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.

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.

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.

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).

Seroprevalence of community-acquired atypical bacterial pneumonia among adult COVID-19 patients from a single center in Al Madinah Al Munawarah, Saudi Arabia: A retrospective cohort study.

OBJECTIVES: To investigate the seroprevalence of the community-acquired bacterial that causes atypical pneumonia among confirmed severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) patients. METHODS: In this cohort study, we retrospectively investigated the seroprevalence of Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila among randomly selected 189 confirmed COVID-19 patients at their time of hospital presentation via commercial immunoglobulin M (IgM) antibodies against these bacteria. We also carried out quantitative measurements of procalcitonin in patients' serum. RESULTS: The seropositivity for L. pneumophila was 12.6%, with significant distribution among patientsolder than 50 years (χ2 test, p=0.009), while those of M. pneumoniae was 6.3% and C. pneumoniae was 2.1%, indicating an overall co-infection rate of 21% among COVID-19 patients. No significant difference (χ2 test, p=0.628) in the distribution of bacterial co-infections existed between male and female patients. Procalcitonin positivity was confirmed amongst 5% of co-infected patients. CONCLUSION: Our study documented the seroprevalence of community-acquired bacteria co-infection among COVID-19 patients. In this study, procalcitonin was an inconclusive biomarker for non-severe bacterial co-infections among COVID-19 patients. Consideration and proper detection of community-acquired bacterial co-infection may minimize misdiagnosis during the current pandemic and positively reflect disease management and prognosis.

Low prevalence of community-acquired influenza coinfections among COVID-19 patients in Al-Madinah, Saudi Arabia: A retrospective cohort study.

BACKGROUND: Coinfections with respiratory viruses among SARS CoV-2 patients have been reported by several studies during the current COVID-19 pandemic. Most of these studies designated these coinfections as being hospital-acquired infections; however, there is inadequate knowledge about community-acquired respiratory coinfections among SARS CoV-2 patients. METHODS: In this retrospective cohort study, we investigated the seroprevalence of influenza A, influenza B, and parainfluenza-2 among newly hospitalized patients with confirmed COVID-19 infections (n = 163). The study was conducted during the early phase of the COVID-19 pandemic in Saudi Arabia (from April to October 2020). The patients' serum samples were subjected to commercial immunoglobulin M (IgM) antibody tests against the three aforementioned viruses. RESULTS: Seropositivity for influenza A and B and parainfluenza-2 occurred only in 4.2% (7/163) of COVID-19 patients, indicating simultaneous acute infections of these three viruses with SARS CoV-2 infection. All coinfection cases were mild and misdiagnosed during the care period in the hospital. CONCLUSION: This study highlights the low prevalence of community-acquired respiratory infections among COVID-19 patients in the current pandemic and we discussed the possible factors for this finding. During newly emerging epidemics or pandemics, considering other respiratory viruses circulating in the community is essential to avoid their misdiagnosis and account for their possible negative effects on pandemic disease management and prognosis.

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.

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.

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.

Serostatus of IgG antibody against mumps virus in adult population of Al Madinah Al Munawarah, Saudi Arabia.

OBJECTIVES: To determine the frequency and distribution of mumps-specific IgG antibodies among the healthy adult Saudi population in Al Madinah Al Munawarah, Saudi Arabia, where mandatory vaccination against measles-mumps-rubella (MMR) has been implemented for 30 years. METHODS: Qualitative and quantitative indirect enzyme-linked immunosorbent assay was performed to determine the mumps IgG antibody levels in sera collected from 429 individuals, including 224 men and 205 women. Participants were stratified into 3 age groups according to vaccination history (<20, 21-30, and >31 years). RESULTS: The overall seroprevalence of mumps antibodies in our population was 79.0%. The highest proportion of individuals with IgG antibody seropositivity, at 87.8% (95% confidence interval (95% CI): 84.7%-90.8%), was observed among the <20 years age group, who received 2 doses of vaccine. No significant relationships were observed between mumps seropositivity and age group or gender. The multivariable analysis identified the male gender and the age group >31 years as factors associated with an increased likelihood of seronegativity. Al Madinah Al Munawarah has achieved increased anti-mumps antibody seroprevalence since the implementation of the 2-dose MMR vaccination schedule. CONCLUSIONS: Based on our study findings, we recommend that serological screening be performed to assess the need for mumps vaccination among adults at high risk for exposure and transmission.

Seroprevalence against the measles virus after vaccination or natural infection in an adult population in Madinah, Saudi Arabia.

Background: Over the past few years, measles cases have increased worldwide, despite the availability of a safe and highly effective vaccine. Numerous countries have eliminated measles or have made substantial advancements toward elimination.Materials and Methods: This study investigated the seroprevalence of anti-measles antibodies and vaccination status among 362 men and 81 women in Madinah. All participants were vaccinated or acquired immunity naturally due to infection. We aimed to examine the persistence of anti-measles IgG antibodies, which were qualitatively and quantitatively determined using ELISA.Results: We showed that measles seropositivity (92%, n = 408) was significantly more frequent than negative (5.4%, n = 14) and equivocal results (2.5%, n = 11). Among men, 92.8% were seropositive for the anti-measles IgG antibody, whereas 88.9% of women were seropositive. In addition, a significant relationship was observed between age and measles seropositivity, with a significant positive correlation between age and anti-measles antibody concentration as assessed by Spearman's correlation analysis (r = 0.405, p < .001).Conclusion: Based on these results, observing the serological status of the population 20-38 y after vaccination may be necessary to minimize the proportion of individuals who may be vulnerable to contracting measles. Despite the efficacy of the measles, mumps, and rubella vaccine and the positive global impact associated with the use of this vaccine, including a general decline in measles cases, attention must still be paid to the issue of measles risk, and seronegative individuals should be identified and advised to receive a booster dose of the vaccine.

Effectiveness of COVID-19 Vaccines in Patients Under Maintenance Hemodialysis.

BACKGROUND: Several published data on the dialysis population showed that antibody levels decreased after COVID-19 vaccinations in comparison to the overall population. We aimed to illustrate the persistence of humoral response after receiving second dose of the Pfizer or AstraZeneca vaccines in patients under maintenance hemodialysis (HD). METHODS: A total of 119 adult patients on HD who were recruited from a single hemodialysis center in Madinah, Saudi Arabia. An enzyme-linked immunosorbent assay (ELISA) was utilized to measure the specific antibody response to the spike protein in the serum samples. RESULTS: Mean age of patients was 48.5 ± 13.5 years, while mean time since starting the renal dialysis was 5.09 ± 5.29 years. Blood samples were collected after 89.2 ± 25.7 days of receiving the second dose of the vaccines. A very high positive correlation between anti-S IgG antibodies in pre- and post-dialysis was found (rs= 0.93, p < 0.001). Additionally, there was a high positive correlation between anti-S IgG antibody collected at baseline and follow-up blood samples (30 days apart) (rs= 0.82, p < 0.001). Moreover, patients who received Pfizer had significantly higher mean change in anti-S IgG antibodies compared to patients who received AstraZeneca (0.41 ± 0.94 vs 0.03 ± 0.30, respectively, p = 0.026). CONCLUSION: The majority of the patients included in this study were able to yield an immune response to the vaccine after receiving the two doses. Persistence of IgG antibodies in the majority of the patients on HD in response to COVID-19 vaccines is encouraging in terms of continuing to vaccinate this category of patients in addition to monitoring them.

Natural immunity to influenza A and B among Saudi blood donors in Al Madinah Al Munawarah, Saudi Arabia.

OBJECTIVES:  To investigate the seroprevalence of influenza viruses (A and B) among blood donors in Kingdom of Saudi Arabia. Methods: The present investigation was conducted between April 2019 and July 2019. Participants were healthy adults recruited from the central blood bank Al Madinah Al Munawarah, Kingdom of Saudi Arabia. Immunoglobulin G (IgG) levels against influenza A and B were measured in serum samples using ELISA. RESULTS: The results showed that 29.2% of the sample had significant concentrations of influenza A IgG antibody, whereas 38.6% had significant concentrations of influenza B IgG antibody. A strong correlation was found between the levels of influenza A and influenza B antibodies (r=0.708, p less than 0.001). The number of individuals identified as negative for influenza A IgG antibody increased with age (p less than 0.01). In addition, no correlations were identified between influenza A IgG and influenza B IgG and body mass index (BMI), (p greater than 0.05). Finally, linear regression analysis showed that the level of influenza A antibody can be predicted by age (p less than 0.05) and body mass index (BMI) (p less than 0.05). CONCLUSION:  Approximately one-third of Saudi Arabian adults presented significant levels of influenza A and B antibodies in our study. Demographic factors, including age and BMI, might contribute to influenza A antibody levels.