Prevalence of measles antibodies among migrant workers in Singapore: a serological study to identify susceptible population subgroups.
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ABSTRACT: Background
In 2019, two clusters of measles cases were reported in migrant worker dormitories in Singapore. We conducted a seroprevalence study to measure the level of susceptibility to measles among migrant workers in Singapore.Methods
Our study involved residual sera of migrant workers from seven Asian countries (Bangladesh, China, India, Indonesia, Malaysia, Myanmar and the Philippines) who had participated in a survey between 2016 and 2019. Immunoglobulin G (IgG) antibody levels were first measured using a commercial enzyme-linked immunosorbent assay (ELISA) test kit. Those with equivocal or negative IgG results were further evaluated using plaque reduction neutralization test (PRNT).Results
A total of 2234 migrant workers aged 20-49 years were included in the study. The overall prevalence of measles IgG antibodies among migrant workers from the seven Asian countries was 90.5% (95% confidence interval 89.2-91.6%). The country-specific seroprevalence ranged from 80.3 to 94.0%. The seroprevalence was significantly higher among migrant workers born in 1965-1989 than those born in 1990-1999 (95.3% vs. 86.6%, p < 0.0005), whereas there was no significant difference by gender (90.8% in men vs. 89.9% in women, p = 0.508). 195 out of 213 samples with equivocal or negative ELISA results were tested positive using PRNT.Conclusion
The IgG seroprevalence in migrant workers was below the herd immunity threshold of 95% for measles. Sporadic outbreaks may occur in susceptible individuals due to high transmissibility of measles virus. Seroprevalence surveys can help identify susceptible subgroups for vaccination.
SUBMITTER: Ang LW
PROVIDER: S-EPMC8787927 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundSince the last local case of diphtheria in 1992, there had not been any case in Singapore until an autochthonous case was reported in 2017. This fatal diphtheria case of a migrant worker raised concerns about the potential re-emergence of locally transmitted toxigenic diphtheria in Singapore. We conducted a seroprevalence study to assess the immunity levels to diphtheria among migrant workers in Singapore.MethodsResidual sera from migrant workers who hailed from Bangladesh, China, India, Indonesia, Malaysia, Myanmar and the Philippines were tested for anti-diphtheria toxoid immunoglobulin G (IgG) antibodies. These migrant workers previously participated in a survey between 2016 and 2019 and had provided blood samples as part of the survey procedure.ResultsA total of 2176 migrant workers were included in the study. Their overall mean age was 27.1 years (standard deviation 5.0), range was 20-43 years. The proportion having at least basic protection against diphtheria (antitoxin titres ≥ 0.01 IU/ml) ranged from 77.9% (95% confidence interval [CI] 72.8 - 82.3%) among migrant workers from Bangladesh to 96.7% (95% CI 92.5 - 98.6%) in those hailing from Malaysia. The proportion showing full protection (antitoxin titres ≥ 0.10 IU/ml) ranged from 10.1% (95% CI 6.5 - 15.4%) in Chinese workers to 23.0% (95% CI 17.1 - 30.3%) in Malaysian workers. There were no significant differences in the proportion with at least basic protection across birth cohorts, except for those from Bangladesh where the seroprevalence was significantly lower in younger migrant workers born after 1989.ConclusionsThe proportions having at least basic protection against diphtheria in migrant workers from five out of seven Asian countries (India, Indonesia, Malaysia, Myanmar and the Philippines) were higher than 85%, the threshold for diphtheria herd immunity. Seroprevalence surveys should be conducted periodically to assess the level of immunity against diphtheria and other vaccine preventable diseases in migrant worker population, so that appropriate interventions such as booster vaccination can be implemented proactively to prevent sporadic outbreaks.
| S-EPMC8761332 | biostudies-literature
Project description:IntroductionWorldwide, there are between 50-67 million migrant domestic workers, the majority of whom are women. In many countries, provisions are not in place to protect female migrant domestic workers. These women may be at risk of occupational and social stressors, including exploitation and abuse, which may negatively impact on their quality of life, including psychological health. Research examining the occupational, social, and psychological needs of FMDWs from a public health perspective is critical to guide the development of policies which ensure wellbeing, prevent abuse, and align with international priorities to improve population health. Though there have been a number of high-profile incidents of exploitation and abuse, there has been limited research on the stressors experienced by these communities, their perceived impact, or coping mechanisms.Materials and methodsThematic analysis was used to analyse qualitative free-text written responses collected as part of a cross-sectional survey on the relationship between social and occupational stressors and the health and quality of life of FMDWs in Singapore. Responses correspond to open-ended questions in the qualitative component of the survey examining three domains: causes of stress, coping strategies, and what people can do to help with stress.ResultsResponses from 182 FMDWs were analysed. Key themes were identified around causes of stress (including 'work and agency', 'the pervasiveness of financial need', and 'family and obligation'), coping strategies, and social support. Each theme describes key factors which contribute to the occupational and social stressors experienced and reported by FMDWs.DiscussionThis research highlights the stressors FMDWs in Singapore experience, as well as key coping mechanisms. There is a clear need for policies which facilitate FMDWs' ability to utilise these coping resources, and which protect against coercive or exploitative employment conditions. Strategies are also needed to monitor and evaluate policies intended to protect FMDWs, and to strengthen the implementation of global frameworks targeted at improving workplace conditions and workers' rights.
| S-EPMC6426224 | biostudies-literature
Project description:In the United States, approximately 9% of the measles cases reported from 2012 to 2014 occurred in vaccinated individuals. Laboratory confirmation of measles in vaccinated individuals is challenging since IgM assays can give inconclusive results. Although a positive reverse transcription (RT)-PCR assay result from an appropriately timed specimen can provide confirmation, negative results may not rule out a highly suspicious case. Detection of high-avidity measles IgG in serum samples provides laboratory evidence of a past immunologic response to measles from natural infection or immunization. High concentrations of measles neutralizing antibody have been observed by plaque reduction neutralization (PRN) assays among confirmed measles cases with high-avidity IgG, referred to here as reinfection cases (RICs). In this study, we evaluated the utility of measuring levels of measles neutralizing antibody to distinguish RICs from noncases by receiver operating characteristic curve analysis. Single and paired serum samples with high-avidity measles IgG from suspected measles cases submitted to the CDC for routine surveillance were used for the analysis. The RICs were confirmed by a 4-fold rise in PRN titer or by RT-quantitative PCR (RT-qPCR) assay, while the noncases were negative by both assays. Discrimination accuracy was high with serum samples collected ?3 days after rash onset (area under the curve, 0.953; 95% confidence interval [CI], 0.854 to 0.993). Measles neutralizing antibody concentrations of ?40,000 mIU/ml identified RICs with 90% sensitivity (95% CI, 74 to 98%) and 100% specificity (95% CI, 82 to 100%). Therefore, when serological or RT-qPCR results are unavailable or inconclusive, suspected measles cases with high-avidity measles IgG can be confirmed as RICs by measles neutralizing antibody concentrations of ?40,000 mIU/ml.
| S-EPMC4979181 | biostudies-literature
Project description:Objective: Migrant workers, a marginalized and under-resourced population, are vulnerable to coronavirus disease 2019 (COVID-19) due to limited healthcare access. Moreover, metabolic diseases-such as diabetes mellitus (DM), hypertension, and hyperlipidemia-predispose to severe complications and mortality from COVID-19. We investigate the prevalence and consequences of undiagnosed metabolic illnesses, particularly DM and pre-diabetes, in international migrant workers with COVID-19. Methods: In this retrospective analysis, we analyzed the medical records of international migrant workers with laboratory-confirmed COVID-19 hospitalized at a tertiary hospital in Singapore from April 21 to June 1, 2020. We determined the prevalence of DM and pre-diabetes, and analyzed the risk of developing complications, such as pneumonia and electrolyte abnormalities, based on age and diagnosis of DM, and pre-diabetes. Results: Two hundred and fouty male migrant workers, with mean age of 44.2 years [standard deviation (SD), 8.5years], were included. Twenty one patients (8.8%) were diagnosed with pre-diabetes, and 19 (7.9%) with DM. DM was poorly controlled with a mean HbA1c of 9.9% (SD, 2.4%). 73.7% of the patients with DM and all the patients with pre-diabetes were previously undiagnosed. Pre-diabetes was associated with higher risk of pneumonia [odds ratio (OR), 10.8, 95% confidence interval (CI), 3.65-32.1; P < 0.0001], hyponatremia (OR, 8.83; 95% CI, 1.17-66.6; P = 0.0342), and hypokalemia (OR, 4.58; 95% CI, 1.52-13.82; P = 0.0069). Moreover, patients with DM or pre-diabetes developed COVID-19 infection with lower viral RNA levels. Conclusions: The high prevalence of undiagnosed pre-diabetes among international migrant workers increases their risk of pneumonia and electrolyte abnormalities from COVID-19.
| S-EPMC7686043 | biostudies-literature
Project description:ImportanceSince January 2020, Singapore has implemented comprehensive measures to suppress SARS-CoV-2. Despite this, the country has experienced contrasting epidemics, with limited transmission in the community and explosive outbreaks in migrant worker dormitories.ObjectiveTo estimate SARS-CoV-2 infection incidence among migrant workers and the general population in Singapore.DesignProspective serological cohort studies.SettingTwo cohort studies - in a migrant worker dormitory and in the general population in Singapore.Participants478 residents of a SARS-CoV-2-affected migrant worker dormitory were followed up between May and July 2020, with blood samples collected on recruitment and after 2 and 6 weeks. In addition, 937 community-dwelling adult Singapore residents, for whom pre-pandemic sera were available, were recruited. These individuals also provided a serum sample on recruitment in November/December 2020.ExposureExposure to SARS-CoV-2 in a densely populated migrant worker dormitory and in the general population.Main outcomes and measuresThe main outcome measures were the incidences of SARS-CoV-2 infection in migrant workers and in the general population, as determined by the detection of neutralizing antibodies against SARS-CoV-2, and adjusting for assay sensitivity and specificity using a Bayesian modeling framework.ResultsNo evidence of community SARS-CoV-2 exposure was found in Singapore prior to September 2019. It was estimated that < 2 per 1000 adult residents in the community were infected with SARS-CoV-2 in 2020 (cumulative seroprevalence: 0.16%; 95% CrI: 0.008-0.72%). Comparison with comprehensive national case notification data suggested that around 1 in 4 infections in the general population were associated with symptoms. In contrast, in the migrant worker cohort, almost two-thirds had been infected by July 2020 (cumulative seroprevalence: 63.8%; 95% CrI: 57.9-70.3%); no symptoms were reported in almost all of these infections.Conclusions and relevanceOur findings demonstrate that SARS-CoV-2 suppression is possible with strict and rapid implementation of border restrictions, case isolation, contact tracing, quarantining, and social-distancing measures. However, the risk of large-scale epidemics in densely populated environments requires specific consideration in preparedness planning. Prioritization of these settings in vaccination strategies should minimize the risk of future resurgences and potential spillover of transmission to the wider community.
| S-EPMC8636323 | biostudies-literature
Project description:IntroductionA well-nourished workforce is instrumental in eradicating hunger, alleviating poverty, and spurring economic growth. A fifth of the total workforce in high-income countries are migrant workers. Despite the accessibility of nutritious foods in high-income countries, migrant workers often rely on nutrient-poor diets largely consisting of empty calories, which in turn leads to vitamin and mineral deficiency, also called hidden hunger, and resultant productivity loss. Here, we study the magnitude of hidden hunger in male migrant construction workers in Singapore and investigate the impact of consuming fortified rice for 6 consecutive months on the nutrition and health status of these workers.Methods140 male migrant workers aged 20-51 years of either Bangladeshi or Indian ethnicity from a single dormitory in Singapore volunteered to participate in the study. In total, 133 blood samples were taken at the start of the study and were used to assess vitamin B12, hemoglobin, ferritin, folate, and zinc levels; a sub-sample underwent for homocysteine testing. Anthropometric measurements and vital signs, such as blood pressure, were recorded before and after the intervention.ResultsThe results show that vitamin and mineral deficiency was present, especially folate (59% of workers deficient) and vitamin B12 (7% deficient, 31% marginally deficient). The consumption of fortified rice significantly improved the vitamin, iron and zinc level in the workers and significantly reduced the systolic blood pressure amongst the Bangladeshi migrant workers, specifically.ConclusionOur study demonstrates that fortified rice may have a positive impact on male migrant construction worker health and nutrition status at the workplace.
| S-EPMC10234550 | biostudies-literature
Project description:IntroductionThe health, psychological and socioeconomic vulnerabilities of low-wage migrant workers have been magnified in the COVID-19 pandemic, especially in high-income receiving countries such as Singapore. We aimed to understand migrant worker concerns and coping strategies during the COVID-19 pandemic to address these during the crisis and inform on comprehensive support needed after the crisis.MethodsIn-depth semi-structured interviews were carried out with migrant workers diagnosed with COVID-19. The participants were recruited from a COVID-19 mass quarantine facility in Singapore through a purposive sampling approach. Interviews were transcribed verbatim and thematic analysis performed to derive themes in their collective experience during the crisis.ResultsThree theme categories were derived from 27 interviews: migrant worker concerns during COVID-19, coping during COVID-19 and priorities after COVID-19. Major stressors in the crisis included the inability to continue providing for their families when work is disrupted, their susceptibility to infection in crowded dormitories, the shock of receiving the COVID-19 diagnosis while asymptomatic, as well as the isolating conditions of the quarantine environment. The workers coped by keeping in contact with their families, accessing healthcare, keeping updated with the news and continuing to practise their faith and religion. They looked forward to a return to normalcy after the crisis with keeping healthy and having access to healthcare as new priorities.ConclusionWe identified coping strategies employed by the workers in quarantine, many of which were made possible through the considered design of care and service delivery in mass quarantine facilities in Singapore. These can be adopted in the set-up of other mass quarantine facilities around the world to support the health and mental well-being of those quarantined. Our findings highlight the importance of targeted policy intervention for migrant workers, in areas such as housing and working environments, equitable access to healthcare, and social protection during and after this crisis.
| S-EPMC7985935 | biostudies-literature
Project description:A serosurvey of 600 workers newly arrived in Taiwan from 4 Southeast Asia countries showed that 18 (3%) were positive for Zika virus IgM; 6 (1%) fulfilled the World Health Organization criteria for laboratory-confirmed recent Zika virus infection. The incidence of Zika virus infection in Southeast Asia might be underestimated.
| S-EPMC6433042 | biostudies-literature
Project description:BackgroundThere is a global increase in migrant workers. In Singapore, there are over 230,000 migrant domestic workers (MDWs). Female MDWs may experience high levels of stress and social isolation, which may negatively impact on their health and quality of life. There have also been documented cases of abuse and exploitation. However, there is a lack of empirical research with this population. This study aimed to investigate factors impacting on the health and quality of life of female MDWs in Singapore, including socio-demographic and job related characteristics, stress, social isolation, and working management style.MethodsA cross-sectional survey was carried out with 182 female MDWs in Singapore. The survey examined health and quality of life (WHOQoL-Bréf), social connectedness (the Friendship Scale), and preferred and experienced working management style (the Theory X and Theory Y Questionnaire). Descriptive analyses were carried out in addition to ANOVA, t-tests, and chi-square tests, followed by a multivariate analysis using linear regression.ResultsParticipants were found to have good overall quality of life and satisfaction with health. Age and working experience were found to be significantly (p < 0.05) associated with overall quality of life and three domains (psychological, social, and environmental health). Agreement between experienced and preferred working management style was also found to be associated with higher quality of life scores (with the exception of the social relationships domain). Though women reported relatively good overall quality of life, more than half of participants reported feeling stressed. In addition, nearly 20% of participants reported being isolated or very isolated. Stress was identified to be associated with isolation. In the multivariate analysis, stress was found to contribute to worse quality of life in all domains except social relationships, after adjusting for confounders. Social connectedness was positively associated with all domains of quality of life, and agreement of working management style was positively associated with physical health, psychological health and environmental quality of life.ConclusionsThe findings serve as an evidence-base pointing to the need for policies aimed at decreasing stress and social isolation among female MDWs in order to improve their health and quality of life.
| S-EPMC5634837 | biostudies-literature
Project description:BackgroundHepatitis A virus (HAV) is the predominant cause of acute viral hepatitis worldwide; however, data on HAV antibody prevalence (seroprevalence) among migrant populations are limited. This study aimed to investigate HAV seroprevalence among Qatar's migrant craft and manual workers (CMWs), constituting approximately 60% of the country's population.MethodsHAV antibody testing was conducted on stored serum specimens obtained from CMWs during a nationwide severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) population-based cross-sectional survey between July 26 and September 9, 2020. Associations with HAV infection were investigated through regression analyses.ResultsOf the 2,607 specimens with HAV antibody test results, 2,393 were positive, and 214 were negative. The estimated HAV seroprevalence among CMWs was 92.0% (95% CI: 90.9-93.1%). HAV seroprevalence was generally high but exhibited some variation, ranging from 70.9% (95% CI: 62.4-78.2%) among Sri Lankans to 99.8% (95% CI: 98.2-99.9%) among Pakistanis. The multivariable regression analysis identified age, nationality, and educational attainment as statistically significant factors associated with HAV infection. Relative to CMWs aged ≤29 years, the adjusted relative risk (ARR) was 1.06 (95% CI: 1.03-1.10) in CMWs aged 30-39 years and reached 1.15 (95% CI: 1.10-1.19) in those aged ≥50 years. In comparison to Indians, the ARR was lower among Sri Lankans, assessed at 0.81 (95% CI: 0.72-0.91), but higher among Nepalese at 1.07 (95% CI: 1.04-1.11), Bangladeshis at 1.10 (95% CI: 1.07-1.13), Pakistanis at 1.12 (95% CI: 1.09-1.15), and Egyptians at 1.15 (95% CI: 1.08-1.23). No evidence for differences was found by geographic location or occupation.ConclusionsHAV seroprevalence among Qatar's CMW population is very high, with over nine out of every ten individuals having been exposed to this infection, likely during childhood.
| S-EPMC11232980 | biostudies-literature