Seroprevalence and factors associated with SARS-CoV-2 infection among healthcare workers: cross-sectional study.

BACKGROUND: Healthcare workers (HCWs) are at a higher risk of contracting COVID-19 due to their close contact with infected patients. However, the true burden of COVID-19 among HCWs in Yemen is unknown due to the inadequate availability of healthcare and the subclinical nature of the disease. This study aims to estimate the seroprevalence of SARS-CoV-2 infection among HCWs in two Yemeni governorates and identify associated factors using a cross-sectional design. METHOD: A total of 404 HCWs were surveyed from June 2022 to September 2022 in Lahj and AL-Dhalea hospitals. A self-administered questionnaire collected demographic data, COVID-19 infection history, and vaccination status. A total of 404 human sera were tested using a specific electrochemiluminescence immunoassay assay. Association analysis was conducted to identify associations between antibody prevalence and demographic and vaccine-related variables. RESULT: The median age of the HCWs was 31 (Range 20-64) years, with 65.0% being male and 35.0% female. Of all HCWs, 94% were SARS-CoV-2 seropositive and 77.0% had no confirmed test of COVID-19-related symptoms. There was no significant association between seropositivity and demographic factors such as age, gender, occupation, or COVID-19 vaccination (P > 0.05). CONCLUSION: The seroprevalence of SARS-CoV-2 was high among HCWs in Yemen, primarily due to natural infection rather than vaccination. Compliance with infection prevention and control measures did not significantly affect seropositivity. This study highlights the need for improved healthcare systems and resources to reduce the burden of COVID-19 and promote infection prevention and control (IPC) measures among HCWs in Yemen.

Association between Hepatitis C Virus Viremia and the rs12979860, rs2228145 and rs1800795 SNP (CT/AC/GG) Genotype in Saudi Kidney Transplant Recipients.

BACKGROUND: Hepatitis C virus (HCV) is a major health problem, particularly in high-risk groups such as kidney transplant recipients, where it can adversely affect graft survival and increase the relative risk for mortality. Recently, the role of genetic variation among HCV patients in determining the outcome of infections has been under investigation. OBJECTIVE: To investigate the association of single-nucleotide polymorphisms (SNPs) rs12979860 (located within the interleukin-28B locus), rs2228145 (interleukin-6 receptor) and rs1800795 (interleukin-6 promoter) with HCV viremia in renal transplant patients. MATERIALS AND METHODS: In this analytical cross-sectional study, 149 kidney transplant recipients, 82 males (median age: 41 years) and 67 females (median age: 45 years), were screened for HCV RNA in blood using real-time polymerase chain reaction and genotyped by sequencing (rs12979860) and restriction fragment length polymorphism (rs2228145 and rs1800795). RESULTS: HCV RNA was detected in 17 (11.41%) of the 149 patients. There was no statistically significant association between the studied SNPs and HCV viremia. However, a combination of the CT/AC/GG genotype was significantly associated with HCV viremia (odds ratio: 5.4). The genotype AA of rs2228145 in the IL-6 receptor was associated with viremia levels of >105 copies/ml (odds ratio: 5.96). CONCLUSION: To the best of the authors' knowledge, this is the first study that has shown that the CT/AC/GG genotype has an impact on HCV viremia in kidney transplant patients. Therefore, such SNP genotypes may potentially be used to identify transplant patients at risk of HCV infection.

Prevalence of serological markers and nucleic acid for blood-borne viral infections in blood donors in Al-Baha, Saudi Arabia.

INTRODUCTION: Data on blood-borne viral infections in some regions in Saudi Arabia remain scarce. This study investigates the prevalence of serological markers and nucleic acid for blood-borne viruses among blood donors in Al-Baha, Kingdom of Saudi Arabia. METHODOLOGY: In this cross-sectional study, 2,807 donors who donated blood between January 2009 and November 2011 were investigated for blood-borne viral serological markers including HBsAg, anti-HBc, anti-HBs, anti-HCV, anti-HIV, and anti-HTLVI/III in addition to viral nucleic acid. RESULTS: All donors were males between 16 to 66 years of age (mean: 31.5 ± 9.3 years). Viral nucleic acid and/or serological markers were detected in a total of 36 (1.3%) donors; of them, 26 (72.2%) had nucleic acid concomitant with serological markers, 6 (16.7%) had only viral nucleic acid, while 4 (11.1%) had only serological markers. Of all donors, 22 (0.8%) had HBsAg, 227 (8.0%) had anti-HBc, 157 (5.0%) had anti-HBs, 2,577 (91.8%) had no HBV markers, 2 (0.07%) had anti-HIV, 1 (0.04%) had anti-HCV, and 1 (0.04%) had anti-HTLVI/II. The donors who were born during HBV vaccination era showed no HBsAg (0.0%; p = 0.052), lower rates of anti-HBc (1.5%; p < 0.001) and anti-HBs (0.7%; p < 0.001), while the majority had no HBV markers (98.5%; p < 0.001). CONCLUSIONS: Combined viral nucleic acid and serological testing of donated blood enhances blood safety. The absence of HBV markers among donors suggests susceptibility or declined anti-HBs levels. Thus, HBV revaccination or a vaccine boost among adolescents and adults might be indispensable.

In Vitro Apoptosis Triggering in the BT-474 Human Breast Cancer Cell Line by Lyophilised Camel's Milk.

Breast cancer is a global health concern and is a major cause of death among women. In Oman, it is the most common cancer in women, with an incidence rate of 15.6 per 100,000 Omani females. Various anticancer remedies have been discovered from natural products in the past and the search is continuing for additional examples. Cytotoxic natural compounds may have a major role in cancer therapy either in potentiating the effect of chemotherapy or reducing its harmful effects. Recently, a few studies have reported advantages of using crude camel milk in treating some forms of cancer. However, no adequate data are available on the lyophilised camel's milk responsibility for triggering apoptosis and oxidative stress associated with human breast cancer. The present study aimed to address the role of the lyophilised camel's milk in inducing proliferation repression of BT-474 and HEp-2 cells compared with the non-cancer HCC1937 BL cell line. Lyophilized camel's milk fundamentally repressed BT-474 cells growth and proliferation through the initiation of either the intrinsic and extrinsic apoptotic pathways as indicated by both caspase-3 mRNA and its action level, and induction of death receptors in BT-474 but not the HEp-2 cell line. In addition, lyophilised camel's milk enhanced the expression of oxidative stress markers, heme-oxygenase-1 and reactive oxygen species production in BT-474 cells. Increase in caspase-3 mRNA levels by the lyophilised camel's milk was completely prevented by the actinomycin D, a transcriptional inhibitor. This suggests that lyophilized camel's milk increased newly synthesized RNA. Interestingly,it significantly (p<0.003) repressed the growth of HEp-2 cells and BT-474 cells after treatment for 72 hours while 24 hours treatment repressed BT-474 cells alone. This finding suggests that the lyophilised camel's milk might instigate apoptosis through initiation of an alternative apoptotic pathway.

Fluctuation in the Levels of Immunoglobulin M and Immunoglobulin G Antibodies for Cardiolipin and ß2-Glycoprotein among Healthy Pregnant Women.

OBJECTIVES: Antiphospholipid antibodies fluctuate during a healthy normal pregnancy. This study aimed to investigate the levels of both immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies for cardiolipin and ß2-glycoprotein (ß2GP) among healthy pregnant women. METHODS: This study was conducted between May 2010 and December 2012. A total of 75 healthy Omani pregnant women with no history of autoimmune disease were investigated during their pregnancy and 90 days after delivery at the Armed Forces Hospital in Muscat, Oman. A control group of 75 healthy Omani non-pregnant women were also investigated as a comparison. Levels of IgM and IgG antibodies for both anti-cardiolipin antibodies (ACAs) and ß2GP were measured using a standard enzyme-linked immunosorbent assay. RESULTS: The ACA IgM levels were significantly higher in the control group compared to the pregnant women (P <0.001). No significant differences were observed in the ACA IgM levels between the control group and the pregnant women after delivery. In contrast, ACA IgG levels were significantly higher during pregnancy and after delivery compared with those of the healthy control group (P = 0.007 and 0.002, respectively). The levels of ß2GP IgG were significantly higher during pregnancy than after delivery and in the control group (P = 0.001 and <0.001, respectively). CONCLUSION: In this study, ACA IgG levels increased during healthy pregnancies and after normal deliveries whereas ß2GP IgG levels increased transiently during the pregnancies. Both phenomena were found to be significantly associated with a transient decline in the levels of IgM specific for these antigens. Therefore, the levels of these antibodies may be regulated during a healthy pregnancy.

Immune response to Hepatitis B vaccine among children in Yemen.

OBJECTIVE: This study looks into the immune response to hepatitis B vaccine (HBV) among children who completed the 3 doses of vaccine 7-years after inclusion of HBV vaccination to the National Extended Program for Immunizations (EPI) in Yemen. METHODS: Between March 2002 and October 2002, a total of 170 children, aged 13-73 months with a mean age of 43.64 +/- 17.42 SD months; and have completed the 3 HBV vaccine doses were investigated for immune response to HBV vaccine by quantifying anti-HBs. Past infection was investigated by testing children to total anti-HBc. RESULTS: Of all children, 49.4% were males and 50.6% were females. One hundred and forty-two (83.5%) responded to the vaccine (antibody level > or = 10 mIU/ml). Only 3 children of 153 (2%) were reactive to anti-HBc indicating that the response was due to vaccination rather than combined effect of vaccine and HBV past-infections. There was a trend of decreasing antibody level with an increasing age. However, the difference in antibody levels between age groups was not statistically significant (p=0.40). Significantly lower antibody level (p=0.02) was found among children with a low economic status. CONCLUSION: This study has revealed a high response rate to HBV vaccine. However, a considerable proportion (32.4%) of vaccinated children remains to be reconsidered for either revaccination or booster doses due to lack, inadequate or low response. The trend of decreasing antibody level with increasing age suggests a need of careful monitoring of HBV vaccine efficacy in Yemen. Demographic factors such as gender number of inhabitants per room and educational level of father did not significantly affect the immune response to HBV vaccine.

African links and hepatitis B virus genotypes in the Republic of Yemen.

Hepatitis B virus (HBV) genotypes in three different communities in the Republic of Yemen with and without significant African links were studied. The subjects included indigenous Yemeni blood donors (n = 987), Africans who had settled down in Yemen for several generations (n = 97) and Soqotrans living on an island in the Indian Ocean close to the African coast (n = 99). Phylogenetic analysis of HBV surface region sequences showed the presence of two major genotypes; A and D: sequences from the blood donors were all genotype D (17/17); those from Africans residing in Yemen were predominantly genotype D (7/8) although one sequence was genotype A; whereas a mixture of genotype A and D was found among the Soqotrans (5/8 and 3/8 respectively). Genotype A sequences were associated with higher viral load, but the difference was not statistically significant. Human migration and international travel, may lead to an interaction between HBV genotypes. The Republic of Yemen is at a location where genotypes A and D meet. The results from this study suggest that genotype A is found only in communities with continuing African links and that genotype D remains the dominant genotype in settled populations. More studies are needed to examine possible long-term changes in HBV genotypes in this region.

The significance of 'anti-HBc only' in the clinical virology laboratory.

BACKGROUND: Isolated detection of hepatitis B core antibody (anti-HBc) in the absence of surface antigen (HBsAg) or antibody (anti-HBs) has been reported, particularly among individuals infected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV). The significance of this phenomenon is unknown and it is unclear whether all individuals with such serological pattern need further molecular investigations. OBJECTIVES: To determine the prevalence of 'anti-HBc only' in samples referred to a clinical virology laboratory and to evaluate its significance and possible mechanisms. STUDY DESIGN: Samples identified as anti-HBc positive (389/4359, 8.9%) during an 11-month period were investigated for HBsAg, anti-HBs, anti-HCV and anti-HIV. 'Anti-HBc only' samples were tested for HBV DNA using a nested qualitative PCR. Viral loads were measured in samples with detectable HBV DNA and the DNA sequences were analysed. RESULTS: Of 379 samples with detectable anti-HBc, 155 (40.9%) were 'anti-HBc only'. HBV DNA was detected in 6/151 (4%), all of which had a viral load <400 copies per ml. Anti-HIV was found in 50/151 (33.1%) and anti-HCV in 14/151 (9.3%). Of these, only one of the HIV infected patients had detectable HBV DNA. Phylogenetic analysis of the HBV surface gene from three patients showed a variety of genotypes (A, E and G). One sequence had a mutation in codon 144, which has previously been reported to give false negative HBsAg results. CONCLUSIONS: 'Anti-HBc only' is a common phenomenon in the clinical virology laboratory but only a small proportion of samples had detectable HBV DNA. The presence of HBsAg mutants with possible false negative HBsAg test result is of concern. Samples with 'anti-HBc only' could be used to monitor the emergence of these mutants.

Chlamydia trachomatis infections among Yemeni school pupils in relation to environmental conditions.

OBJECTIVE: This study is aimed at establishing the prevalence of Chlamydia trachomatis infections among school pupils in Sana'a, Republic of Yemen, and to explore the association of infection with environmental and social factors. METHODS: A total of 787 school children, 529 boys and 258 girls, were randomly selected for enrollment in this study. Four hundred and twenty-nine were from 4 schools in Sana'a city, and 358 from 3 rural schools around Sana'a, Republic of Yemen. Questionnaire forms were filled in for each child to investigate environmental and social factors. Sera were tested for anti Chlamydia trachomatis IgG antibodies using enzyme-linked immunosorbent assay CTM-IgG . RESULTS: An overall rate of infection of 45.9% was determined. The rate of infection among rural pupils (73.2%) was higher (P<0.0001) than that among urbanones (23.1%). The rate of infection was found significantly (P<0.001) inversely correlated with age of the pupils. Environmental factors which were found to influence the infection rate were; rural residence, unplastered walls, mud floor, lack of stand pipe water, lack of latrine and presence of animals within dwelling with odds ratio of 9.1, 6.3, 6.1, 5.2, 3.7, 3.5 and 1.7. Also, the male sex and illiteracy of the parents has been found to be risk factors for infection. CONCLUSION: Prevalence of Chlamydia trachomatis infection was found to be high. The prevalence correlates inversely with age. Rural residence, environmental conditions and social factors were risk factors for infections. Yemen could be identified as a trachoma endemic area, which should be targeted by the control programs.

Increase in susceptibility of young adults to hepatitis B infection in the Republic of Yemen.

Susceptibility to hepatitis B virus (HBV) infection among 987 young adult male blood donors in 2 major Yemeni cities was investigated. Hepatitis B surface antigen (HBsAg) was detected in 10.8% (107/987) of donors and 284 (28.8%) had evidence of ongoing or past HBV infection. Hepatitis B surface antibody (anti-HBs) only was detected in 34 (3.4%) donors. Thus, 67.8% (669/987) of donors had no detectable HBV-markers indicating susceptibility to infection. The proportion of HBV-susceptible donors decreased from 70.9% (249/351) in donors aged < 25 years to 69.4% (334/481) in those aged 25-34 years and 55.5% (86/155) in donors aged > 34 years (P = 0.002). The high proportion of susceptible young adults in a community with a high HBsAg carrier rate could be the result of changing epidemiology of hepatitis B in Yemen. Consideration should therefore be given to immunizing young adults as an adjunct to the current expanded infant immunization programme.

Two distinct types of hepatitis B virus core promoter variants in Yemeni blood donors.

Genetic variations in the basic core promoter (BCP) region of hepatitis B virus (HBV) occur during the natural history of chronic HBV infection. This study investigates the presence of basic core promoter variations in 28 asymptomatic Yemeni blood donors, correlating variations with HBeAg phenotype and viral load. The core promoter/precore and surface gene region of HBV DNA were amplified using nested PCRs and the PCR products were sequenced either directly or after cloning. HBeAg and viral load were measured when HBV DNA was detectable. Sequencing of 18 surface PCR products indicated that all were of genotype D. Two distinct types of variants were identified in the basic core promoter: substitution only (N = 14) and major deletion (N = 9). The commonest substitutions were located at nucleotide positions 1753, 1762, and 1764; 10/14 (71.4%) were associated with the precore 1896A substitution resulting in the premature stop of the precore reading frame and 6/14 (42.9%) had viral loads above 400 copies/ml. Two forms of deletion variants were found: 8 bp deletion (1763-1770) (N = 2) and a novel 12 (1746-1757) + 8 bp (1763-1770) deletion (N = 7). The deletion sequences were never associated with the precore 1896A substitution and all had viral load below 400 copies/ml with negative HBeAg phenotype. The polymorphism 1773C was found in 9/14 (64.3%) substitution sequences whereas all deletion sequences had 1773T. Two donors had mixed sequences of basic core promoter substitution and major deletions (both 8 bp and 12 + 8 bp). While the deletion variants in these two donors were similar to others found in isolation, the substitutions were of a different pattern. Further studies are required to understand the selection process behind these variants.