Predicting immunogenicity of COVID-19 vaccines in hemodialysis patients with renal disease.

Individuals who are diagnosed with chronic kidney disease, particularly those receiving maintenance hemodialysis treatment, face a greater likelihood of suffering from severe symptoms and fatality due to COVID-19. This study aimed to explore the optimal vaccination approach for these individuals. The study used data analysis tasks such as data preprocessing, cleaning, and exploration, and machine learning models including linear regression, random forest, XGBoost, gradient boosting, AdaBoost, decision trees, Lasso, and ridge regression were used to construct the predictive model. The study found that the Lasso model performed the best overall in predicting anti-S IgG antibodies levels in response to COVID-19 vaccines for people with kidney failure with MAE of 8.81, RMSE of 19.59, and R2 value of 0.93. The adjusted R2 value for the Lasso model was also 0.93, indicating that the model's ability to explain the variance in the data was not affected by the number of predictors in the model. The Random Forest model best predicted the duration of immunogenicity, with R2 and adjusted R2 values of 0.71 and 0.69, respectively. The ensemble model that includes all eight models, i.e., Ridge, Lasso, Linear Regression, Random Forest, AdaBoost, Gradient Boosting, XGBoost, and Decision Tree, has the best performance with the lowest MAE, the lowest RMSE, the highest R2, and the highest adjusted R2 values of 3.91, 5.00, 0.73, and 0.72, respectively. However, further research is required to validate these models and extend their application to different populations and vaccine types, as well as considering other factors that may affect immune response to COVID-19 vaccines. These findings can be helpful in improving vaccination strategies and promoting public health.

Pandemic H1N1 influenza virus triggers a strong T helper cell response in human nasopharynx-associated lymphoid tissues.

The pH1N1 belongs to influenza A family that is sometimes transmitted to humans via contact with pigs. Human tonsillar immune cells are widely used as in vitro models to study responses to influenza viruses. In the current study, human memory (M) and naïve (N) T cells responses in mononuclear cells of tonsil (TMCs) and peripheral blood (PBMCs) were stimulated by pH1N1/sH1N1, and then stained for estimation of T cells proliferation index. Individuals with an anti-pH1N1 hemagglutination (HA) inhibition (HAI) titer of forty or greater exhibited stronger HA-specific M-CD4+ T cells responses to pH1N1 in TMCs/PBMCs than those with an HAI titer of less than forty (P < 0.01). In addition, a positive correlation was observed between proliferation indices of M-CD4+ T cells induced by exposure to sH1N1/pH1N1 (p < 0.01). Moreover, a strong correlation (p < 0.001) was detected between subjects' age and their HA-specific M-CD4+ T cells induced by pH1N1 exposure, indicating that this response was age-dependent. Finally, stimulation of TMCs with pH1N1-HA resulted in a significant M-CD8+ T cells response (p < 0.05). In conclusion, pH1N1 HA elicits a strong M-CD4+ T cells response in TMCs. Additionally, this response correlates with the response to sH1N1 suggesting cross-reactivity in T cells epitopes directed against HAs of both viral strains.

Robust memory humoral immune response to SARS-CoV-2 in the tonsils of adults and children.

Background: Adaptive humoral immunity against SARS-CoV-2 has mainly been evaluated in peripheral blood. Human secondary lymphoid tissues (such as tonsils) contain large numbers of plasma cells that secrete immunoglobulins at mucosal sites. Yet, the role of mucosal memory immunity induced by vaccines or natural infection against SARS-CoV-2 and its variants is not fully understood. Methods: Tonsillar mononuclear cells (TMNCs) from adults (n=10) and children (n=11) were isolated and stimulated using positive SARS-CoV-2 nasal swabs. We used endpoint enzyme-linked immunosorbent assays (ELISAs) for the measurement of anti-S1, -RBD, and -N IgG antibody levels and a pseudovirus microneutralization assay to assess neutralizing antibodies (nAbs) in paired serum and supernatants from stimulated TMNCs. Results: Strong systemic humoral response in previously SARS-CoV-2 infected and vaccinated adults and children was observed in accordance with the reported history of the participants. Interestingly, we found a significant increase in anti-RBD IgG (305 and 834 folds) and anti-S1 IgG (475 and 443 folds) in the stimulated TMNCs from adults and children, respectively, compared to unstimulated cells. Consistently, the stimulated TMNCs secreted higher levels of nAbs against the ancestral Wuhan strain and the Omicron BA.1 variant compared to unstimulated cells by several folds. This increase was seen in all participants including children with no known history of infection, suggesting that these participants might have been previously exposed to SARS-CoV-2 and that not all asymptomatic cases necessarily could be detected by serum antibodies. Furthermore, nAb levels against both strains were significantly correlated in adults (r=0.8788; p = 0.0008) and children (r = 0.7521; p = 0.0076), and they strongly correlated with S1 and RBD-specific IgG antibodies. Conclusion: Our results provide evidence for persistent mucosal humoral memory in tonsils from previously infected and/or vaccinated adults and children against recent and old variants upon re-exposure. They also highlight the importance of targeting mucosal sites with vaccines to help control infection at the primary sites and prevent potential breakthrough infections.

Attitude towards donation of the excised foreskin after circumcision surgery for research: A study from Madinah, Saudi Arabia.

Studies have shown the possibility of using the part of the foreskin removed after circumcision in the field of scientific and therapeutic research. Donations of tissues and organs are always associated with ethical challenges posed by bioethicists and societies to ensure the appropriate use of these tissues/organs. The purpose of this study was to understand the attitudes and awareness of parents/guardians regarding donation of excised foreskin to research and medical use. The study was based on a questionnaire and included 133 parents/guardians who visited Uhud Children's Hospital in Madinah, Saudi Arabia for newborn male circumcision. The results showed a high willingness (61.7%) to donate the extracted foreskin to research. The willingness to donate the extracted foreskin to research associated with undergraduate degree (P = 0.018), male sex (P = 0.011), high income (P = 0.029), and participation in previous research studies (P = 0.002). About 41.8% were convinced that written informed consent should be obtained before circumcision surgery, 38.1% (n = 51) were convinced that written informed consent should be taken after surgery, while the remaining 19.4% reported that the timing of written informed consent is unimportant. Finally, fear of excision of excess tissue (74.5%), lack of confidence in the research (68.6%), and potential for commercial use (64.7%) were the main barriers to unwillingness to donate the excised foreskin for research. In conclusion, a reasonable portion of Saudis agreed to donate their foreskin for research purposes. There is an urgent need to enhance awareness and attitudes towards tissue donation for research and therapeutic use.

Impaired humoral immune response to hepatitis B vaccine in patients on maintenance hemodialysis.

Hepatitis B virus (HBV) infection is a worldwide health problem. We aimed in this study to investigate the humoral immune response derived to HBV vaccine following completing the vaccine series in Madinah. Two hundred and two Saudi hemodialysis (HD) patients were included in this cross-sectional study. Mean concentration of Hepatitis B surface antibody (anti-HBs) was significantly higher among patients who received the vaccination twice compared to patients who received the vaccination only after starting hemodialysis (252 ± 489 mIU/mL vs. 144 ± 327 mIU/mL, respectively, p = 0.008). Almost half of the study sample were non-protected and showed anti-HBs concentration < 10 mlU/mL. In contrast, 20.3% (n = 41) were identified as poor responders (10-100 mlU/mL) and only 28.2% (n = 57) were identified as good responders (10-100 mlU/mL). However, the latter two groups were accounted as protected (48.5%, n = 98). Patients sex was associated with anti-HBs concentration (non-responders; poor responders; good responders), where significantly higher proportion of good responders were females compared to males (p = 0.007). In conclusion, HBV vaccine is efficient to elicit humoral immune response in hemodialysis patients.

COVID-19 vaccine in hemodialysis patients: Time for a boost.

OBJECTIVES: To evaluate anti-spike immunoglobulin G (IgG) antibody levels of hemodialysis patients and correlate them with the patients' demographic data and to evaluate these patients' need for a coronavirus disease-19 (COVID-19) vaccine booster. METHODS: A cross-sectional multi-center study carried out at King Abdulaziz Kidney Center, Hasan Tahir Hemodialysis Center, and Hayat Organization Hemodialysis Center in Al-Madinah Al-Munawarah, Saudi Arabia. Patients (n=167) who received a minimum single dose of COVID-19 vaccine were recruited. The samples were collected between March 2022 and January 2023. Anti-spike IgG antibody levels were measured using enzyme-linked immunosorbent assays. RESULTS: A significantly higher proportion of patients who received 3 doses of COVID-19 vaccine had positive serostatus compared with patients who received one or 2 doses (3 doses: 87.2%, one dose: 0.0%, 2 doses: 77.3%; p=0.000). Compared with patients who received one dose, significantly higher IgG antibody levels were detected in patients who received 2 (p=0.013) and 3 doses (p=0.025; n=35). In contrast, there was no significant difference in IgG antibody levels between patients who received 2 or 3 doses (p=0.45). Significant IgG antibody levels were detected in patients who received 2 and 3 doses (p=0.0125) compared with those received one vaccine dose (p=0.0004). Furthermore, patients who received 3 doses had significantly higher IgG antibody levels than patients who received 2 doses (p=0.000). CONCLUSION: The results show a dose-dependent association between IgG antibody levels and the number COVID-19 vaccines received. The study highlights the need for booster COVID-19 vaccination for patients on hemodialysis.

Live attenuated influenza vaccine induces broadly cross-reactive mucosal antibody responses to different influenza strains in tonsils.

Intranasal live attenuated influenza vaccine (LAIV) was used to stimulate tonsillar monocular cells (MNCs) following isolation. Haemagglutinin (HA) proteins of several influenza strains were used for the detection of HA-specific IgG, IgM and IgA antibodies using ELISA. Significant anti-sH1N1 HA IgG IgA and IgM antibody titres were detected in cell culture supernatants after stimulation (mean ± SE: 0.43 ± 0.09, mean ± SE: 0.23 ± 0.04 and mean ± SE: 0.47 ± 0.05 respectively, p < 0.01). LAIV stimulation of tonsillar MNCs induced significant IgG, IgA and IgM antibodies to the pH1N1 HA (mean ± SE:1.35 ± 0.12), (mean ± SE: 0.35 ± 0.06) and (mean ± SE: 0.58 ± 0.10) respectively, p < 0.01. Surprisingly, LAIV was shown to induce cross-reactive anti-aH5N1 HA antibodies (mean ± SE: 0.84 ± 0.20, p < 0.01) to avian influenza virus (aH5N1). Anti-H2N2 HA IgG antibody was also detected in the cell culture supernatants in a significant level after LAIV stimulation (mean ± SE: 0.93 ± 0.23, p < 0.01). High levels of anti-sH3N2 HA IgG antibody was discovered after LAIV stimulation of tonsillar MNCs, (mean ± SE: 1.2 ± 0.23p < 0.01). The current model of human nasal-associated lymphoid tissue (NALT) to evaluate B cells responses to LAIV was evident that it is a successful model to study future intranasal vaccines.

The Clinical Advances of Oncolytic Viruses in Cancer Immunotherapy.

A promising future for oncology treatment has been brought about by the emergence of a novel approach utilizing oncolytic viruses in cancer immunotherapy. Oncolytic viruses are viruses that have been exploited genetically to assault malignant cells and activate a robust immune response. Several techniques have been developed to endow viruses with an oncolytic activity through genetic engineering. For instance, redirection capsid modification, stimulation of anti-neoplastic immune response, and genetically arming viruses with cytokines such as IL-12. Oncolytic viral clinical outcomes are sought after, particularly in more advanced cancers. The effectiveness and safety profile of the oncolytic virus in clinical studies with or without the combination of standard treatment (chemotherapy, radiotherapy, or primary excision) has been assessed using response evaluation criteria in solid tumors (RECIST). This review will comprehensively outline the most recent clinical applications and provide the results from various phases of clinical trials in a variety of cancers in the latest published literature.

Declined Humoral Immunity of Kidney Transplant Recipients to SARS-CoV-2 Vaccines.

Background: Kidney transplant recipients (KTRs) commonly suffer from impaired immunity. KTRs' compromised immune response to COVID-19 vaccines indicates urgent revision of immunisation policies. Methods: A cross-sectional study was conducted in Madinah, Saudi Arabia of 84 KTRs who had received at least one dose of a COVID-19 vaccine. ELISA was used to evaluate anti-spike SARS-CoV-2 IgG and IgM antibody levels in blood samples obtained one month and seven months after vaccination. Univariate and multivariate analyses were performed to identify associations between seropositive status and factors such as the number of vaccine doses, transplant age, and immunosuppressive therapies. Results: The mean age of KTRs was 44.3 ± 14.7 years. The IgG antibody seropositivity rate (n=66, 78.5%) was significantly higher than the seronegativity rate (n=18, 21.4%) in the whole cohort (p<0.001). In KTRs seroconverting after one month (n=66), anti-SARS-CoV-2 IgG levels declined significantly between one month (median [IQR]:3 [3-3]) and seven months (2.4 [1.7-2.6]) after vaccination (p<0.01). In KTRs with hypertension, IgG levels significantly decreased between one and seven months after vaccination (p<0.01). IgG levels also decreased significantly in KTRs with a transplant of >10 years (p=0.02). Maintenance immunosuppressive regimens (triple immunosuppressive therapy and steroid-based and antimetabolite-based regimens) led to a significant decrease in IgG levels between the first and second sample (p<0.01). KTRs receiving three vaccine doses showed higher antibody levels than those receiving a single dose or two doses, but the levels decreased significantly between one (median [IQR]: 3 [3-3]) and seven months (2.4 [1.9-2.6]) after vaccination (p<0.01). Conclusion: KTRs' humoral response after SARS-CoV-2 vaccination is dramatically inhibited and wanes. Antibody levels show a significant decline over time in KTRs with hypertension; receiving triple immunosuppressive therapy or steroid-based or antimetabolite-based regimens; receiving mixed mRNA and viral vector vaccines; and with a transplant of >10 years.

Serostatus and Epidemiological Characteristics for Atypical Pneumonia Causative Bacteria among Healthy Individuals in Medina, Saudi Arabia, a Retrospective Study.

Background: Community-acquired atypical pneumonia is generally a mild and self-limiting infection. Still, it may lead to hospitalization and progressive clinical complications in some cases, particularly among the elderly and individuals with chronic diseases. Chlamydia pneumoniae, Legionella pneumophila, and Mycoplasma pneumoniae are the community's main causative agents of atypical pneumonia. However, most published studies evaluated their incidence in the hospital setting, and little is known about their prevalence among healthy individuals. This work aims to assess the seroprevalence of these bacteria among healthy people to determine the status of immunity against these bacteria in the community. Methodology: Two hundred and eighty-three serum samples from a multicenter in Medina, Saudi Arabia, were collected in this study. Serum samples were subjected to indirect enzyme-linked immunosorbent assays (ELISAs) to detect IgG antibodies against C. pneumoniae, L. pneumophila, and M. pneumoniae to investigate the seroprevalence of these bacteria and their distribution among different genders and age groups of healthy people. Results: IgG seropositivity for at least one of the three atypical pneumonia-causative bacteria occurred in 85.8% (n= 243/283) of the sample population. IgG seropositivity for C. pneumoniae occurred in 80.6% (228/283) of the population, followed by 37.5% for L. pneumophila and 23% for M. pneumoniae (66/283). In addition, the IgG seropositivity rates for the three bacteria were observed predominantly among male participants. Furthermore, no significant difference in IgG seropositivity distribution occurred between different age groups of healthy people for C. pneumoniae, L. pneumophila and M. pneumoniae. Conclusions: The current study found that C. pneumoniae, L. pneumophila, and M. pneumoniae tended to be highly prevalent among healthy people and more common among males than females. Additionally, their pattern of distribution among healthy individuals seemed to be predominant among young adults (aged 20−40 years), which differs from their predominant distribution among elderly patients in hospital settings (>50 years).

Acute Helicobacter pylori Infection Prevalence Among Renal Failure Patients and Its Potential Roles with Other Chronic Diseases: A Retrospective Cohort Study.

Background: Helicobacter pylori (H. pylori) infection is relevant to several chronic human diseases, from digestive diseases to renal, metabolic, and cancer diseases. H. pylori infections and chronic kidney diseases are in increasing, global records; if not well controlled in a specific population, these diseases might lead to more clinical complications. Methods: In this retrospective study, we investigated the prevalence of acute H. pylori infections among 127 dialysis patients via subjecting their serums to the enzyme-linked immunosorbent assay (ELISA) to detect the human Immunoglobulin M (IgM) against H. pylori infections. Samples were from dialysis patients in a single hemodialysis center in Medina, Saudi Arabia, from January to August 2021. Results: Our results indicated the significant prevalence of H. pylori acute infections among 33.1% of renal failure patients recruited in this study, chi-squared: 14.559, p-value: 0.0001. In addition, no significant occurrence of acute H. pylori infection among males and females, chi-squared: 1.823, p-value: 0.177. Furthermore, the prevalence of acute H. pylori infection was not significant in different age groups of renal failure patients. Chi-squared: 6.803, p-value: 0.147, despite H. pylori-infected cases predominantly represented in patients above 51 years. Moreover, we noticed that hypertension, followed by diabetes, was the most prevalent underlying medical condition among acute infected H. pylori and renal failure patients. Conclusion: We documented the significant prevalence of acute H. pylori infection among renal failure patients. We also highlighted and discussed the possible potential roles of H. pylori in renal failure and other chronic diseases. Routine screening and treatment for acute H. pylori infection for chronic kidney diseases, hypertension, and diabetes patients would positively reduce the bacterium's progressive effects on them. They might even improve the control of these diseases.

Unexpected Detection of Anti-SARS-CoV-2 Antibodies Before the Declaration of the COVID-19 Pandemic.

Background: Limited information is currently available regarding the global incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections prior to the declaration of the coronavirus disease 2019 (COVID-19) pandemic, which may result in improper conclusions regarding the timing of viral transmission. Methods: We investigated the presence of specific antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 in archived serum samples that were collected from 478 healthy blood donors and patients in Madinah, Saudi Arabia, between October 2019 and January 2020. Enzyme-linked immunosorbent assay (ELISA) was performed to measure SARS-CoV-2 IgM and IgG antibodies. In addition, rheumatoid factor (RF) and urea dissociation tests were performed in all samples, which showed seropositivity for the SARS-CoV-2 IgM antibody. Additionally, Chemiluminescence immunoassays (CLIA) targeting the RBD of the SARS-CoV-2 spike (S) protein were performed to confirm the seropositivity of the samples. Results: Overall, 20 (4.18%) serum samples were detected by ELISA to have SARS-CoV-2 IgG or IgM antibodies. Of these, 12 (2.51%) samples were positive for IgM antibody, and 8 (1.67%) were positive for IgG antibody. The 12 samples positive for SARS-CoV-2 IgM antibody were subjected to RF and urea dissociation tests, and all samples were RF-negative. The ELISA results were negative for 7 (58.33%) samples when subjected to urea dissociation prior to ELISA, whereas the other 5 (41.67%) samples remained positive. These 5 samples remained positive for the anti-S RBD IgG antibody in the CLIA. In addition, 3 of the 8 samples with IgG positivity according to the ELISA remained positive in the CLIA. After reviewing their data, we discovered that the 8 CLIA-confirmed positive samples were obtained from returned travellers who had visited China during the 4-week period immediately preceding blood donation. Conclusion: In conclusion, we found evidence to support the early circulation of SARS-CoV-2 among persons who visited China a few months prior to the pandemic declaration. These results can be used to better define the spread of SARS-CoV-2 infections before the COVID-19 pandemic declaration. The detection of SARS-CoV-2 antibodies in individuals before the pandemic was declared in China could rewrite the pre-pandemic timeline.

Rubella Humoral Immunity Among the Saudi Population of Madinah in the Western Region of Saudi Arabia.

Maintaining herd immunity against the rubella virus is important for controlling the spread and recurrence of rubella. Rubella vaccination for children has been affordable in Saudi Arabia since 1982. To assess the immune response derived from vaccination, we assessed the seroprevalence against the rubella virus among the population of the Madinah region. An indirect enzyme-linked immunosorbent assay (ELISA) was used to measure anti-rubella IgG antibodies in 791 serum samples obtained from 336 (42.5%) men and 455 (57.5%) women, ranging from 14 to 49 years in age. Among all participants, 94.2% were seropositive for rubella IgG antibodies, indicating a high degree of immunization. However, 5.8% of participants were seronegative, suggesting a population of either poor vaccine responders or the potential risk of waning vaccine-induced immunity. No significant difference or association with rubella seropositivity was identified according to age, sex, or pregnancy status. The median anti-rubella IgG antibody concentrations differed significantly between age groups (p < 0.001). Although a high percentage of the tested population in Madinah demonstrated anti-rubella IgG antibody seropositivity, a notable percentage of the population were seronegative, making them susceptible to infection.

Seroprevalence of SARS-Cov-2 IgG antibodies in patients at a single center in Saudi Arabia.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has had a massive impact on public health as well as the economy. Understanding the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among undiagnosed individuals is important for developing an informed pandemic response. OBJECTIVE: Investigate the prevalence of undiagnosed COVID-19 disease. DESIGN: Cross-sectional. SETTING: Tertiary care center in Madinah, Saudi Arabia. SUBJECTS AND METHODS: All participants were on follow-up visits to various clinics and had not been previously diagnosed with COVID-19. Enzyme-linked immunosorbent assay was used to specifically assess the anti-spike IgG antibody seropositivity in serum samples. We associated the seropositivity rates of the participants with age, body mass index (BMI), nationality, blood groups, and sex with uni- and multivariate analyses. MAIN OUTCOME MEASURES: Seropositivity for IgG anti-spike antibodies against SARS-CoV-2. SAMPLE SIZE AND CHARACTERISTICS: 527 subjects, with a median (interquartile percentiles) age of the 527 subjects was 34 (24-41). RESULTS: Of the 527 samples, about one-fourth (n=124, 23.5%) were positive for anti-spike IgG antibody against SARS CoV-2. Age was associated with anti-spike IgG antibody positivity (P<.002). Participants >30 years were more likely to be seropositive (28-29%) than younger participants (15.4%). Additionally, seropositivity was associated with female gender (P<.001) and a higher BMI (P<.006). In the multivariate logistic regression, age >30, female gender and BMI >40 were associated with seropositivity. CONCLUSION: The percentage of seropositive individuals reflects the high level of undiagnosed COVID-19 patients among the population. Our results will help in a better evaluation of the public health measures applied during the COVID-19 pandemic and any future public health crises. LIMITATIONS: Sample size was small, single-center study and no rural areas were included. CONFLICT OF INTEREST: None.

Human Cytomegalovirus Seroprevalence Among Blood Donors in the Madinah Region, Saudi Arabia.

Background and objective Human cytomegalovirus (HCMV), a double-stranded DNA virus of the Herpesviridae family, can remain latent for long periods of time. HCMV may cause severe illness in immunocompromised patients and is associated with congenital anomalies. This study aimed to determine the anti-HCMV immunoglobulin G (IgG) and IgM antibody seroprevalence among blood-donating Saudi men in the Madinah region. Methods A total of 375 blood-donating Saudi men were recruited from the Central Blood Bank in Madinah, the Kingdom of Saudi Arabia (KSA), and stratified into three age groups: 18-30, 31-40, and 41-61 years. Anti-HCMV IgG and IgM antibody levels were measured by enzyme-linked immunosorbent assay (ELISA). Pearson's correlation coefficient was used to correlate antibody levels with variables. Results Most of the tested samples (95.73%, n=356) were positive for anti-HCMV IgG antibodies, but only 1.6% (n=6) were positive for both IgM and IgG antibodies, and all of them belonged to the age groups of 31-40 and 41-61 years. A strong inverse correlation was found between anti-HCMV IgG antibody levels and age (r=-0.51, p<0.0001). Additionally, there was an inverse correlation between anti-HCMV IgG antibody levels and body mass index (BMI) (r=-0.11, p=0.036). No correlations were found between anti-HCMV IgG levels and hemoglobin levels or blood groups of the participants. Conclusions Blood-donating Saudi men in Madinah had a high seroprevalence of anti-HCMV IgG antibodies, indicating previous viral exposure. Age and BMI might influence the humoral immunologic memory response against HCMV, which appears to be endemic in Madinah.

A Single Dose of SARS-CoV-2 Vaccine Primes a Strong Humoral Immune Response in COVID-19-Recovered Patients.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes coronavirus disease 2019 (COVID-19), which has affected hundreds of millions of people globally. The development of safe and effective vaccines represents an urgent demand. A total of 136 participants were recruited in this study, including 75 men and 61 women. The participants were divided into two groups: those who were virus naïve (never infected) and those who had recovered from COVID-19. Each group included individuals who received either the Pfizer-BioNTech BNT162b2 mRNA or the Oxford-AstraZeneca ChAdOx1 COVID-19 vaccine. Enzyme-linked immunosorbent assay (ELISA) was used to measure anti-S IgG antibody concentrations in sequential serum samples obtained before vaccine administration, after the first vaccine dose, and after the second vaccine dose. We compared the antibody responses of individuals with confirmed prior COVID-19 infection with those of individuals without prior evidence of infection. All participants who were previously infected with SARS-CoV-2 who received one dose of either the Pfizer-BioNTech BNT162b2 mRNA or the Oxford-AstraZeneca ChAdOx1 COVID-19 vaccine showed significant anti-S IgG antibody levels. No sex-related differences were observed when we compared antibody levels between men and women. In infection-naïve participants ≥60 years, a second vaccine dose was necessary to achieve higher levels of antibody when comparing the IgG antibody levels after receiving the first and second dose.

Reactogenicity and Immunogenicity of the Pfizer and AstraZeneca COVID-19 Vaccines.

Background: The relationships of the coronavirus disease 2019 (COVID-19) vaccination with reactogenicity and the humoral immune response are important to study. The current study aimed to assess the reactogenicity and immunogenicity of the Pfizer and AstraZeneca COVID-19 vaccines among adults in Madinah, Saudi Arabia. Methods: A cross-sectional study, including 365 randomly selected adult Pfizer or AstraZeneca vaccine recipients who received a homologous prime-boost vaccination between February 1st and June 30th, 2021. Data of height and weight were collected to assess the weight status of percipients. An evaluation of seropositivity for anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies was assessed using enzyme-linked immunosorbent assay (ELISA). Results: Among the participants, 69% (n = 250) reported at least one vaccine-related symptom. Pain at the injection site was the most frequently reported vaccine-related symptom. The mean total score for vaccine-related symptoms was significantly higher among participants who received the AstraZeneca vaccine, women, and participants with no previous COVID-19 infection (p < 0.05). Spike-specific IgG antibodies were detected in 98.9% of participants after the receipt of two vaccine doses, including 99.5% of Pfizer vaccine recipients and 98.3% of AstraZeneca vaccine recipients. Significantly, higher proportions of participants in the <35-year age group developed a humoral immune response after the first vaccine dose compared with the participants in other age groups. Conclusion: Participants who received the Pfizer COVID-19 vaccine reported fewer vaccine-related complications compared with those who received the AstraZeneca COVID-19 vaccine, but no serious side effects were reported in response to either vaccine. Health status and age were factors that may influence COVID-19 vaccine effectiveness for the generation of antibodies against the SARS-CoV-2 spike protein.

TLR8 is highly conserved among the Saudi population and its mutations have no effect on the severity of COVID-19 symptoms.

Coronavirus 2019 (COVID-19) is an infection caused by the newly discovered severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The innate system is the first line of defense against pathogens and diverse infectious agents. It has been suggested to play a key role in the development of the cytokine storm and promoting other severe forms of chronic inflammation. Toll-like receptors (TLRs) are crucial for the innate immune response to pathogens. TLR8 is expressed on myeloid cells and phagocytes, where it acts as an endosomal sensor of RNA degradation. The present study aimed to investigate whether the severity of COVID-19 symptoms could be associated with certain genetic variations of TLR8. We collected blood samples from 45 participants who had moderate to severe respiratory symptoms and a positive COVID-19 PCR test result within 3-5 days of sample collection. Genomic DNA was extracted from the blood samples, then exon 2 of the TLR8 gene was amplified with polymerase chain reaction (PCR), and PCR products were utilized for sequencing. DNA sequencing showed an average of 99.63% sequence homology in TLR8 across all samples. Base-pair homology analysis revealed variations in TLR8 at two positions: X:12937804 (rs5744080) and X:12937513 (rs2159377). The results revealed that these two mutations had no detrimental effect on symptoms in the target population. Our results show that specific SNPs did not affect the final receptor function of TLR8. This finding also indicates that the innate immune response, once activated, does not depend on the innate immune receptor's level of affinity for identifying their respective glycoprotein structures on the SARS-CoV-2 virus.

Assessment of SARS-CoV-2 Anti-Spike IgG Antibody in Women and Children in Madinah, Saudi Arabia: A Single-Center Study.

BACKGROUND: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Information on the prevalence of SARS-CoV-2 antibodies in women and children in Madinah has been limited. The current study aimed to evaluate SARS-CoV-2 IgG seropositivity among women and children at Madinah Maternity and Children's Hospital. METHODS: In this cross-sectional study, 579 participants were recruited between January and April 2021 from Madinah Maternity and Children's Hospital, Saudi Arabia. Data concerning age, sex (for children), blood group, and height and weight (for women) were collected from the hospital database. SARS-CoV-2 anti-spike (anti-S) IgG antibodies were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: Over 58% of children (n = 195), including 60% of children ≤ 1 year (n = 75), and 50.2% (n = 124) of women were SARS-CoV-2 anti-S IgG seropositive. Significantly higher anti-S IgG levels were observed in children than in women (0.78 ± 1.05 vs. 0.65 ± 0.98, p = 0.008). Compared with women, children had higher odds of high SARS-CoV-2 anti-S IgG levels (odds ratio: 1.41; 95% confidence interval: 1.01-1.97; p = 0.041). No significant associations were observed for anti-S IgG levels with age in women or children or with body mass index among women. CONCLUSION: Non-reported COVID-19 infections were more prevalent among children than women, and non-reported COVID-19 infections children represent a viral transmission risk; therefore, increased screening, especially among school-aged children, may represent an important COVID-19 preventive control measure.

Infection with SARS-CoV-2 primes immunological memory in human nasal-associated lymphoid tissue.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, has resulted in considerable morbidity and mortality in humans. Little is known regarding the development of immunological memory following SARS-CoV-2 infection or whether immunological memory can provide long-lasting protection against reinfection. Urgent need for vaccines is a considerable issue for all governments worldwide. METHODS: A total of 39 patients were recruited in this study. Tonsillar mononuclear cells (MNCs) were co-cultured in RPMI medium and stimulated with the full-length SARS-CoV-2 spike protein in the presence and absence of a CpG-DNA adjuvant. An enzyme-linked immunosorbent assay (ELISA) was utilised to measure the specific antibody response to the spike protein in the cell culture supernatants. RESULTS: The SARS-CoV-2 spike protein primed a potent memory B cell-mediated immune response in nasal-associated lymphoid tissue (NALT) from patients previously infected with the virus. Additionally, spike protein combined with the CpG-DNA adjuvant induced a significantly increased level of specific anti-spike protein IgG antibody compared with the spike protein alone (p < 0.0001, n = 24). We also showed a strong positive correlation between the specific anti-spike protein IgG antibody level in a serum samples and that produced by MNCs derived from the same COVID-19-recovered patients following stimulation (r = 0.76, p = 0.0002, n = 24). CONCLUSION: Individuals with serological evidence of previous SARS-CoV-2 exposure showed a significant anti-spike protein-specific memory humoral immune response to the viral spike protein upon stimulation. Additionally, our results demonstrated the functional response of NALT-derived MNCs to the viral spike protein. CpG-DNA adjuvant combined with spike protein induced significantly stronger humoral immune responses than the spike protein alone. These data indicate that the S protein antigen combined with CpG-DNA adjuvant could be used as a future vaccine candidate.