Khaled Alabdulkareem

Background: Humoral immune responses to SARS-CoV-2 are well documented, yet the immunopathogenic mechanisms distinguishing severe from critical disease remain incompletely defined, particularly in Middle Eastern populations. We investigated antibody responses across levels of clinical severity in a Saudi Arabian cohort. Methods: In this multicentre study, we analysed 406 participants stratified into five clinical groups: controls, asymptomatic, mild, severe, and critically ill requiring intensive care unit (ICU) admission. SARS-CoV-2-specific IgG and IgM levels were quantified alongside surrogate ACE2-RBD neutralisation activity. Associations between humoral markers, demographic factors, comorbidities, and disease severity were assessed. Results: SARS-CoV-2-specific IgG and IgM levels differed significantly across disease severity groups (p < 0.001), with higher levels observed in groups with greater clinical severity. No significant difference in IgG or IgM levels was observed between the severe and ICU groups (IgG p = 0.384; IgM p = 0.768). While binding antibody levels were associated with severity, surrogate ACE2-RBD neutralising activity did not differ significantly across groups (p = 0.209). Increasing age (χ² = 44.5) and the presence of comorbidities (χ² = 31.9) were associated with more severe clinical categories, whereas sex was not. Conclusions: These findings suggest that antibody levels provide useful information about exposure and immune activation, but antibody quantity alone does not fully explain the transition from severe to critical disease. The results support interpreting serological measures alongside clinical factors such as age and chronic illness.

Background: In the Kingdom of Saudi Arabia, various COVID-19 vaccines were administered during the pandemic. However, region-specific real-word comparative data on their immunogenicity remain limited. This study aimed to assess the serological responses to Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), and AstraZeneca (ChAdOx1 nCoV-19) vaccines in a diverse population living in KSA. Methods: This observational study included 236 adults recruited from vaccination sites in Riyadh. Participants provided serum samples at predefined intervals: before the first dose, after the first dose, after the second dose, and post-vaccination infection (if applicable). IgG and neutralising antibodies were quantified using ELISA assays. Demographic and vaccination data, and their associations with antibody responses, were evaluated. Results: At baseline, 75.4% of participants were positive for SARS-CoV-2 IgG, suggesting high prior exposure. Marked incremental increases in IgG levels were observed after each vaccine dose. Both Moderna and Pfizer elicited stronger responses, with Pfizer inducing the strongest early response and Moderna achieving the highest overall titres. Among IgG-positive individuals, neutralising antibodies were detected in 98.1%. There were no statistically significant differences by age or gender, although males tended to show higher mean titres. Heterologous vaccine schedules induced comparable or enhanced immunogenicity relative to homologous schedules, supporting their use in flexible immunisation strategies. Conclusions: All COVID-19 vaccines administered in Saudi Arabia elicited robust antibody responses, particularly the mRNA-based vaccines. Our findings support their continued use and justify varied vaccination approaches, including mix-and-match booster strategies, to enhance community immunity.

The new coronavirus disease 2019 (COVID-19) is a major global concern. Due to the number of asymptomatic cases that go untested, the actual proportion of those who have been infected is likely to be higher than the reported prevalence. Thus, investigating the exact proportion of those who developed antibodies against the virus through serological surveys is crucial to identify the immune status of the population and direct public health decisions accordingly. The aim of this study is to estimate the seroprevalence of SARS-CoV-2 in the community and to describe the epidemiological characteristics of the discovered cases. Between July and October 2020, a cross-sectional sero-survey was conducted including a total of 15,873 serum samples collected from seven regions within the kingdom. Using a multistage convenient sampling, people were invited to participate in an interviewer-administrated questionnaire. Afterward, blood samples were collected and seroprevalence was determined using the SARS-CoV-2 virus IgG/IgM antibody detection kits (ELISA). A p-value of <0.05 and 95% CI were used to report the significance. The overall seroprevalence of SARS-CoV-2 in the sample was 17.0%, and Makkah region constituted the highest number of reactive cases (33.3%). There was a significant association between all comorbidities and having symptoms except for diabetes. In addition, age, education, nationality, and region were all significant predeterminants of sero-result. Also, contact with a confirmed or suspected case increased the risk of being seropositive by nearly 1.5 times. This study estimated the national seroprevalence of SARS-CoV-2 in Saudi Arabia to be 17%. At the time of this study, most of the population did not have the SARS-CoV-2 specific antibodies. This suggests that the population is still below the threshold of herd immunity and emphasizes the importance of mass vaccination programs and abiding by recommended prevention precautions.

Background: Saudi Arabia expedited the approval of some COVID-19 vaccines and launched mass vaccination campaigns. The aim of this study was to describe the demographics of vaccinated COVID-19 cases and compare the mortality rates of COVID-19 cases who were infected post-vaccination in Saudi Arabia. Methods: This was a retrospective cohort study. We retrieved data for COVID-19 cases who were infected pre- or post-vaccination and had received at least one injection of the Oxford–AstraZeneca or Pfizer–BioNTech vaccine from 4 December 2020 to 15 October 2021. Results: The number of patients who were infected and had received at least one dose of a COVID-19 vaccine was 281,744. Approximately 45% of subjects were infected post-vaccination, and 75% of subjects had received the Pfizer–BioNTech vaccine. Only 0.342% of the patients who were infected post-vaccination died, and 447 patients were admitted to ICUs. Most of the patients who were infected with COVID-19 post-vaccination and were admitted to ICUs (69.84%) had received only one dose of the vaccine (p < 0.0001). The mean time to infection for patients who had received one and two doses of the Oxford–AstraZeneca vaccine were 27 and 8 days longer than their counterparts who had received one and two doses of Pfizer–BioNTech vaccine, respectively. No difference in the odds of mortality between the Pfizer–BioNTech and Oxford–AstraZeneca vaccines was found (OR = 1.121, 95% CI = [0.907–1.386], p-value = 0.291). Patients who had received two doses of the vaccine had significantly lower odds of mortality compared to those who had received one dose (p < 0.0001). Conclusions: Vaccines are vital in combating the COVID-19 pandemic. The results of this study show no difference between the Pfizer–BioNTech and Oxford–AstraZeneca vaccines in the rate of mortality. However, the number of vaccine doses was significantly associated with a lower risk of mortality. Future studies should examine the effectiveness of different COVID-19 vaccines using real-world data and more robust designs.

The Saudi Ministry of Health (MOH) established a National School-Based Screening Program (NSBSP) for health screening of schoolchildren. Students from specific grades were systematically screened for several health problems, including obesity, visual and auditory problems, dental cavities, scoliosis, and attention-deficit/hyperactivity disorder (ADHD). This cross-sectional study aimed to determine the prevalence of these health problems among primary school students based on secondary data obtained from the NSBSP. We included 444,259 screened school children from the first and fourth grades of 50% of the selected schools (both private and public) across the Kingdom of Saudi Arabia (KSA) during the academic year 2018–2019. Among them, the most prevalent health problems identified were dental cavities (38.7%), eye refractory errors (10.9%), and overweight and obesity (10.5%); the less prevalent problems included ADHD (2.81%), auditory problems (0.6%), and scoliosis (0.48%). A greater prevalence of most health problems was observed in girls more than boys. The NSBSP successfully aided the detection of health conditions with high and low prevalence among primary school students in the KSA, and thus, the identification of health problems of specific concern. Implementation of effective school health services for the prevention, early detection, diagnosis, and treatment of these health problems are imperative.

Vaccine refusal or hesitancy is one of the significant issues that can have an adverse impact on people’s health and their countries’ economy. Additionally, vaccine acceptance or refusal could have a decisive role in controlling the COVID-19 pandemic. This study aims to investigate the factors affecting COVID-19 vaccine refusal and hesitancy among the general population in Saudi Arabia. The method is a cross-sectional survey using an online questionnaire, and data were collected from 1935 participants between 18 February 2021 and 1 April 2021. Out of 1935 participants aged ≥18 years and residing in Saudi Arabia, 46.9% reported their intention to receive the COVID-19 vaccine, 22.4% had received the vaccine, 9.5% did not intend to receive the vaccine, and 21.2% had not made their decision. In the multinomial logistic regression models, vaccine refusal was associated with age (OR: 0.961), nationality (OR: 0.182), monthly income of more than SAR 18,000 (OR: 2.325), chronic diseases (OR: 0.521), knowledge about the vaccine (OR: 0.937), and concerns about the vaccine (OR: 1.5). The hesitancy was associated with age (OR: 0.977), nationality (OR: 0.231), monthly income between SAR 6000 to 12,000 (OR: 0.607), chronic diseases (OR: 0.640), knowledge about the vaccine (OR: 0.907), and concerns about the vaccine (OR: 1.3). The main concerns about the vaccine were “COVID-19 vaccines are not tested enough on people”, “drug companies are interested in COVID-19 vaccine sales only”, and “COVID-19 vaccines have serious adverse effects”. Awareness programs and vaccination campaigns should consider people’s concerns and correct their misinformation.

The Ministry of Health (MOH) in the Kingdom of Saudi Arabia (KSA) established a National School-based Screening Program (NSBSP) for health screening of school-going children. Students from specific grades were systematically screened for several health problems including obesity, visual and auditory problems, dental cavities, scoliosis, and attention-deficit/hyperactivity disorder (ADHD). This cross-sectional study aimed to determine the prevalence of these health problems among primary school students based on secondary data obtained from the NSBSP. We included 444,259 screened school children from the 1st and 4th grades of 50% of the selected schools (both private and public) across the KSA during the academic year 2018-2019. Among them, the most prevalent health problems identified were dental cavities (38.7%), eye refractory errors (10.9%), and overweight and obesity (10.5%); the less prevalent problems included ADHD (2.81%), auditory problems (0.6%), and scoliosis (0.48%). A greater prevalence of most health problems was observed in girls than boys. The NSBSP successfully aided the detection of health conditions with high and low prevalence among primary school students in the KSA, and thus, identification of health problems of specific concern. Implementation of effective school health services for the prevention, early detection, diagnosis, and treatment of these health problems is imperative.

Background: Hajj is an annual religious ritual that takes place for a specific period in Makkah city. Every year, the Kingdom of Saudi Arabia hosts more than two million pilgrims from more than 160 countries around the world for Hajj. It is crucial to minimize illnesses among pilgrims. This study aimed to assess the impact of preventive measures on acute illnesses among pilgrims. Methods: A retrospective cross-sectional study was conducted during the Hajj season from August to September 2019. A random sample was extracted from electronic evaluation forms filled by professional health care workers at two airports in Saudi Arabia including pilgrims before their departure and after the end of hajj season. Results: The study included 2,479 pilgrims. The most frequently associated comorbidity was Diabetes Mellitus in 49.54%. Upper respiratory tract infection was found in 39.17% and was the most common illness reported. Comorbidities had a crude odds ratio (OR) of 2.67 with a p-value of 0.000 and an adjusted OR of 2.80 with p-value of 0.000. The pre-Hajj examination had an OR of 0.37 with a p-value 0.000 that remained significant even after adjusting age and gender. Hajj health education had a crude OR of 0.17 with a significant p-value of 0.000 and adjusted OR 0.39 with p-value 0.003. Conclusion: Based on the current observation, strict compliance with standard pre-Hajj clinical examination, health education, and the use of umbrella during Hajj seasons is recommended to reduce the impact of acute illness among pilgrims.

BACKGROUND: Currently, there is no proven effective therapy nor vaccine for the treatment of SARS-CoV-2. Evidence regarding the potential benefit of early administration of hydroxychloroquine (HCQ) therapy in symptomatic patients with Coronavirus Disease (COVID-19) is not clear. METHODS: This observational prospective cohort study took place in 238 ambulatory fever clinics in Saudi Arabia, which followed the Ministry of Health (MOH) COVID-19 treatment guideline. This guideline included multiple treatment options for COVID-19 based on the best available evidence at the time, among which was Hydroxychloroquine (HCQ). Patients with confirmed COVD-19 (by reverse transcriptase polymerase chain reaction (PCR) test) who presented to these clinics with mild to moderate symptoms during the period from 5-26 June 2020 were included in this study. Our study looked at those who received HCQ-based therapy along with supportive care (SC) and compared them to patients who received SC alone. The primary outcome was hospital admission within 28-days of presentation. The secondary outcome was a composite of intensive care admission (ICU) and/or mortality during the follow-up period. Outcome data were assessed through a follow-up telephonic questionnaire at day 28 and were further verified with national hospitalisation and mortality registries. Multiple logistic regression model was used to control for prespecified confounders. RESULTS: Of the 7,892 symptomatic PCR-confirmed COVID-19 patients who visited the ambulatory fever clinics during the study period, 5,541 had verified clinical outcomes at day 28 (1,817 patients in the HCQ group vs 3,724 in the SC group). At baseline, patients who received HCQ therapy were more likely to be males who did not have hypertension or chronic lung disease compared to the SC group. No major differences were noted regarding other comorbid conditions. All patients were presenting with active complaints; however, the HCQ groups had higher rates of symptoms compared to the SC group (fever: 84% vs 66.3, headache: 49.8 vs 37.4, cough: 44.5 vs 35.6, respectively). Early HCQ-based therapy was associated with a lower hospital admission within 28-days compared to SC alone (9.4% compared to 16.6%, RRR 43%, p-value p-value 0.001). Adjusting for age, gender, and major comorbid conditions, a multivariate logistic regression model showed a decrease in the odds of hospitalisation in patients who received HCQ compared to SC alone (adjusted OR 0.57 [95% CI 0.47-0.69], p-value ). The composite outcome of ICU admission and/or mortality was also lower for the HCQ group compared to the SC group controlling for potential confounders (adjusted OR 0.55 [95% CI 0.34-0.91], p-value 0.019). CONCLUSION: Early intervention with HCQ-based therapy in patients with mild to moderate symptoms at presentation is associated with lower adverse clinical outcomes among COVID-19 patients, including hospital admissions, ICU admission, and/or death.