A prospective cohort study of SARS-CoV-2 infection-induced seroconversion and disease incidence in German healthcare workers before and during the rollout of COVID-19 vaccines.

We assessed the seroepidemiology of SARS-CoV-2 infection and the incidence of coronavirus disease 2019 (COVID-19) before and during the rollout of COVID-19 vaccines, in a prospective observational cohort study on healthcare workers (HCWs) in a large tertiary hospital in Mainz, Germany. Antibody status was assessed during six visits between September 2020 and February 2022. Self-reported symptoms were collected using a smartphone application; symptomatic HCWs were tested using real-time polymerase chain reaction (RT-PCR) assays for SARS-CoV-2. Rates of virologically confirmed and severe COVID-19 were estimated using the U.S. Food and Drug Administration (FDA) and Coalition for Epidemic Preparedness Innovations (CEPI) case definitions, respectively, and were contrasted to background community transmission and circulating SARS-CoV-2 variants. A total of 3665 HCWs were enrolled (mean follow-up time: 18 months); 97 met the FDA definition of virologically confirmed COVID-19 (incidence rate (IR) 2.3/1000 person-months (PMs), one severe case). Most cases reported ≥2 symptoms, commonly, cough and anosmia or ageusia. Overall, 263 individuals seroconverted (IR 6.6/1000 PMs-2.9 times the estimated IR of COVID-19), indicating many cases were missed, either due to asymptomatic infections or to an atypical presentation of symptoms. A triphasic trend in anti-SARS-CoV-2 seroprevalence and seroconversion was observed, with an initial increase following the rollout of COVID-19 vaccines, a two-fold decline six months later, and finally a six-fold increase by the end of the study when Omicron was the dominant circulating variant. Despite the increase in infection rates at the end of the study due to the circulation of the Omicron variant, the infection and disease rates observed were lower than the published estimates in HCWs and rates in the general local population. Preferential vaccination of HCWs and the strict monitoring program for SARS-CoV-2 infection are the most likely reasons for the successful control of COVID-19 in this high-risk population.

Long-Term, CD4+ Memory T Cell Response to SARS-CoV-2.

The first cases of coronavirus disease-19 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were reported by Chinese authorities at the end of 2019. The disease spread quickly and was declared a global pandemic shortly thereafter. To respond effectively to infection and prevent viral spread, it is important to delineate the factors that affect protective immunity. Herein, a cohort of convalescent healthcare workers was recruited and their immune responses were studied over a period of 3 to 9 months following the onset of symptoms. A cross-reactive T cell response to SARS-CoV-2 and endemic coronaviruses, i.e., OC43 and NL63, was demonstrated in the infected, convalescent cohort, as well as a cohort composed of unexposed individuals. The convalescent cohort, however, displayed an increased number of SARS-CoV-2-specific CD4+ T cells relative to the unexposed group. Moreover, unlike humoral immunity and quickly decreasing antibody titers, T cell immunity in convalescent individuals was maintained and stable throughout the study period. This study also suggests that, based on the higher CD4 T cell memory response against nucleocapsid antigen, future vaccine designs may include nucleocapsid as an additional antigen along with the spike protein.

Longitudinal Study of the Signal Strength in two Serologic Assays for Detection of SARS-CoV-2 Specific Antibodies.

BACKGROUND: In the course of the current SARS-CoV-2 pandemic, antibody assays provide an important means for guidance of public health efforts. Thus, characterization of the course of antibody signals on different widely used assays is needed. METHODS: We selected 25 PCR-confirmed SARS-CoV-2 cases among 3,273 healthcare workers and measured the course of the antibody signal using the Abbott Architect SARS-CoV-2 IgG assay and the Roche Elecsys® Anti-SARS-CoV-2 immunoassay. The signal strength was then modelled using linear mixed models adjusted for age. RESULTS: Since first sampling, the assay signal decreased per day in the Abbott assay (standardized slope (ß) = -0.46, 95% CI = -0.54 to -0.39). In contrast, an increase in the signal was ascertained by the Roche immunoassay per day (ß = 0.25, 95% CI = 0.09 to 0.41). CONCLUSIONS: Roche Elecsys® Anti-SARS-CoV-2 immunoassay may exhibit greater sensitivity in detecting SARS-CoV-2-specific antibodies in individuals in late stages of postinfection.

mRNA-Based Vaccines.

Increases in the world's population and population density promote the spread of emerging pathogens. Vaccines are the most cost-effective means of preventing this spread. Traditional methods used to identify and produce new vaccines are not adequate, in most instances, to ensure global protection. New technologies are urgently needed to expedite large scale vaccine development. mRNA-based vaccines promise to meet this need. mRNA-based vaccines exhibit a number of potential advantages relative to conventional vaccines, namely they (1) involve neither infectious elements nor a risk of stable integration into the host cell genome; (2) generate humoral and cell-mediated immunity; (3) are well-tolerated by healthy individuals; and (4) are less expensive and produced more rapidly by processes that are readily standardized and scaled-up, improving responsiveness to large emerging outbreaks. Multiple mRNA vaccine platforms have demonstrated efficacy in preventing infectious diseases and treating several types of cancers in humans as well as animal models. This review describes the factors that contribute to maximizing the production of effective mRNA vaccine transcripts and delivery systems, and the clinical applications are discussed in detail.

Prevalence of Severe Acute Respiratory Syndrome Coronavirus-2-specific Antibodies in German Blood Donors during the COVID-19 Pandemic.

BACKGROUND: Coronavirus disease-2019 (COVID-19) is a respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While RT-PCR assays are used routinely to diagnose active COVID-19, serological testing offers a means of identifying individuals who previously experienced asymptomatic infections, as well as those who experienced symptomatic infections but no longer carry the virus. METHODS: The presence of SARS-CoV-2 IgG-positive antibodies in the sera of 673 blood donors residing in south-western Germany before and 3,880 donors after the advent of the COVID-19 pandemic was determined and confirmed using two highly sensitive serological tests. RESULTS: Approximately 0.40% of the donors assessed during the COVID-19 pandemic possessed SARS-CoV-2 IgG-positive antibodies, decidedly fewer than the percentage of SARS-CoV-2-infected individuals determined by real-time RT-PCR nationwide. CONCLUSIONS: These findings confirm the efficacy serological testing in identifying asymptomatic COVID-19 patients.

Containment of a Large SARS-CoV-2 Outbreak Among Healthcare Workers in a Pediatric Intensive Care Unit.

OBJECTIVE: Healthcare workers (HCWs) are particularly exposed SARS-CoV-2 because they are critical in preventing viral transmission and treating COVID-19 patients. Within HCWs, personnel of intensive care units (ICUs) are at the forefront of treating patients with a severe course of COVID-19 infection and therefore represent an extremely vulnerable group. Thus, our objective is to contribute to establish means of infection control protecting HCWs in the frontline of the current pandemic. DESIGN: An outbreak of SARS-CoV-2 was detected and contained in a pediatric ICU (PICU). The first positive case was identified with a point-of-care diagnostic system on site. Real-time PCR-based testing systems from self-collected nasopharyngeal samples swabs were used to test for viral RNA of SARS-CoV-2 in the follow-up. SETTING: PICU within a tertiary university hospital in Germany. PARTICIPANTS: Healthcare workers of the PICU. INTERVENTIONS: Positive HCWs were sent into quarantine. Containment measures were implemented including wearing of surgical-masks, physical distancing and systematic testing. RESULTS: Among 432 HCWs, 91 (25%) were tested. Forty-five percent reported symptoms corresponding to characteristics of COVID-19. Of those, only 19,5% (8 HCWs) were tested positive for SARS-CoV-2. No infection occurred outside the PICU. After the implementation of containment measures, viral transmission was stopped. CONCLUSIONS: In the present study, a large outbreak within a team of healthcare workers of a PICU, affecting almost one fifth of the entire personnel is documented, along with detailed insights about how the outbreak was contained and how operability of the unit was maintained.

Seroprevalence and Seroconversion of Cytomegalovirus in a Large Group of Healthy, German Blood Donors: Potential Contribution to Transfusion Transmitted Infections.

BACKGROUND: Immunocompromised patients are at increased risk of morbidity and mortality due to transfusion transmitted cytomegalovirus (CMV) infections. To avoid or minimize such risk, clinicians working in the field continually monitor the changing epidemiology of CMV infections. MATERIALS AND METHODS: A total of 234,192 blood donations obtained from 44,779 donors were tested. CMV seroprevalence and antibody conversion rates were determined over a 3-year period. RESULTS: A significant percentage (37.5%) of all male and female blood donors tested seropositive. Both age and gender were risk factors for CMV infection. A total of 177 seroconversions (0.4% of donors) were identified. The highest antibody conversion rate occurred among men between 30 and 39 years of age; women did not experience a similar peak in antibody conversion rate. Approximately 10% of infected blood donors were identified by CMV DNA testing prior to seroconversion. CONCLUSIONS: The high rates of seroprevalence and seroconversion and the identification of a significant number of CMV DNA-positive (infected) blood donors prior to seroconversion indicate that the routine testing of blood samples for CMV DNA could reduce the potential risk of CMV transmission to high-risk patients.

[Vaccination As A Risk? - Why People and Their Children Do Not Get Vaccinated]. / Risiko Impfen?

Skepticism about vaccination is not new, but the perception of vaccine-related risks has changed in recent decades. In addition to aspects such as knowledge about vaccines, trust in medical care structures and political institutions, socio-economic, cultural and religious views also play an important role. These factors differ significantly worldwide and regionally. In almost all surveys, confidence in vaccines and/or the healthcare system is identified as essential for a positive vaccination decision. Confidence in vaccines correlates with the assessment of the specific individual disease risk and the potential side effects of the vaccines. Subjective perception of risk seldom corresponds to objectively measurable facts. Rather, it is distorted by individual perception in both directions (underestimation and overestimation). Transparent, science-based communication is helpful in promoting and maintaining trust in healthcare. Pediatricians and family physicians are the most important confidants for parents on questions about health care and vaccination recommendations.

Norovirus Gastroenteritis among Hospitalized Patients, Germany, 2007-2012.

We estimated numbers of hospitalizations for norovirus gastroenteritis (NGE) and associated medical costs in Germany, where norovirus testing is high because reimbursement is affected. We extracted aggregate data for patients hospitalized with a primary or secondary code from the International Classification of Diseases, 10th Revision (ICD-10), NGE diagnosis during 2007-2012 from the German Federal Statistics Office. We assessed reliability of the coding system in patient records from a large academic hospital. Approximately 53,000-90,000 NGE hospitalizations occurred annually in Germany (21,000-33,000 with primary and 32,000-57,000 with secondary ICD-10-coded NGE diagnoses). Rates of hospitalization with NGE as primary diagnosis were highest in children <2 years of age; rates of hospitalization with NGE as secondary diagnosis were highest in adults >85 years of age. The average annual reimbursed direct medical cost of NGE hospitalizations was €31-43 million. Among patients with a NGE ICD-10 code, 87.6% had positive norovirus laboratory results.

MMR and MMRV vaccines.

Measles, mumps, rubella and varicella are viral infections which can implicate seriously long-term sequelae of infected individuals or even the unborn child. Vaccines against the individual diseases have long been available. Global measles vaccination is estimated to have prevented more than 20million deaths during 2000-2015. During the same time period, measles incidence decreased from 146 to 36 cases per million populations. Today vaccinations against measles, mumps, rubella and varicella are now carried out mainly with combination vaccines. These are today known as immunogenic and safe. MMRV had similar immunogenicity and overall safety profiles to MMR administered with or without varicella vaccine. This issue provides a review of the different vaccines, mode of administration, catch up immunization and postexposure prophylaxis as well as contraindications and adverse effects of the immunization against measles, mumps, rubella, and varicella. The article presents an overview of important information of preventing these diseases with a focus on the existing combination vaccines.

Disease Burden of Rotavirus Gastroenteritis in Children Residing in Germany: A Retrospective, Hospital-based Surveillance.

BACKGROUND: Representative, population-based epidemiologic data for gastroenteritis caused by rotavirus (RV) are rare. RV vaccines were first licensed in Europe in 2006 and recommended in 5 western federal states in 2008 or thereafter. This study establishes a baseline for assessing the impact of vaccination and delineates the RV disease burden in Germany today. METHODS: Nationwide data obtained from hospitals for children 0 to 10 years of age and transferred to the Federal Statistical Office were analyzed retrospectively. Acute gastroenteritis cases because of RV were identified by the International Classification of Diseases code (ICD-10) combined with the referring diagnosis-related group code. Coding quality was validated by random sampling the patient records (n=1003). Crude and age-standardized rates per 100,000 person-years were calculated. The rate ratios of seasonal effects and recommended immunization adjusted for year, federal state and age were estimated using Poisson regression. RESULTS: Between 2005 and 2010, 5,843,730 children were hospitalized; 520,606 cases were hospitalized because of acute gastroenteritis. RV caused 152,636 of these cases or an age-standardized rate of 302 hospitalizations per 100,000 person-years. Rates were slightly higher in boys than girls, decreased with age, and differed by federal state, year and season. Rate ratios decreased in those western federal states that recommended immunization and were inversely associated with vaccine doses sold. CONCLUSIONS: With an average of 25,440 children hospitalized yearly, RV infection has a great impact on the German healthcare system. Our findings indicate that RV immunization will lead to a decline in in-patient treatment and associated costs.

The burden of norovirus disease in children in the European Union.

BACKGROUND: Noroviruses (NoVs) are the leading cause of acute gastroenteritis across all age groups. Because a vaccine is in clinical development, burden of disease data are required to guide the eventual introduction of this vaccine. In this study, we estimate the burden of NoV disease in children less than 5 years of age in the European Union (EU). METHODS: We carried out a literature search using PubMed to identify studies providing incidence or prevalence data for NoV disease in the EU. We applied the pooled average NoV incidence and prevalence rates to the EU population less than 5 years of age to obtain the annual number of NoV illnesses, medical visits, hospitalizations and deaths occurring in the EU among children younger than 5 years. RESULTS: Data from 12 studies were included. We estimate that NoV infection may cause up to 5.7 million illnesses in the community, 800,000 medical visits, 53,000 hospitalizations and 102 deaths every year in children younger than 5 years in the EU. CONCLUSION: The burden of NoV disease in children in the EU is substantial, and will grow in relative importance as rotavirus (RV) vaccines are rolled out in the EU. This burden of disease is comparable with the burden of RV disease in the EU before RV vaccine introduction. More country-specific studies are needed to better assess this burden and guide the potential introduction of a vaccine against NoV at the national level.

Risk of febrile convulsions after MMRV vaccination in comparison to MMR or MMR+V vaccination.

BACKGROUND: In July 2006, Priorix-Tetra™, a combined measles-mumps-rubella-varicella (MMRV) vaccine, was licensed in Germany. Since a postlicensure study had shown a more than twofold elevated risk of febrile convulsions (FC) after first dose vaccination with the combined MMRV vaccine ProQuad(®) compared to separately administered MMR and V vaccines (MMR+V), the Paul-Ehrlich-Institute, the German regulatory agency for vaccine licensing and safety, requested a study investigating the risk of FC for Priorix-Tetra™. METHODS: We performed a matched cohort study based on claims data of more than 17 million insurees in the German Pharmacoepidemiological Research Database. All children born between 01.01.2004 and 31.12.2008 who received a 1st dose of MMRV vaccine were matched to children vaccinated with MMR, MMR+V and MMR or MMR+V (combined group), respectively, by sex, age, month of vaccination and statutory health insurance. The primary outcome was defined as hospitalization with a diagnosis of FC without any alternative plausible cause of FC, e.g. an infection or neurological condition, coded as main discharge diagnosis. The secondary outcome excluded only neurological conditions to provide a more comparable outcome definition to the one used in the ProQuad(®) study. Numbers needed to harm (NNH), risk ratios and confounder adjusted odds ratios (ORs) with 95% CIs were estimated to compare the exposure groups. RESULTS: In the main risk period 5-12 days after immunization, the adjusted ORs of the primary endpoint for immunization with MMRV vaccine relative to the comparator vaccine indicated in brackets were 4.1 [95% CI 1.3-12.7; MMR], 3.5 [0.7-19.0; MMR+V], and 4.1 [1.5-11.1; MMR and MMR+V]. The corresponding ORs for the secondary outcome were 2.3 [1.4-3.9; MMR], 1.5 [0.8-2.9; MMR+V] and 2.4 [1.5-3.9; MMR and MMR+V]. CONCLUSIONS: This study in children younger than 5 years, 90% of them between 11 and 23 months, shows a risk of FC similar in magnitude for Priorix-Tetra™ as has previously been reported for ProQuad(®) suggesting a class effect for these quadrivalent vaccines.

Sirolimus treatment of severe PTEN hamartoma tumor syndrome: case report and in vitro studies.

BACKGROUND: Phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) is caused by germ line mutations in the PTEN gene. Symptoms include cancer predisposition, immune deviations, and lipomas/lipomatosis. No causal standard therapy is available. We describe a therapeutic attempt with the mammalian target of rapamycin (mTOR) inhibitor sirolimus for a PHTS patient suffering from thymus hyperplasia and lipomatosis. We furthermore assessed the in vitro effects of sirolimus and other inhibitors on lipoma cells of the patient. METHODS: The patient underwent clinical and blood examinations and whole-body magnetic resonance imaging to assess tumor sizes. Lipoma cells of the patient were incubated with inhibitors of the phosphoinositide-3-kinase (PI3K)/AKT/mTOR signaling pathway to analyze the effects on proliferation, adipocyte differentiation, and survival in vitro. RESULTS: Sirolimus treatment improved somatic growth and reduced thymus volume. These effects diminished over the treatment period of 19 mo. Sirolimus decreased lipoma cell proliferation and adipocyte differentiation in vitro but did not cause apoptosis. PI3K and AKT inhibitors induced apoptosis significantly. CONCLUSION: Sirolimus treatment led to an improvement of the patient's clinical status and a transient reduction of the thymus. Our in vitro findings point to PI3K and AKT inhibitors as potential treatment options for patients with severe forms of PHTS.

Comparative effects of carrier proteins on vaccine-induced immune response.

The efficacy of vaccines against major encapsulated bacterial pathogens -Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae type b (Hib) - has been significantly enhanced by conjugating the respective polysaccharides with different carrier proteins: diphtheria toxoid; non-toxic cross-reactive material of diphtheria toxin(197), tetanus toxoid, N. meningitidis outer membrane protein, and non-typeable H. influenzae-derived protein D. Hib, meningococcal, and pneumococcal conjugate vaccines have shown good safety and immunogenicity profiles regardless of the carrier protein used, although data are conflicting as to which carrier protein is the most immunogenic. Coadministration of conjugate vaccines bearing the same carrier protein has the potential for inducing either positive or negative effects on vaccine immunogenicity (immune interference). Clinical studies on the coadministration of conjugate vaccines reveal conflicting data with respect to immune interference and vaccine efficacy.

Prospective multinational study of pertussis infection in hospitalized infants and their household contacts.

BACKGROUND: Increased incidence of pertussis has been noted among infants too young to be immunized. We studied the disease burden of pertussis in pediatric intensive care units and the source of infection in several Asian, European and Latin American countries. METHODS: The study was conducted in 7 countries from September 2001 to January 2004. Children <1 year of age were enrolled from pediatric intensive care units (PICU) and pediatric wards if they presented with respiratory failure, apnea, bradycardia, or cough accompanied by paroxysms, vomiting, whoop or cyanosis. Household members of pertussis-positive index cases were asked to answer a questionnaire and provide diagnostic specimens. RESULTS: Pertussis was confirmed in 99 infants (12%) of 823 infants included in the analysis: 10 of 90 (11%) in Brazil, 9 of 88 (10%) in Costa Rica, 11 of 145 (8%) in Germany, 13 of 147 (9%) in Singapore, 29 of 67 (43%) in Spain, 2 of 86 (2%) in Taiwan and 25 of 200 (13%) in Uruguay. However, sensitivity analysis indicated that these figures were conservative. The mean (+/- SD) average age of infection was 2.6 +/- 2.2 months. Pertussis was found among 96 of 269 (36%) of household contacts investigated. At least one household contact was identified as the source of infection in 24 of 88 (27%) of the PICU cases and mothers were identified as being the most frequent source of infection. CONCLUSION: Although regional differences exist, severe pertussis represents a considerable global disease burden. Since most infants are infected before vaccination and concomitant protection is completed, household contacts should be targeted for booster vaccination to reduce the pertussis reservoir.