West Nile Virus Emergence in Germany 2019: Looking for Hidden Human West Nile Virus Infections.

Background: Autochthonous human West Nile virus (WNV) infections were notified in the infectious disease surveillance system in Germany in 2018 for the first time and every year since then. Since clinically apparent infections are infrequent, we conducted two studies to investigate subclinical infections of this emerging disease in Germany in 2019 to detect infections not visible to surveillance based on symptomatic infections: limited-scope blood donor testing and a serosurvey among employees at two Berlin zoos with a history of demonstrated WNV infections in animals. Methods: For the zoo study, employees of the two zoos in Berlin were invited to participate in the study in late 2019. Blood samples were drawn and tested for the presence of antibodies (immunoglobulin M [IgM] and immunoglobulin G [IgG]) against WNV, and two other flaviviruses present in Germany: Usutu virus and Tick-borne encephalitis virus (TBEV). For the study in blood donors, four blood establishments with collection sites in regions with documented WNV-infected animals in 2018 and 2019 participated in the study. All donations in these regions were tested for WNV genome from July to November 2019. Results: In the enzyme-linked immunosorbent assay, none of the 70 tested zoo employees were WNV IgM-positive, 8 were WNV IgG-positive, additional 2 participants had equivocal results. All 10 were negative in the virus neutralization test (VNT) for WNV, but positive in the VNT for TBEV. None of the 4273 samples from blood donors tested in areas with WNV-infected animals was positive for WNV-RNA. Conclusion: Our results indicate that WNV circulation in Germany, though clearly documented in animals in 2019, apparently affected very few humans. Still areas with WNV-positive animals remain risk areas for human infection as well.

Compliance of blood donors in Germany with non-sexual deferral criteria.

BACKGROUND AND OBJECTIVES: In addition to mandatory testing of blood donations, the deferral of donors in the case of various sexual and non-sexual risk exposures ensures the safety of blood products in Germany. The study aimed to quantify non-disclosure of non-sexual risk exposures, as no data are available so far. MATERIALS AND METHODS: We conducted an anonymous online survey among whole-blood donors with successful donations between January and March 2020. Data on travel to countries with endemic malaria, recent mild or febrile infections, tattoos or piercings and drug use were collected. We analysed non-compliance in relation to donor demographics by multivariable analyses. RESULTS: Altogether, 5.4% of the donors were non-compliant. Non-disclosure was highest for mild infection with 3.3% of donors, followed by febrile infections (1.4%), travel to malaria endemic countries (0.7%) and body modifications (0.5%). Intravenous drug use was negligible in our study population. Age was a predictor for all investigated risks, with higher prevalence in younger age groups. Prevalence ratios for non-disclosure of body modifications and mild infection were higher in females than males. Donation in blood establishments with mobile services was associated with higher non-disclosure of mild infections. CONCLUSION: The considerable degree of non-compliance in some donor groups reflects the prevalence of risk factors in the underlying population (e.g., body modification) as well as probable tendency to socially desirable responding. Donor education should not focus exclusively on sexual risk behaviour, as undisclosed non-sexual exposures may bear risks for recipients and donors.

Monitoring the SARS-CoV-2 Pandemic: Prevalence of Antibodies in a Large, Repetitive Cross-Sectional Study of Blood Donors in Germany-Results from the SeBluCo Study 2020-2022.

SARS-CoV-2 serosurveillance is important to adapt infection control measures and estimate the degree of underreporting. Blood donor samples can be used as a proxy for the healthy adult population. In a repeated cross-sectional study from April 2020 to April 2021, September 2021, and April/May 2022, 13 blood establishments collected 134,510 anonymised specimens from blood donors in 28 study regions across Germany. These were tested for antibodies against the SARS-CoV-2 spike protein and nucleocapsid, including neutralising capacity. Seroprevalence was adjusted for test performance and sampling and weighted for demographic differences between the sample and the general population. Seroprevalence estimates were compared to notified COVID-19 cases. The overall adjusted SARS-CoV-2 seroprevalence remained below 2% until December 2020 and increased to 18.1% in April 2021, 89.4% in September 2021, and to 100% in April/May 2022. Neutralising capacity was found in 74% of all positive specimens until April 2021 and in 98% in April/May 2022. Our serosurveillance allowed for repeated estimations of underreporting from the early stage of the pandemic onwards. Underreporting ranged between factors 5.1 and 1.1 in the first two waves of the pandemic and remained well below 2 afterwards, indicating an adequate test strategy and notification system in Germany.

West Nile Virus in Germany: An Emerging Infection and Its Relevance for Transfusion Safety.

West Nile virus (WNV) is an arthropod-borne virus (arbovirus). It circulates in an enzootic cycle between ornithophilic mosquitoes as vectors and reservoirs and avian host species for amplification, but humans can be infected as accidental hosts. In most individuals, WNV infection remains silent, while 20% develop mild symptoms of West Nile fever, and only 1% develop neuroinvasive disease (WNND). Human WNV cases have been identified in Southern and Eastern Europe for more than 20 years, but until 2018, Germany was considered to be a non-endemic country. This changed when in the exceptionally warm summer of 2018, conditions for viral replication in mosquitoes were ideal, and the first WNV cases among birds and horses were identified. The widespread domestic Culex mosquitoes are efficient vectors for WNV. Autochthonous mosquito-borne WNV infections in humans were reported in all following years, indicating a continuous circulation in the affected areas of Central-East Germany. So far, no clear expansion of the affected areas is discernible but may develop. WNV is a transfusion-transmissible-infection, and donor deferral or testing of donations after a stay in an affected area are effective means to ensure transfusion safety. WNV transmissions via blood products often result in WNND due to the predisposing underlying medical conditions of transfusion recipients. From 2020 onwards, roughly 80% of all blood establishments in Germany tested their donations for WNV using nucleic acid amplification techniques in the transmission season. Altogether, 19 confirmed WNV infections were identified from 2020-2021. As long as effective and affordable pathogen reduction is not available for all blood components, WNV testing or donor deferral will be essential. In order to timely identify affected areas, combined results of human and veterinary surveillance are needed. Partnerships between public health experts, transfusion medicine specialists, veterinarians, and entomologists should be strengthened to ensure a One Health approach.

[Epidemiology of viral hepatitis A to E in Germany]. / Epidemiologie der Virushepatitiden A bis E in Deutschland.

Viral hepatitis A to E describes various infectious inflammations of the liver parenchyma that are caused by the hepatitis viruses A to E (HAV, HBV, HCV, HDV, and HEV). Although the clinical pictures are similar, the pathogens belong to different virus families and differ in terms of pathogenesis, transmission routes, clinical course, prevention, and therapy options. In Germany, there is mandatory reporting according to the Infection Protection Act (IfSG) for direct or indirect laboratory evidence and for suspicion, illness, and death of viral hepatitis. The data are transmitted to the Robert Koch Institute.In this article, on the basis of published studies and notification data, we describe the epidemiology of hepatitis A to E as well as current challenges and prevention approaches. In particular, the latter contains the improvement of existing vaccination recommendations (hepatitis A and B); improvement of access to prevention, testing, and care including therapy with antiviral drugs (hepatitis B, C, and D) and the detection and prevention of foodborne infections and outbreaks; and improvements in the field of food safety (hepatitis A and E).

Undisclosed Sexual Risk Exposures: Results of a Nationwide Compliance Study among Whole Blood Donors in Germany.

Background: Undisclosed sexual infection risks are the main reasons for transfusion transmissible infections in German blood donors that have qualified for donation by donor health interviews and questionnaires. Until now, data about compliance with deferral criteria were only available from post-donation interviews with infected donors, and information about the proportion of donors which did not disclose (sexual) risks at the donor health questionnaire was not available. Methods: A prospective nationwide anonymous online survey was conducted to investigate compliance of whole blood donors with deferral criteria for sexual infection risks. Twenty-one blood establishments which represent 80% of the regular whole blood-donor population invited all donors which donated blood during an 8-week period between January and March 2020. Results: 14,882 participants completed the questionnaire. A relevant proportion of non-compliance was shown (3.0%, 95% CI: 2.7-3.3%) - with male donors being non-compliant significantly more frequently than females (3.5% vs. 2.2%, p < 0.001). A quarter of the non-compliant men were MSM (0.9%, 95% CI: 0.7-1.1%). Non-compliance was strongly associated with the perception that questions about sexual risk exposures are too private. This is in line with the finding that a large proportion of donors (21%) refused to answer at least one question about sexual infection risks. Conclusion: The presented data, collected for the first time, is suitable for assessing the impact of changes in the donor selection process. Donor's limited willingness to provide detailed information about sexual risk behaviour has to be kept in mind when further strategies for fair appraisal of individual sexual infection risks will be discussed.

German and international studies on SARS-CoV-2 seroprevalence.

Since the beginning of the year 2020, the SARS-CoV-2 coronavirus has spread globally at a tremendous pace. Studies on the prevalence of SARS-CoV-2 antibodies in the population help estimate the number of people that have already been infected. They also allow an estimate of the number of undetected infections i.e. infections that do not appear in data on officially reported cases. The interpretation of study results needs to consider bias from selective sampling and the diagnostic test properties. To promote networking and co-operation between scientists, the Robert Koch Institute has compiled an overview of the seroepidemiological studies conducted in Germany on its website, which is regularly updated. The RKI conducts searches, for example of press releases, study registry entries or preprint server publications, and contacts the lead investigators of these studies. Of the 40 studies contacted so far, 24 have already provided information (as of 25.06.2020). We can differentiate between studies of the general population, of selected population groups such as healthcare workers, or of ongoing cohorts. This article provides an overview of such studies from Germany, but also of selected international studies. A special focus is set on studies of children and adolescents, which are now of particular interest due to the planned reopening of childcare facilities and schools.

Low prevalence of Borna disease virus 1 (BoDV-1) IgG antibodies in humans from areas endemic for animal Borna disease of Southern Germany.

Borna disease virus-1 (BoDV-1) was recently discovered as cause of severe and often fatal encephalitis in humans. BoDV-1 is known to cause neurological disease in horses and sheep mainly in South and Central Germany. The virus is maintained in bicolored white-toothed shrews (Crocidura leucodon). The incidence of infection and risk factors in humans are completely unresolved. Veterinarians may be disproportionally BoDV-1-exposed through contact to animals not recognized to be BoDV-1 infected. We conducted three serosurveys predominantly in endemic areas of South Germany for the presence of BoDV-1-reactive antibodies. Anonymized residual samples from two serosurveys of veterinarians (n = 736) with interview data on exposures and one serosurvey among blood donors (n = 373) were screened with an indirect immunofluorescence antibody test, followed by a newly developed immunoblot as confirmatory assay. One serum from a 55-59-year-old veterinarian who worked in an animal practice and as a meat inspector but none from blood donors tested positive by the screening and confirmatory assays. We show that seropositive individuals are rare even in areas with highest zoonotic risk and in a group with potentially elevated exposure risk. In light of the low seroprevalence demonstrated here, the high case-fatality rate in clinically observed human BoDV-1 infections is even more impressive.

Anti-HBc screening - is it worth the effort? Results of a 10-year surveillance programme covering more than 30 million donations in Germany.

BACKGROUND AND OBJECTIVES: Antibodies to hepatitis B core antigen (anti-HBc) testing were added to hepatitis surface antigen (HBsAg) screening in Germany in 2006 to prevent hepatitis B virus (HBV) transmissions by chronically infected donors. We report the results of a national surveillance of anti-HBc-reactive and HBsAg-negative donations and assess the resulting gain in blood safety and the donor loss. MATERIALS AND METHODS: Donations were tested for anti-HBc, and if reactive, by sensitive individual donation nucleic acid testing (ID-NAT) and for antibodies to HBsAg (anti-HBs). Data from the national anti-HBc surveillance from 2006 to 2015 determined the proportion of anti-HBc-reactive donations stratified for donor type, sex, anti-HBs concentration and NAT-positivity. Donor loss due to anti-HBc-reactive results was quantified. RESULTS: Of 31 562 556 donations screened, 70 671 were anti-HBc reactive but HBsAg negative (0.22%). The proportion of repeat donors with these test results decreased significantly from 0.25% in 2007 to 0.08% in 2015. In the entire study period, 82 HBV-NAT-positive donations were identified. Of these, 47 donations were only identified by ID-NAT. A total of 54 203 anti-HBc-reactive units were discarded either due to possible infectiousness (NAT positive or anti-HBs concentration <100 IU/l) or because no further testing was performed. CONCLUSION: Anti-HBc screening has improved blood safety in Germany. HBV-NAT-positive donations were identified after ID-NAT was triggered by the initial reactive anti-HBc result. The observed loss of donations was sustainable for maintaining an adequate blood supply in Germany.

Which Infectious Blood Donors Could Be Identified by the Donor History Questionnaire? - Comparison of Blood Donors Infected with HIV or HCV with Notified Cases from General Population in Germany.

BACKGROUND: Potential risks for transfusion-transmissible infections are identified by donor history questionnaires (DHQs), and donors with higher risks are deferred from donation. We assessed to which extent the currently used DHQs support the identification of infections among blood donors. METHODS: Between 2006 and 2013, we analyzed data from notified HIV and HCV cases in the general population and positive blood donors in Germany. Logistic regressions were used to identify relevant infection risks. We estimated the possible effect of improved capture of risk factors for donor selection by calculation of population attributable fractions (PAF). RESULTS: Risky sexual contacts - MSM as well as heterosexual contacts - were the most prominent infection risks among HIV-infected donors. Whereas MSM contacts were significantly less reported by donors than by cases from the general population, 58% of donors disclosed heterosexual risks compared to 26% of notified cases. The complete identification of heterosexual risk contacts might prevent acceptance of 53% of HIV-infected donors. HCV-infected donors were more likely to report heterosexual exposure, imprisonment, and piercing/tattoo than notified HCV cases. Improved recording of piercing/tattoo could prevent acceptance of 16% of HCV-infected donors. CONCLUSION: Donor selection should be improved with special attention to the identification of (hetero)sexual risk factors, invasive procedures (piercing/tattoo and imprisonment) applying well-designed DHQs, effective donor education, and confidential environment in all steps of the selection process.

Blood donor deferral policies across Europe and characteristics of men whohave sex with men screened for human immunodeficiency virus in bloodestablishments: data from the European Men-who-have-sex-with-men Internet Survey (EMIS).

BACKGROUND: The predominant mode of transmission of human immunodeficiency virus (HIV) in Europe is male-to-male transmission. Men who have sex with men (MSM) are deferred from donating blood in many countries, but nevertheless do donate blood. Based on data from 34 countries, we estimated the proportion of MSM screened for HIV in the context of a blood donation and identified individual factors associated with this HIV screening in order to propose possible public health interventions. MATERIALS AND METHODS: In 2010, the first European MSM Internet Survey (EMIS) collected self-reported data on HIV testing from >180,000 MSM in 38 European countries. Using logistic regression, demographic and behavioural factors associated with screening for HIV in blood establishments were identified. Stratified by European sub-region, we analysed the proportion of MSM screening in blood establishments by time elapsed since last negative HIV test. RESULTS: Donor eligibility criteria for MSM vary across Europe with most countries using permanent deferral. The Western region had the lowest (2%) proportion of MSM screened in blood establishments and the Northeastern region had the highest (14%). Being <25 years old, not disclosing sexual attraction to men, never having had anal intercourse with a man, having a female partner, living in a rural area, and certain European sub-regions or countries of residence increased the likelihood of being screened in blood establishments. DISCUSSION: In spite of deferral policies, MSM are screened for HIV in the context of blood donations. Gay-friendly testing services are rare in rural areas, and young men might be reluctant to disclose their sexual orientation. Recent developments, such as home sampling, might offer new testing possibilities for those not reached by established services yet wishing to know their HIV status. Donor selection procedures should be improved. Both interventions might help to further reduce the risk of transfusion-transmitted infections.

Good Feasibility of the New German Blood Donor Questionnaire.

BACKGROUND: We assessed the effect of the uniform donor questionnaire (UDQ) on deferral rates in first-time and repeat donors. We focused on the introduced question about unprotected sexual contact with a new partner. Another goal was a stratified comparison of the deferral rates of the donor questionnaire (DQ) and UDQ. METHODS: Data on donors and deferrals using the DQ and UDQ were collected at four blood establishments. The comparison included a 2-year period by questionnaire version. For the comparison of the questionnaires, an adjusted multinomial logistic regression was performed. RESULTS: The analysis included 260,848 donations. First-time (FTD) and repeat donations (RD) showed higher deferral rates with the UDQ (FTD +5.4%, RD +1.4%). Deferral due to a new partner was 3.0% in first-time and 0.4% in repeat donors. The majority of these occurred in the youngest age groups. The most frequent deferral criterion was 'disease' (5.1%). CONCLUSION: The regression revealed stronger predictors for deferral than the questionnaire version. Especially younger age carried a higher and independent risk for deferral. The additional deferrals of mainly young first-time donors due to a new sexual partner may identify those donors with potential heterosexual risk behavior who would otherwise not be identified.

Selecting the Right Donors - Still a Challenge: Development of a Uniform Donor Questionnaire in Germany.

The selection of blood donors includes the assessment of the individual's health and medical history by using a donor questionnaire (DQ) in order to identify persons whose donation could present a health risk to recipients or to themselves. This way, DQs provide one layer of blood safety and contribute to the high safety profile of blood components currently available in Germany. This review reports the development of a new uniform questionnaire in Germany and its first evaluation using a field test approach. This development is set in context with the international experiences regarding donor selection and prospective challenges.