Duration of Protection After Vaccination Against Yellow Fever: A Systematic Review and Meta-Analysis.

The duration of protection after a single dose of yellow fever vaccine is a matter of debate. To summarize the current knowledge, we performed a systematic literature review and meta-analysis. Studies on the duration of protection after 1 and ≥2 vaccine doses were reviewed. Data were stratified by time since vaccination. In our meta-analysis, we used random-effects models. We identified 36 studies from 20 countries, comprising more than 17 000 participants aged 6 months to 85 years. Among healthy adults and children, pooled seroprotection rates after single vaccination dose were close to 100% by 3 months and remained high in adults for 5 to 10 years. In children vaccinated before age 2 years, the seroprotection rate was 52% within 5 years after primary vaccination. For immunodeficient persons, data indicate relevant waning. The extent of waning of seroprotection after yellow fever vaccination depends on age and immune status at primary vaccination.

[Travel vaccinations for certain groups of persons]. / Reiseimpfungen für besondere Personengruppen.

The number of international travelers has been continuously increasing in recent decades. Among travelers, there are more and more people at an increased risk for acquiring diseases that could be prevented by vaccines or for the development of a severe course of disease. Risk groups in travel medicine are senior travelers, children, pregnant and breast-feeding women, persons with pre-existing medical conditions, and persons who visit their friends and relatives abroad (VFR). Individuals in these groups require attention during pretravel advice consultations, particularly with regards to recommended vaccinations. On the other hand, for some risk groups, particular vaccines cannot be given for safety reasons or because the response to vaccines is reduced. Not all risk groups or each vaccine have sufficient evidence available, so each patient's risks and benefits must be weighed during pretravel consultation. In this article, the particularities for each risk group with respect to pretravel immunization are highlighted.

Safety and immunogenicity of tetanus/diphtheria vaccination in patients with rheumatic diseases-a prospective multi-centre cohort study.

OBJECTIVES: We aimed to assess the safety and immunogenicity of a diphtheria/tetanus vaccine booster dose in three different patient groups with rheumatic diseases on a variety of immunosuppressive/immunomodulatory medications compared with healthy controls (HCs). METHODS: We conducted a multi-centre prospective cohort study in Switzerland. We enrolled patients with RA, axial SpA/PsA, vasculitis (Behçet's disease, ANCA-associated vasculitis) and HCs. Diphtheria/tetanus vaccination was administered according to the Swiss vaccination recommendations. Blood samples were drawn before vaccination, and 1 month and 3 months afterwards. Antibody concentrations against vaccine antigens were measured by ELISA. Immunogenicity was compared between patient and medication groups. A mixed model was applied for multivariate analysis. Missing data were dealt with using multiple imputation. RESULTS: Between January 2014 and December 2015, we enrolled 284 patients with rheumatic diseases (131 RA, 114 SpA/PsA, 39 vasculitis) and 253 HCs. Of the patients, 89% were on immunosuppressive/immunomodulatory medication. Three months post-vaccination 100% of HCs vs 98% of patients were protected against tetanus and 84% vs 73% against diphtheria. HCs and SpA/PsA patients had significantly higher responses than RA and vasculitis patients. Assessing underlying diseases and medications in a multivariate model, rituximab was the only factor negatively influencing tetanus immunogenicity, whereas only MTX treatment had a negative influence on diphtheria antibody responses. No vaccine-related serious adverse events were recorded. CONCLUSION: Diphtheria/tetanus booster vaccination was safe. Tetanus vaccination was immunogenic; the diphtheria component was less immunogenic. Vaccine responses were blunted by rituximab and MTX. TRIAL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov, Identifier: NCT01947465.

Never seen before? Opisthorchiasis and Clonorchiasis.

Parasitic diseases are relatively rarely diagnosed and treated in Europe. Therefore, European clinicians are not familiar with their clinical and imaging features. In an era of increased human migration, it is fundamental for clinicians to be able to identify such diseases. We have recently described the features of cystic echinococcosis, schistosomiasis, fascioliasis and ascariasis. Here, we report on the clinical and imaging features as well as on the current therapy options of infections by the small liver flukes: Clonorchis sinensis, Opisthorchis viverrini (Southeast Asian liver fluke) and Opisthorchis felineus (cat liver fluke) and other Opisthorchis species prevalent in South Asia.

Accuracy of Diagnostic Tests for Schistosoma mansoni Infection in Asymptomatic Eritrean Refugees: Serology and Point-of-Care Circulating Cathodic Antigen Against Stool Microscopy.

Background: The unprecedented increase in number of African refugees arriving in Europe is confronting clinicians and general practitioners with the question of whether or not and how to screen migrants from endemic regions for Schistosoma mansoni infection. Methods: We assessed the accuracy of 3 different diagnostic tests for S. mansoni infection (stool microscopy [samples prepared by sedimentation technique], serology, and point-of-care circulating cathodic antigen [POC-CCA] urine cassette test) in 107 newly arrived asymptomatic Eritrean refugees in Switzerland. Result: Sixty-three study participants (59%) tested positive by at least 1 of the 3 methods. Thirty-seven participants (35%) were considered to have active schistosomiasis, either due to the detection of parasite eggs in stool and/or the presence of a concordant positive serology and urine POC-CCA test, which we consider to be a suitable surrogate marker of active infection. Of 23 microscopy-positive participants, 22 were positive by serology (95.7% sensitivity) and 21 were positive by the urine POC-CCA test (91.3% sensitivity). The combination of serology and urine POC-CCA testing detected all 23 microscopy-positive study participants (100% sensitivity). Conclusions: With a sensitivity of 100% (95% confidence interval, 82.2%-100%), the combination of serology plus urine POC-CCA testing appears to be the most sensitive screening option for asymptomatic S. mansoni infection in Eritrean refugees, compared with stool sedimentation microscopy.

Steatotic liver disease among lean and non-lean individuals in Southern Lao PDR: a cross-sectional study of risk factors.

BACKGROUND: Steatotic liver disease (SLD) prevalence is rising worldwide, linked to insulin resistance and obesity. SLD prevalence can surpass 10% even among those with normal weight. In Lao People's Democratic Republic (Lao PDR), where Opisthorchis viverrini (OV) trematode infection and type 2 diabetes mellitus (T2DM) are common, infection related liver morbidity such as cholangiocarcinoma (CCA) is high, but data on SLD prevalence is lacking. The objective of this study was to estimate the prevalence and explore determinants of SLD in rural southern Lao PDR for lean and non-lean populations. METHOD: A cross-sectional community-based study assessed SLD prevalence using abdominal ultrasonography (US). Factors investigated for association with SLD were identified by interview, serological tests (Hepatitis B surface antigen (HBsAg); lipids and HbA1c), anthropometrical measurements, and parasitological assessments (OV infection). Uni- and multivariable logistic regression analyses with SLD as endpoint were conducted separately for lean (body mass index (BMI) <23.0 kg/m2) and non-lean (BMI ≥ 23.0 kg/m2) participants. RESULT: 2,826 participants were included. SLD prevalence was 27.1% (95% confidence interval (95% CI) 24.0%-30.4%), higher among non-lean (39.8%) than lean individuals (17.4%). Lean individuals with OV infection had a statistically significant association with lower odds of SLD (adjusted odds ratio (aOR) 0.49, 95% CI 0.33 - 0.73). T2DM showed a significant positive association with SLD in both lean (aOR 3.58, 95% CI 2.28 - 5.63) and non-lean individuals (aOR 3.31, 95% CI 2.31 - 4.74) while dyslipidemia was significantly associated only in the non-lean group (aOR 1.83, 95% CI 1.09 - 3.07). Females participants exhibited elevated odds of SLD in both lean (aOR 1.43, 95% CI 1.02 - 2.01) and non-lean SLD (aOR 1.50, 95% CI 1.12 - 2.01). CONCLUSION: SLD prevalence is notably high among Laotian adults in rural areas, particularly in females and in non-lean individuals. Lean individuals with OV infection exhibited lower SLD prevalence. SLD was more prevalent in individuals with T2DM, independent of BMI. SLD adds to the burden of infection-related liver morbidity in Lao PDR.

Norovirus acute gastroenteritis among US and European travellers to areas of moderate to high risk of travellers' diarrhoea: a prospective cohort study.

BACKGROUND: Acute gastroenteritis (AGE) is a major medical condition for travellers worldwide, particularly travellers to low- and middle-income countries. Norovirus (NoV) is the most common cause of viral AGE in older children and adults, but data on prevalence and impact among travellers is limited. METHODS: Prospective, multi-site, observational cohort study conducted 2015-2017, among adult international travellers from the US and Europe to areas of moderate to high risk of travel-acquired AGE. Participants provided self-collected pre-travel stool samples and self-reported AGE symptoms while travelling. Post-travel stool samples were requested from symptomatic subjects and a sample of asymptomatic travellers within 14days of return. Samples were tested for NoV by RT-qPCR, genotyped if positive, and tested for other common enteric pathogens by Luminex xTAG GPP. RESULTS: Of the 1109 participants included, 437 (39.4%) developed AGE symptoms resulting in an overall AGE incidence of 24.7 per 100 person-weeks (95% CI: 22.4; 27.1). Twenty NoV-positive AGE cases (5.2% of those tested) were identified at an incidence of 1.1 per 100 person-weeks (95% CI: 0.7; 1.7). NoV-positive samples belonged mostly to genogroup GII (18, 85.7%); None of the 13 samples sequenced belonged to genotype GII.4. Clinical severity of AGE was higher for NoV-positive than for NoV-negative cases (mean modified Vesikari Score 6.8 vs 4.9) with more cases classified as severe or moderate (25% vs 6.8%). Eighty percent of NoV-positive participants (vs. 38.9% in NoV-negative) reported at least moderate impact on travel plans. CONCLUSIONS: AGE is a prevalent disease among travellers with a small proportion associated with NoV. Post-travel stool sample collection timing might have influenced the low number of NoV cases detected; however, NoV infections resulted in high clinical severity and impact on travel plans. These results may contribute to targeted vaccine development and the design of future studies on NoV epidemiology.

Challenges to the Fight against Rabies-The Landscape of Policy and Prevention Strategies in Africa.

Nearly 59,000 human deaths worldwide are attributable to rabies annually, of which more than a third occur in Africa. In recent years, progress has been made in both action and collaboration including implementation of surveillance and prevention measures. In this review we assess the scale of surveillance, preventive, and control efforts of canine-transmitted human rabies in African countries. We reviewed literature published from 2014 to 2018, retrieved from electronic databases including MEDLINE, Global Index Medicus, BIOSIS, Science Citation Index, and EMBASE. WHO reports, national disease control program reports, and conference proceedings were also reviewed. The database search was conducted using keywords including rabies, control, and prevention. In forty countries (40/54), some level of rabies control and prevention strategy was available while in fourteen (14/54) countries, no specific national control and prevention strategy for human rabies could be retrieved. Thirty-four (34/54) countries utilized the Stepwise Approach towards Rabies Elimination (SARE) tool to monitor the national rabies control efforts-five of these countries were at the lowest tier (0/5) of the SARE scoring system while no country had achieved the highest score (5/5). High burden countries need to step up the implementation of context specific national rabies control, prevention, and monitoring strategies. As a zoonosis, rabies control and elimination require coordination between human and veterinarian health sectors under the "One Health" umbrella and with national master plans on the prevention and control of neglected tropical diseases ending in 2020, the time to act is now.

Vaccination against Japanese encephalitis with IC51: systematic review on immunogenicity, duration of protection and safety.

Japanese encephalitis is a disease caused by a flavivirus which is transmitted by mosquitos in endemic countries. Considering the potentially severe outcomes of the disease, vaccination is recommended for those at risk of exposure. During recent years, IC51 (IXIARO®, JESPECT®, JEVAL®) has increasingly been used to protect travellers from Europe and the USA. However, no systematic review exists that summarizes the currently available evidence on the immunogenicity and safety of this vaccine. We conducted a systematic review on the immunogenicity and safety of IC51, using the databases PubMed, MEDLINE, EMBASE and ClinicalTrials.gov (search date: 31 August 2019). Data extracted from included studies were grouped by outcomes and stratified by population and setting. Risk of bias (ROB) was assessed using the RoB 2 tool for randomized controlled trials (RCTs) and ROBINS-I for non-randomized studies. Due to high heterogeneity, meta-analysis was not performed. A total of 32 studies from 16 countries met the inclusion criteria (15 RCTs, 17 non-randomized studies). ROB was serious or high in the majority of studies. Seroprotection rates ranged from 93 to 100% in adults (seven studies) and from 91 to 100% in children (four studies). In the study involving adults aged 64 years and older, seroprotection was 65% with higher rates in persons who were previously vaccinated against tick-borne encephalitis virus. Safety was investigated in 27 studies. Rates of serious adverse events were below 5% in all age groups, with the majority not being causally related to the vaccine. IC51 is a safe vaccine with good seroprotective abilities in persons aged >2 months to <64 years. The body of evidence, however, is weakened by a large amount of heterogeneity in study and clinical trial methodology. Further well-designed RCTs with special risk groups are needed.

Morbidity associated with Schistosoma mekongi and concurrent helminth infection in Lao People's Democratic Republic.

In 2006, some 7 years after the halt of a multi-year schistosomiasis control programme, a study was conducted in the southern part of Lao People's Democratic Republic to determine the morbidity associated with Schistosoma mekongi and concurrent helminth infection. In two S. mekongi-endemic districts, Khong and Mounlapamok, 640 individuals aged 9-40 years were randomly selected. Two stool samples were obtained from each participant and subjected to the Kato-Katz technique for helminth diagnosis. Morbidity was assessed by clinical examination and abdominal ultrasonography. Multiple logistic regression analysis was employed to relate S. mekongi infection with morbidity indicators. In Khong district, S. mekongi prevalence was 13-fold higher than in Mounlapamok district (57.7% vs. 4.4%, p < 0.001). Likewise, we observed significantly more often palpated hepatomegaly (15.5% vs. 5.4%) and splenomegaly (9.6% vs. 0.4%). Abdominal ultrasonography revealed that, in Khong district, liver and spleen morbidity occurred more frequently (e.g., enlarged left liver lobe: 89.2% vs. 68.7%, p < 0.001). Single species infection with S. mekongi was associated with enlarged peri-portal vein (adjusted odds ratio (aOR) 47.7, 95% confidence interval (CI) 4.2-85.7, p = 0.002), as was S. mekongi-Opisthorchis viverrini co-infection (aOR 2.2, 95% CI 1.1-4.5, p = 0.020). In conclusion, our study shows that in 2006, several years after the halt of the Lao schistosomiasis control programme that emphasised preventive chemotherapy, S. mekongi infection again had reached high prevalence rates. Infection with S. mekongi was associated with substantial hepatosplenic morbidity. Schistosomiasis control measures were re-instigated in 2010. In view of the ultimate goal to eliminate schistosomiasis, rigorous surveillance and public health responses tailored to the social-ecological settings and long-term programme commitment are warranted.

Point-of-Care Ultrasound in the Diagnosis of Melioidosis in Laos.

Melioidosis is endemic in many rural areas in Southeast Asia where facilities for culture and identification of Burkholderia pseudomallei are often limited. We performed a prospective observational study in patients presenting with fever to Mahosot Hospital, the primary referral hospital in Laos, to establish whether the detection of abscesses on ultrasound could support a presumptive diagnosis of melioidosis. All patients underwent ultrasound examination to detect abscesses in the liver, spleen, prostate, or, if indicated, subcutaneous tissue. We enrolled 153 patients, including 18 patients with melioidosis. Of these, 11 (61%) had an abscess at one or more sites, including five (28%) with splenic and/or liver abscesses. Absence of abscesses cannot rule out melioidosis, but the positive predictive value of abscesses for melioidosis was high at 93% (88-96%). Therefore, in endemic areas, the presence of abscesses in febrile patients should prompt empiric antibiotic therapy for melioidosis even in the absence of culture confirmation.

Performance of the point-of-care circulating cathodic antigen (POC-CCA) urine cassette test for follow-up after treatment of S. mansoni infection in Eritrean refugees.

BACKGROUND: Point-of-care circulating cathodic antigen (POC-CCA) urine cassette testing has become a popular approach to screen for Schistosoma infection. Since the test is also increasingly used for following-up of treatment success, we assessed the assay's diagnostic accuracy after praziquantel treatment of S. mansoni infection among Eritrean refugees in Switzerland. METHODS: In our preceding study, 107 asymptomatic Eritrean refugees in Switzerland were screened for schistosomiasis by stool microscopy, serology, and POC-CCA urine testing. Individuals screened positive by any method were treated with praziquantel and invited for a follow-up visit, repeating the same diagnostic procedures one year after treatment. The POC-CCA baseline and follow-up results were analyzed against the 'baseline microscopy positive cases' (= the most reliably true positive cases) and the 'baseline microscopy plus serology negative cases at baseline and follow-up' (= the most reliably true negative cases). RESULTS: Complete diagnostic baseline and follow-up sampling was available from 48 participants. Compared to most reliably true positive cases at baseline, POC-CCA testing had a sensitivity of 90%. Compared to most reliably true negative cases, POC-CCA testing had a specificity of 73.9%. CONCLUSION: We conclude that the POC-CCA urine test is valuable for screening but its use is not suitable for routine follow-up after treatment.

Review of Dancing Parasites in Lymphatic Filariasis.

Lymphatic filariasis is an infection transmitted by blood-sucking mosquitoes with filarial nematodes of the species Wuchereria bancrofti, Brugia malayi und B. timori . It is prevalent in tropical countries throughout the world, with more than 60 million people infected and more than 1 billion living in areas with the risk of transmission. Worm larvae with a length of less than 1 mm are transmitted by mosquitoes, develop in human lymphatic tissue to adult worms with a length of 7-10 cm, live in the human body for up to 10 years and produce millions of microfilariae, which can be transmitted further by mosquitoes. The adult worms can be easily observed by ultrasonography because of their size and fast movements (the so-called "filarial dance sign"), which can be differentiated from other movements (e. g., blood in venous vessels) by their characteristic movement profile in pulsed-wave Doppler mode. Therapeutic options include (combinations of) ivermectin, albendazole, diethylcarbamazine and doxycycline. The latter depletes endosymbiotic Wolbachia bacteria from the worms and thus sterilizes and later kills the adult worms (macrofilaricidal or adulticidal effect).

Spectrum of infectious diseases among newly arrived Eritrean refugees in Switzerland: a cross-sectional study.

OBJECTIVES: Our study aimed at determining the prevalence of selected infectious diseases among recently arrived Eritrean refugees in Switzerland. METHODS: In this cross-sectional study, asymptomatic Eritrean migrants aged ≥16 years who arrived <24 months ago were recruited at refugee centres in Switzerland. Infectious disease screening included serology for HIV, hepatitis B and C, syphilis and schistosomiasis, polymerase chain reaction (PCR) for malaria, stool microscopy for helminths and intestinal protozoa and circulating cathodic antigen (CCA) testing in urine for schistosomiasis. RESULTS: Among 107 participating Eritrean refugees, point-of-care CCA urine test for Schistosoma mansoni was positive in 43 patients (40.2%; 95% CI 31.9-49.5). Stool microscopy detected eggs of S. mansoni in 23 (21.5%; 95% CI 13.7-29.3), Hymenolepis nana in 11 (10.3%; 95% CI 4.5-16.0), and cysts of Giardia intestinalis in 7 participants (6.5%: 95% CI 1.9-11.2). Two tested positive for hepatitis B (1.9%; 95% CI 0.0-4.4) and one for syphilis (0.9%; 95% CI 0.0-2.8), none tested positive for HIV or hepatitis C. Malaria PCR was positive in six participants (5.6%; 95% CI: 1.2-9.9). CONCLUSIONS: Given the high prevalence of S. mansoni infection and potentially severe long-term sequelae of untreated schistosomiasis, routine screening for schistosomiasis in refugees from Schistosoma-endemic regions should be recommended.

Previous exposure in a high-risk area for travellers' diarrhoea within the past year is associated with a significant protective effect for travellers' diarrhoea: a prospective observational cohort study in travellers to South Asia.

BACKGROUND: Travellers' diarrhoea is the most common health problem in travellers. Depending on the region visited, up to 40% of travellers develop diarrhoea during a 2-week trip. The aim of this study was to assess risk factors for TD among travellers to the Indian subcontinent. METHODS: An observational prospective multicentre cohort study investigated travellers to the Indian subcontinent. Participants completed questionnaires assessing the incidence of travellers' diarrhoea and identifying potential risk factors. Covariates were assessed univariately, followed by a multivariate regression. RESULTS: Two-hundred and twenty-six travellers were enrolled into the study, 178 filled in both pre- and post-travel questionnaires. Overall, the attack rate of travellers' diarrhoea was 38.2%. Travel destination is a key risk factor for the occurrence of TD. Travelling to India or Nepal vs Bhutan is associated with an increased risk for TD (OR 6.68 and 6.62, respectively). A length of stay of more than 3 weeks compared to less than 2 weeks is also associated with a significantly increased risk (OR 5.45). Having stayed in a high-risk area for travellers' diarrhoea within the past year before the current trip is associated with a significantly decreased risk (OR 0.19). No association was found between consumption of high risk food (i.e. tap water, ice cream, raw meat and hamburgers) and travellers' diarrhoea. CONCLUSION: Travellers' diarrhoea is a frequent problem in travellers to the Indian subcontinent. Previous exposure in a high-risk area for travellers' diarrhoea within the past year appears to have a significant protective effect. Furthermore, an association between the occurrence of travellers' diarrhoea and travel destination and length of stay, respectively, was observed. Consumption of risk food did not confer a TD risk in our study.

Serum 25-hydroxyvitamin D levels and intramuscular vitamin D3 supplementation among Eritrean migrants recently arrived in Switzerland.

In a cross-sectional screening programme, we assessed serum vitamin D levels in adult Eritrean refugees recently arrived in Switzerland. Median vitamin D level among 107 participants (95 males and 12 females) was 27 nmol/l (interquartile range 23-42 nmol/l), 86% had insufficient vitamin D levels (≤50 nmol/l) and 36% severe deficiency (<25 nmol/l). In 29 participants who received single-dose intramuscular vitamin D substitution (300 000 IU), median vitamin D levels increased from 25 to 35 nmol/l after 3 months (p = 0.005); only 11 (38%) reached sufficient vitamin D levels. Eritrean migrants should be routinely screened for vitamin D deficiency. Single-dose intramuscular supplementation appeared to be insufficient to achieve optimal levels in the majority of participants.