients with SCD, 250 from SW and 126 from Eastern (E) provinces. We found that 59 (23.6%) of SW patients were transplant candidates compared to 22 (17.4%) from E province. It is estimated that about 61 000 patients with SCD live in Saudi Arabia. Thus, the projected number of Saudi patients with SCD who are candidates for HSCT is 10 536 patients. Of those, 2148 are children. The burden of SCD on HSCT centers in Saudi Arabia is substantial and is difficult currently to meet the demand. We recommend recruiting/training more transplant physicians and nurses, expand current capacity of centers if feasible, and open new transplant centers to make HSCT a practical therapeutic option for patients with severe SCD in Saudi Arabia.

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