Seroprotection rates of vaccine-preventable diseases among newly arrived Eritrean asylum seekers in Switzerland: a cross-sectional study

Measles, mumps, rubella and varicella antibodies among international and domestic university students

BACKGROUND

Vaccine-preventable infections are generally well controlled in Australia. However, gaps in immunity can lead to outbreaks and are important to identify. Young adults are a highly mobile population and a potential source of imported infections. We aimed to evaluate anti- measles, mumps, rubella and varicella (MMR&V) IgG seroprevalence and explore factors relating to antibody seropositivity.

METHODS

A cross-sectional online survey was conducted among students from a large Australian university to collect demographic, vaccination, infection and travel characteristics. Blood samples were collected to measure MMR&V seroprevalence. Logistic regression was used to identify factors associated with seropositivity.

RESULTS

Among 804 university students, seroprevalence (positive or equivocal) for measles was 82.3% (95% CI 79.6-84.8%), mumps 79.5% (95% CI 76.7-82.3%), rubella 91.5% (95% CI 89.6-93.5%) and varicella 86.2% (95% CI 84.1-88.8%), with 452 (56.2%, 95% CI 52.8-59.6) seropositive to all four viruses. Varicella seropositivity was highest in the older birth cohort (born 1988-1991). Measles seropositivity was higher for international students compared to domestic students. Among international students, mumps seroprevalence was significantly lower than measles and rubella seroprevalence. International travel in the previous 12 months was reported by 63.1% of students, but only 18.2% of travellers reported seeking pre-travel health advice prior to most recent international travel.

CONCLUSIONS

Overall, this study suggests immunity to MMR&V is sub-optimal. We found the university student population to be highly mobile and unlikely to seek pre-travel advice; thus, they are a potential source of infection importation. The implementation of university immunization policies could address the gaps identified and our findings can inform the development of targeted vaccination campaigns.

Epidemiology of confirmed measles virus cases, surveillance, incidence, and associated factors in Eritrea: 18-year retrospective analysis

Background

Despite the outstanding measles vaccine coverage (MVC) in Eritrea, sporadic outbreaks are not uncommon. Therefore, understanding the incidence of laboratory-confirmed measles virus cases, related factors, and spatial inequalities in testing and surveillance remains crucial. In this analysis, we evaluated the incidence and spatiotemporal distribution of measles in Eritrea. An evaluation of the factors associated with measles vaccination and IgM positive (+) febrile rash was also undertaken.

Methods

A retrospective (period: 2002-2020) study was carried out by abstracting data from the integrated disease surveillance and response database (IDSR). Data was analyzed using descriptive statistics and binary logistic regression. Spatial variability and distribution of confirmed cases was evaluated using ArcGIS Pro version 3.0.1.

Results

In total, 9,111 suspected cases, 2,767 [1,431 (51.7%) females] were serologically tested. The median (IQR) age, minimum-maximum age were 7 years (IQR: 4-14 years) and 1 month-97 years, respectively. Among the 608(21.9%) laboratory-confirmed cases, 534 (87.8%) were unvaccinated and 53 (9.92%) were < 1 year old. The crude incidence rate for MV was 14/100,000 persons. The age-specific positivity rate per 100,000 suspected cases tested was 21.5 with individuals >30 years presenting with the highest rates (69.9/100,000). Higher odds (OR) of MV test positivity was associated with age at onset - higher in the following age-bands [10-14 years: OR = 1.6 (95%CI, 1.1-2.2, value of p = 0.005); 15-29 years: OR = 7.0 (95%CI, 5.3-9.2, value of p = 0.005); and > =30 years: OR = 16.7 (95%CI, 11.7-24) p < 0.001]. Other associations included: Address - higher in Anseba (OR = 2.3, 95%CI: 1.7-3.1, value of p<0.001); Debub (OR = 2.7, 95%CI: 1.9-3.9, value of p < 0.001); Gash-Barka (OR = 15.4, 95%CI: 10.9-21.7, value of p < 0.001); Northern Red Sea (OR = 11.8, 95%CI: 8.5-16.2, value of p < 0.001); and Southern Red Sea (OR = 14.4, 95%CI: 8.2-25.2, value of p < 0.001). Further, test positivity was higher in health centers (OR = 2.5, 95%CI: 1.9-3.4, value of p < 0.001) and hospitals (OR = 6.8, 95%CI: 5.1-9.1, value of p < 0.001). Additional factors included vaccination status - higher in the unvaccinated (OR = 14.7, 95%CI: 11.4-19.1, value of p < 0.001); and year of onset of rash - (higher >2015: OR = 1.4, 95%CI: 1.1-1.7, value of p<0.001). Uptake of measles vaccine associated with a similar complement of factors.

Conclusion

In large part, efforts to eliminate measles in Eritrea are hindered by disparities in vaccine coverage, under-surveillance, and low vaccination rates in neighboring countries. Enhanced surveillance and regional micro planning targeting hard-to-reach areas can be an effective strategy to improve measles elimination efforts in Eritrea.

Vaccination programs for children aged up to 18 years in Europe, 2020

Although all European countries have vaccination policies for children, there are no comprehensive studies of pediatric vaccination programs in Europe. We studied vaccination programs for children in Europe. Vaccinations against diphtheria, tetanus, pertussis, poliomyelitis, Haemophilus influenzae type b, hepatitis B, measles, mumps, rubella, and influenza existed in 42 countries, against human papilloma virus in 41 countries, and against pneumococcus in 40 countries. In addition, the following vaccinations existed: against tuberculosis (35 countries), hepatitis A (33), meningococcus A, C, W, Y (30), rotavirus and varicella (28 countries each), meningococcus B (24), tick-born encephalitis (22), and meningococcus C (16). Mandatory vaccinations are implemented in 21 countries, mainly against diphtheria, tetanus, pertussis, poliomyelitis, H. influenzae type b, hepatitis B, measles, mumps, rubella, tuberculosis, and pneumococcus. There are significant differences among pediatric vaccination programs in Europe regarding number, schedules, indications, and regulatory frame (recommended or mandatory vaccinations). A consensus-based vaccination program for all children is needed.

Ongoing toxin-positive diphtheria outbreaks in a federal asylum centre in Switzerland, analysis July to September 2022

Two diphtheria outbreaks occurred in a Swiss asylum center from July to October 2022, one is still ongoing. Outbreaks mainly involved minors and included six symptomatic respiratory diphtheria cases requiring antitoxin. Phylogenomic analyses showed evidence of imported and local transmissions of toxigenic strains in respiratory and skin lesion samples. Given the number of cases (n = 20) and the large genetic diversity accumulating in one centre, increased awareness and changes in public health measures are required to prevent and control diphtheria outbreaks.

Access to Vaccination among Disadvantaged, Isolated and Difficult-to-Reach Communities in the WHO European Region: A Systematic Review

Vaccination has a significant impact on morbidity and mortality. High vaccination coverage rates are required to achieve herd protection against vaccine-preventable diseases. However, limited vaccine access and hesitancy among specific communities represent significant obstacles to this goal. This review provides an overview of critical factors associated with vaccination among disadvantaged groups in World Health Organisation European countries. Initial searches yielded 18,109 publications from four databases, and 104 studies from 19 out of 53 countries reporting 22 vaccine-preventable diseases were included. Nine groups representing the populations of interest were identified, and most of the studies focused on asylum seekers, refugees, migrants and deprived communities. Recall of previous vaccinations received was poor, and serology was conducted in some cases to confirm protection for those who received prior vaccinations. Vaccination coverage was lower among study populations compared to the general population or national average. Factors that influenced uptake, which presented differently at different population levels, included health service accessibility, language and vaccine literacy, including risk perception, disease severity and vaccination benefits. Strategies that could be implemented in vaccination policy and programs were also identified. Overall, interventions specific to target communities are vital to improving uptake. More innovative strategies need to be deployed to improve vaccination coverage among disadvantaged groups.

Concordance of self-reported varicella history and serology among adolescent and adult refugee patients at a primary care clinic in Toronto, Canada

BACKGROUND

Previous studies have found higher rates of varicella susceptibility among migrants from tropical regions. This study seeks to estimate the prevalence of varicella susceptibility in a cohort of newly arrived refugees and refugee claimants at a primary care clinic in Toronto and to compare patients' self-reported history of varicella infection with serologic test results.

METHODS

We conducted a retrospective chart review of 1888 refugee patients aged 13 years and older rostered at a specialized primary care clinic in Toronto from December 2011 to October 2017. Basic sociodemographic variables, self-reported varicella history, and varicella serologic results were examined.

RESULTS

Based on serologic testing, 8.5% of individuals were varicella non-immune, with highest rates of varicella susceptibility among adolescents aged 13-19 years (13.5%). All adults over age 60 were varicella immune on serology (n = 56). A positive self-reported history of varicella infection was strongly predictive of varicella immunity on serology (PPV 96.8%; 95% CI: 95.2-97.9). A self-reported history of no prior varicella infection did not correlate reliably with serologic test results (NPV 15.8%; 95% CI: 13.3-18.0). A substantial proportion of patients (34.1%) were unsure of their varicella history.

CONCLUSION

Identification and immunization of varicella susceptible refugee newcomers remains a health care priority. Self-reported history of varicella infection had mixed reliability as a predictor of varicella immunity.

Seroprevalence of vaccine-preventable and non-vaccine-preventable infections in migrants in Spain

BACKGROUND

Updated seroprevalence studies of infections in migrants may aid the design of tailored vaccination and prevention programmes. The objective of this study was to describe the seroprevalence rates for potentially transmissible viral infections in migrants attended at a referral centre in a major European city.

METHODS

Descriptive analysis of seroprevalence of vaccine-preventable and non-vaccine-preventable infections in migrants attended at a centre in Madrid, Spain (2018-19). Recorded variables included age, gender, country of birth/continent of origin, time from arrival to Spain until first clinic visit, rubella, measles, mumps, varicella (VZV), hepatitis B virus (HBV), hepatitis A virus (HAV), hepatitis C virus (HCV) and HIV serology.

RESULTS

In total, 468 patients were included, 135 females (28.8%) and 333 males (71.2%), mean age 30.4 years. The majority of patients were from Africa (52.5%, of which 88.2% from sub-Saharan Africa), followed by Latin America (38.5%) and other areas (9%). Seroprevalence for tested migrants for rubella, measles and mumps was < 95% in the group overall (91% rubella, 88% measles, 83% mumps) and lower rates were observed in migrants >20 years (compared with those ≤ 20 years). Over 10% of females were potentially susceptible (negative/indeterminate serology) to rubella (11.4%), measles (12.7%) or mumps (10.3%). Lowest rates of rubella seropositivity were in Latin American migrants (over 12% potentially susceptible); measles and mumps seropositivity was lowest in migrants from areas other than Africa/Latin America (74% and 68%, respectively). Seroprevalence rates were 91% for VZV, 90% overall for HAV, ~6% for HBV chronic infection (~50% of migrants tested susceptible), 2% for HCV and 6% for HIV.

CONCLUSIONS

Differences in seroprevalence for vaccine-preventable and transmissible infections according to gender, age range and area of origin were observed. Tailored screening, vaccination and prevention strategies in potentially vulnerable migrant groups should be designed.

Utility of the Tétanos Quick Stick® in the vaccine catch-up of adult migrants without proof of prior vaccination

BACKGROUND

Unknowing immunity status make migrants vaccine catch-up difficult. The interest of using a rapid tetanus immunotest as the Tétanos Quick Stick® (TQS®) to assess immunity status against tetanus has been evaluated in emergency rooms and it is now commonly used. The study aim was to evaluate TQS® as a tool for migrants' vaccine catch-up.

METHODS

From December 2018 to February 2019, a prospective study was performed and included consecutively migrants who attented to the primary medicine outconsultation of a health care centre in Paris. Migrants above 18, without any records of tetanus immunization were included and a TQS® was performed during a medical consultation. Adapted vaccine catch-up was then proposed. Immunity against tetanus among migrants, factors associated with positive TQS® and costs savings were evaluated.

RESULTS

TQS® test was positive for 32% of the 310 included patients. In the univariable analysis, factors associated to the presence of a positive TQS® test were a female gender (OR = 1.69 CI95% [1.02-2.80]) and an urban living in the country of origin (OR = 1.79 CI95% [1.07-3.02]). In the multivariable analysis, these factors were not significantly associated to a positive TQS®. Anamnesis was not correlated to the immunity status: only 26% of the migrants who reported vaccinations in childhood, adolescence and adulthood had a positive TQS® test. The use of TQS® test allowed savings of 6,522 US$ as compared to the immediate catch-up strategy for the 310 patients.

CONCLUSION

The TQS® test is an acceptable, simple, rapid and cost saving test that could find a place in the migrants' vaccine catch-up.

Measles Resurgence in Europe: Migrants and Travellers are not the Main Drivers

Measles is a highly transmissible viral infection that may lead to serious illness, lifelong complications, and death. As there is no animal reservoir for measles, measles resurgence is due to human movement of viremic persons. Therefore, some have blamed the enormous migration into Europe in the past 5 years for the measles resurgence in this region. We set out to determine the main driver for measles resurgence in Europe by assessing vaccine coverage rates and economic status in European countries, number of migrants, and travel volumes. Data on measles vaccine coverage rates with two vaccine doses of measles, mumps and rubella (MMR) [Measles Containing Vaccine (MCV)2] and total number of measles cases in 2017 for Europe, including Eastern European countries, were obtained, in addition to Gross Domestic Product (GDP), and number of migrants and tourist arrivals. The outcome measured, incidence of measles per 100,000, was log transformed and subsequently analyzed using multiple linear regression, along with predictor variables: number of international migrants, GDP per capita, tourist arrivals, and vaccine coverage. The final model was interpreted by exponentiating the regression coefficients. Incidence of measles was highest in Romania (46.1/100,000), followed by Ukraine (10.8/100,000) and Greece (8.7/100,000). MCV2 coverage in these countries is less than 84%, with lowest coverage rate (75%) reported in Romania. Only vaccine coverage appears to be the significant predictor in the model (p < 0.001) for incidence of measles even after adjusting for international migrants, international tourist arrivals, and GDP per capita. With one unit increase in vaccination coverage, the incidence of measles decreased by 18% [95% confidence interval (CI): 10–25]. Our results showed that number of migrants and international tourist arrivals into any of the European countries were not the drivers for increased measles cases. Countries with high vaccine coverage rates regardless of economic status did not experience a resurgence of measles, even if the number of migrants or incoming travellers was high. The statistically significant sole driver was vaccine coverage rates. These analyses reemphasize the importance of strategies to improve national measles vaccination to achieve coverage greater than 95%.

Skin diseases in displaced populations: a review of contributing factors, challenges, and approaches to care

There are 70.8 million persons displaced worldwide due to war, persecution, and violence. Eighty percent of displaced persons reside in low- and middle-income countries with limited healthcare resources. Cutaneous diseases are commonly reported among displaced persons owing to numerous interrelated factors such as inadequate housing, overcrowding, food insecurity, environmental exposures, violence including torture, and breakdown of healthcare infrastructure. Diagnosis and management of these conditions, as well as an understanding of the context in which they present, is crucial to providing dermatologic care for displaced populations worldwide. Herein, we define displaced populations and, within this context, review the epidemiology of skin diseases, discuss pertinent skin conditions, examine challenges to care provision, and present approaches for improving dermatologic care. Inflammatory and communicable infectious disorders are the most common skin diseases seen in displaced populations. Other relevant conditions include skin manifestations of heat injuries, cold injuries, immersion foot syndromes, macronutrient and micronutrient deficiencies, torture, and sexual and gender-based violence. Provision of dermatologic care to displaced populations is hampered by limited diagnostic and therapeutic resources and specialist expertise. Medical screening for cutaneous disorders, context-relevant dermatology training, and telemedicine are potential tools to improve diagnosis and management of skin diseases in displaced populations.

Pre-vaccination screening strategies for the use of the CYD-TDV dengue vaccine: A meeting report

The first licensed dengue vaccine, CYD-TDV (Dengvaxia) is efficacious in seropositive individuals, but increases the risk for severe dengue in seronegative persons about two years after administration of the first dose. For countries considering the introduction of Dengvaxia, WHO recommends a pre-vaccination screening strategy whereby only persons with evidence of a past dengue infection would be vaccinated. Policy-makers need to consider the risk-benefit of vaccination strategies based on such screening tests, the optimal age to introduce the vaccine, communication and implementation strategies. To address these questions, the Global Dengue and Aedes-transmitted diseases Consortium (GDAC) organized a 3-day workshop in January 2019 with country representatives from Asia and Latin America. The meeting discussions highlighted many challenges in introducing Dengvaxia, in terms of screening test characteristics, costs of such tests combined with a 3-dose schedule, logistics, achieving high coverage rates, vaccine confidence and communication; more challenges than for any other vaccine introduction programme. A screening test would require a high specificity to minimize individual risk, and at the same time high sensitivity to maximize individual and population benefit. The underlying seroprevalence dependent positive predictive value is the best indicator for an acceptable safety profile of a pre-vaccination screening strategy. The working groups discussed many possible implementation strategies. Addressing the bottlenecks in school-based vaccine introduction for Dengvaxia will also benefit other vaccines such as HPV and booster doses for tetanus and pertussis. Levels of public trust are highly variable and context specific, and understanding of population perceptions and concerns is essential to tailor interventions, monitor and mitigate risks.