Imported infections: What information should be collected by surveillance systems to inform public health policy?

Sex and age as determinants of the seroprevalence of anti-measles IgG among European healthcare workers: A systematic review and meta-analysis

INTRODUCTION

The international literature shows good evidence of a significant rate of measles susceptibility among healthcare workers (HCWs). As such, they are an important public health issue.

METHODS

We conducted a systematic review and meta-analysis to estimate the prevalence of susceptible HCWs in EU/EEA countries and in the UK and to explore the characteristics (sex and age differences) and management of those found to be susceptible.

RESULTS

Nineteen studies were included in the meta-analysis. The prevalence of measles-susceptible HCWs was 13.3% (95 %CI: 10.0-17.0%). In a comparison of serosusceptible female vs. male HCWs, the RR was 0.92 (95 %CI = 0.83-1.03), and in a comparison of age classes (born after vs. before 1980) the RR was 2.78 (95 %CI = 2.20-3.50). The most recent studies proposed the mandatory vaccination of HCWs.

DISCUSSION

According to our meta-analysis, the prevalence of serosusceptible European HCWs is 13%; HCWs born in the post-vaccination era seem to be at higher risk. Healthcare professionals susceptible to measles are a serious epidemiological concern. Greater efforts should therefore be made to identify those who have yet to be vaccinated and actively encourage their vaccination.

Adherence to hepatitis A travel health guidelines: A cross-sectional seroprevalence study in Dutch travelling families - The Dutch travel Vaccination Study (DiVeST)

BACKGROUND

This Dutch travel Vaccination Study (DiVeST) aimed to study adherence or compliance to Dutch travel health guidelines in travelling families and to identify risk groups to provide better advice and protection for international travellers.

METHODS

Between 2016 and 2018, family members who travelled to Eastern Europe or outside Europe during the preceding year were recruited via Dutch secondary schools. The vaccination status of the travellers was assessed using questionnaires and vaccination records and hepatitis A virus antibody concentrations in dried blood spot (DBS) eluates. Subgroups of travellers with lower adherence to guidelines were identified.

RESULTS

Of the 246 travellers that participated in this study, 155 (63%) travelled to destinations for which the HAV vaccination was recommended. Of these 155 travellers, 56 (36%) said they visited a pre-travel clinic, and 64 of them (41%) showed a valid HAV vaccination in their vaccination records. Of the 145 travellers with available DBS eluates, anti-HAV antibodies were detected in 98 (68%) of them.

CONCLUSIONS

We found that adherence to travel health guidelines, in terms of HAV vaccination, was suboptimal. According to our results, specific attention should be paid to children, persons visiting friends and relatives and those who travel relatively short distances.

Travel-associated hepatitis A in Europe, 2009 to 2015

Travel to countries with high or intermediate hepatitis A virus (HAV) endemicity is a risk factor for infection in residents of countries with low HAV endemicity. Aim: The objective of this study was to estimate the risk for hepatitis A among European travellers using surveillance and travel denominator data. Methods: We retrieved hepatitis A surveillance data from 13 European Union (EU)/ European Economic Area (EEA) countries with comprehensive surveillance systems and travel denominator data from the Statistical Office of the European Union. A travel-associated case of hepatitis A was defined as any case reported as imported. Results: From 2009 to 2015, the 13 countries reported 18,839 confirmed cases of hepatitis A, of which 5,233 (27.8%) were travel-associated. Of these, 39.8% were among children younger than 15 years. The overall risk associated with travel abroad decreased over the period at an annual rate of 3.7% (95% confidence interval (CI): 0.7–2.7) from 0.70 cases per million nights in 2009 to 0.51 in 2015. The highest risk was observed in travellers to Africa (2.11 cases per million nights). Cases more likely to be reported as travel-associated were male and of younger age (< 25 years). Conclusion: Travel is still a major risk factor for HAV infection in the EU/EEA, although the risk of infection may have slightly decreased in recent years. Children younger than 15 years accounted for a large proportion of cases and should be prioritised for vaccination.

Hepatitis A surveillance: sensitivity of two information sources

BACKGROUND

The frequency of mild forms of hepatitis A, especially in children, could lead to underreporting. The objective of the study was to investigate the sensitivity of two surveillance systems, mandatory Statutory Disease Reports and the Microbiological Reporting System of Catalonia, using capture-recapture techniques.

METHODS

The study was conducted in Catalonia between 2011 and 2015. Hepatitis A cases reported to two independent surveillance systems were included: Statutory Disease Reports (SDR) and Microbiological Reporting System of Catalonia (MRS). The variables collected were: age, sex, year of declaration, size of municipality (< 10,000 and ≥ 10,000), country of birth (Spain or abroad), reporting centre (primary care/hospital) and notification method (electronic or paper). The capture-recapture analysis and the estimate of 95% confidence intervals were made using the Chapman formula for comparison of two sources, both for the estimate of the total number of cases and the stratification according to variables. Multinomial logistic regression was performed to obtain an adjusted estimate.

RESULTS

The SDR had a greater overall sensitivity than the MRS (48.8%; 43.5-55.6 vs. 19.3%; 17.2-21.9). In cases aged < 15 years the sensitivity of both systems was higher (76.6%; 72.7-81 vs. 25.2%; 20.9-29.5) than in cases aged > 15 years (25.5%; 22.8-28.3 vs. 12.1%; 10-14.2). For those born in Spain, the sensitivity was 57.2% (49.6-67.4) in the SDR and 27.1% (23.5-31.9) in the MRS, lower than that for foreign-born patients (58%; 51.2-66.8 vs. 49.1%; 43.4-56.6). In electronically-reported cases, the sensitivity was much higher in the SDR than in the MRS (47.2%; 42.3-52.1 vs. 9.4%; 6.5-12.3). No differences were observed according to sex, size of municipality, and year of declaration or reporting centre. The estimated total number of cases using the Chapman formula was very similar to the adjusted estimate (1121; 985-1258 vs. 1120; 876-1525), indicating the robustness of the results.

CONCLUSIONS

The sensitivity of the SDR was greater than that of MRS, especially in patients aged < 15 years, although for patients born abroad the difference in sensitivity was lower. Reinforced surveillance combining the SDR and MRS improves the efficiency in the detection of cases.

Two cases of imported hemorrhagic fever with renal syndrome and systematic review of literature

Many factors are involved in the epidemiology of hemorrhagic fever with renal syndrome (HFRS). Imported cases, as well as those by emigrants, have been reported in literature worldwide. Our goal is to document two cases of HFRS, imported by two immigrants from two countries, and to make a review of the imported HFRS literature data. We performed a systematic literature review (PRISMA guidelines) of imported cases of HFRS and herein describe our two clinical cases. We found 20 published papers, with 16 of them in English and 4 in other languages. Twenty-three patients with travel- or immigration-associated HFRS, including our two cases, were identified. We included only papers that were in English. The average age of the patients was 35.9 ± 15.13 years, and the ratio of male to female was 8:1. Imported disease from Europe to Europe occurred in seven cases, America to Europe occurred in four cases, Europe to America occurred in two cases, America to America occurred in two cases, Asia to Asia in one case, Asia to Europe in one case, and Europe to Asia in one case. The results of the two cited cases are based on the clinical-laboratory, anamnestic, and serologic data for both the patients who tested positive for HFRS. Our systematic analysis shows that international travelers are important sources of infectious diseases. HFRS related to travel and immigration is a rare event. Principal risk factors for travelers and immigrants are camping outside recommended areas or under unsuitable conditions. In recent years, various publications have shown that international travelers and immigrants have expanded the spectrum of imported infectious diseases. The literature data show that the actual reported numbers of imported case of HFRS are limited.

The contribution of travellers visiting friends and relatives to notified infectious diseases in Australia: state-based enhanced surveillance

Immigrants and their children who return to their country of origin to visit friends and relatives (VFR) are at increased risk of acquiring infectious diseases compared to other travellers. VFR travel is an important disease control issue, as one quarter of Australia's population are foreign-born and one quarter of departing Australian international travellers are visiting friends and relatives. We conducted a 1-year prospective enhanced surveillance study in New South Wales and Victoria, Australia to determine the contribution of VFR travel to notifiable diseases associated with travel, including typhoid, paratyphoid, measles, hepatitis A, hepatitis E, malaria and chikungunya. Additional data on characteristics of international travel were collected. Recent international travel was reported by 180/222 (81%) enhanced surveillance cases, including all malaria, chikungunya and paratyphoid cases. The majority of cases who acquired infections during travel were immigrant Australians (96, 53%) or their Australian-born children (43, 24%). VFR travel was reported by 117 (65%) travel-associated cases, highest for typhoid (31/32, 97%). Cases of children (aged <18 years) (86%) were more frequently VFR travellers compared to adult travellers (57%, P < 0·001). VFR travel is an important contributor to imported disease in Australia. Communicable disease control strategies targeting these travellers, such as targeted health promotion, are likely to impact importation of these travel-related infections.