Waning of SARS-CoV-2 IgG antibodies after vaccination: first results from the CoMoLo follow-up 2021

Background

In 2020, the study “Corona-Monitoring Lokal” (CoMoLo) assessed seroprevalences of SARS-CoV-2 IgG antibodies in four study locations that were particularly affected by outbreaks in the early stages of the pandemic in Germany. One of the objectives of the 2021 follow-up was to examine the development of immunological parameters over time, including the extent of IgG antibody waning after vaccination.

Methods

Venous blood specimens were collected from a sample of initial study participants over a 2-week period between May and October 2021, with an oversampling of seropositive or previously infected individuals. Levels of IgG antibodies to the SARS-CoV-2 spike protein were measured from serum using Anti-SARS-CoV-2-QuantiVac-ELISA (IgG) tests by Euroimmun. Information on SARS-CoV-2 vaccinations or known infections was collected via online questionnaires or telephone interviews.

Results

A total of 3328 participants (74% response) gave blood specimens for this follow-up study, with questionnaire information available for 2843 (85%) of these. Preliminary analyses suggest that in participants who had received two doses of a vaccine more than 3 weeks before giving blood (n = 1583), IgG levels decreased exponentially by about 9.8% (95%CI 9.1% - 10.4%) with each additional week since the last dose, when controlling for age, sex, and type of vaccine. There was evidence of this waning effect differing by vaccine type. Antibody levels also appear to decline with increasing age, according to preliminary results. Final results of the linear model used to assess the dynamics and predictive factors of antibody levels will be reported.

Conclusions

This follow-up study will add evidence to an improved understanding of antibody waning after SARS-CoV-2 vaccination. Preliminary results are in line with international studies and may be helpful for discussions on potential benefits of further vaccinations in Germany.

Key messages

• Antibodies induced by COVID-19 vaccination wane over time. The magnitude of this effect differs by vaccine type. Antibodies also decreased with increasing age.

• Our results may be helpful for discussions on potential benefits of further COVID-19 vaccinations in Germany.

SARS-CoV-2 Seroprevalence in Germany: results from the second wave of the RKI-SOEP study

Introduction

The first wave of the “Corona Monitoring bundesweit” (RKI-SOEP) study showed that shortly before the start of the German vaccination program only about 2% of adults (> 18 years) had already experienced SARS-CoV-2 infection and more than half of these cases had been detected and notified. The objectives of the second wave of this study are to further investigate the spread of SARS-CoV-2 in Germanýs population aged over 14 years. It aims to determine the seroprevalence of infection- and vaccine-induced IgG antibodies against SARS-CoV-2. Finally, it examines health, demographic and socioeconomic risk and protective factors for infection and vaccine acceptance.

Methods

From November 2021 to February 2022, the second wave of this cross-sectional study collected biospecimens (capillary blood samples) and interview data, including information on infection and vaccination, from a nationwide population sample drawn from the German Socio-Economic Panel (SOEP). The dried self-collected blood samples were then analyzed for the detection of SARS-CoV-2 IgG antibodies by Euroimmun ELISA assay.

Results

Based on preliminary, unweighted data of around 11,000 participants aged >14 years (52% response rate), we expect the final seroprevalence of SARS-CoV-2 antibodies to be in the range of 80 to 90%. Thus, around 10 to 20% of the German population may still be susceptible to a severe disease progression because they are neither infected nor vaccinated. Final results, weighted for non-response and adjusted for test sensitivity and specificity, will be presented.

Conclusions

The RKI-SOEP-2 study will be pivotal in both, contributing to an improved understanding of SARS-CoV-2 propagation in different regional and sub-group settings and in identifying vulnerable target groups that need to be protected against future infections.

Key messages

• Dried blood self-sampling in a nationwide sample is a robust tool to estimate seroprevalence at a population level.

• As of February 2022, presumably 80 to 90% of the German population has previously been infected and/or vaccinated against SARS-CoV-2.

[The first KiGGS follow-up (KiGGS Wave 1): study conduct, sample design, and response]

The "German Health Interview and Examination Survey for Children and Adolescents" (KiGGS) is part of the health monitoring system of the Robert Koch Institute (RKI). Following the KiGGS baseline study (2003 - 06), which comprised interviews and physical examinations of 0- to 17-year-old participants, KiGGS Wave 1 (2009 - 2012) was carried out as a telephone-based survey. In addition to providing longitudinal data, a second essential aim of KiGGS is to regularly provide population-based cross-sectional data on the health situation of children and adolescents aged 0-17 years living in Germany. Therefore, the study population of KiGGS Wave 1 consists of re-invited participants from the baseline study (KiGGS cohort), supplemented by newly invited children aged 0-6 years. The newly invited participants were randomly chosen from local population registries in the 167 baseline sample points. This method was chosen to supplement the sample with younger age groups. This article focuses on the age groups from 0 to 17 years, which are relevant for prevalence estimations among children and adolescents. In total 12,368 children and adolescents took part; among them 4,455 newly invited and 7,913 re-invited participants (response 38.8 and 72.9%, respectively). A comparison of the net sample with the resident German population (0-17 years) regarding particular population characteristics and an analysis of the relationship between the re-participation rate and certain characteristics collected in the baseline study (7-17 years) suggest a mostly unbiased sample. To account for certain aspects of the population and nonresponse, cross-sectional and trend analyses were partially corrected by weighting factors.

[The first wave of the German Health Interview and Examination Survey for Adults (DEGS1): sample design, response, weighting and representativeness]

The "German Health Interview and Examination Survey for Adults" (DEGS) is part of the health monitoring program of the Robert Koch Institute (RKI) and is designed as a combined cross-sectional and longitudinal survey. The first wave (DEGS1; 2008-2011) comprised interviews and physical examinations. The target population were 18- to 79-year olds living in Germany. The mixed design consisted of a new sample randomly chosen from local population registries which was supplemented by participants from the "German National Health Interview and Examination Survey 1998" (GNHIES98). In total, 8,152 persons took part, among them 4,193 newly invited (response 42%) and 3,959 who had previously taken part in GNHIES98 (response 62%). 7,238 participants visited one of the 180 local study centres, 914 took part in the interview-only programme. The comparison of the net sample with the group of non-participants and with the resident population of Germany suggests a high representativeness regarding various attributes. To account for certain aspects of the population structure cross-sectional, trend and longitudinal analyses are corrected by weighting factors. Furthermore, different participation probabilities of the former participants of GNHIES98 are compensated for. An English full-text version of this article is available at SpringerLink as supplemental.

Gestational diabetes and cardiovascular risk factors in the offspring: results from a cross-sectional study

BACKGROUND

While the association of gestational diabetes mellitus and abnormal glucose tolerance is beyond doubt, its associations with other cardiovascular disease risk factors in the offspring are less clearly established. Some of these associations, in particular overweight in the offspring, might be confounded by maternal overweight.

METHODS

Data on 12,542 children in the age of 3-17 years with full information about gestational diabetes mellitus and maternal BMI were available from the German nationwide KiGGS study. We calculated linear and logistic regression models for measurements of body composition, blood pressure, HbA(1c) and cholesterol values in the offspring with gestational diabetes mellitus as the explanatory variable, with and without adjustment for maternal BMI.

RESULTS

The prevalence of gestational diabetes mellitus in the dataset was 2.2%. Unadjusted regression analyses suggested weak positive effects of gestational diabetes mellitus on body composition measurements [e.g. a mean increase in BMI standard deviation scores (SDS) of 0.17 units (95% confidence interval: 0.03, 0.30)]. After adjustment for maternal BMI, the observed associations almost disappeared [e.g. BMI SDS: 0.07 (-0.06, 0.20)]. With respect to blood pressure and cholesterol, no potential effects of gestational diabetes mellitus were observed in both unadjusted and adjusted models.

CONCLUSION

Gestational diabetes mellitus does not appear to have a relevant effect on cardiovascular disease correlates such as blood pressure or cholesterol levels in children, and the potential effect of gestational diabetes mellitus on body composition seems to be widely explainable by maternal BMI.

[Overweight and obesity in children and adolescents in Germany]

The increasing prevalence of overweight and obesity is a reason for concern not only in Germany but also in other countries. There are various methods and data sources that can be used to assess the extent of this public health problem. The present publication gives an overview of the reference systems that are in use in Germany to assess body mass index (BMI), which is calculated from height and weight, and an overview from several data sources: the school entry examinations, the HBSC study of the WHO, and the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). Current prevalence estimates are based on the KiGGS survey, which found that, based on the Kromeyer-Hauschild reference system, 14.8% of the children and adolescents in Germany aged 2-17 years are overweight, including 6.1% suffering from obesity. In absolute numbers referring to the most recent population numbers, this corresponds to 1.7 million overweight children and adolescents in Germany aged 2 years and older, 750,000 of whom are obese. This description of the status quo represents the benchmark for all future studies of BMI that aim at assessing temporal trends and, thus, the efficacy of national prevention and intervention programs. Regular examinations of certain age groups of children and adolescents in Germany, such as the school entry examinations, can be used for the assessment of temporal trends, if certain standards are followed during the examination. Studies that rely on self-reported height and weight instead of measurements, such as the German part of the HBSC study, however, need a correction based on the subjective body perception. The KiGGS participants themselves are also subject to follow-up interviews and examinations. Thus, it will be possible to regularly update the assessment of the prevalence of overweight and obesity. The Kromeyer-Hauschild reference system should not be replaced by the KiGGS BMI data, in order not to artificially lower the prevalences of overweight and obesity. It should, however, not be used for children below 2 years of age.

Changes of menopausal hormone therapy use pattern since 2000: results of the Berlin Spandau Longitudinal Health Study

BACKGROUND

There are virtually no prospective cohort studies in Germany regarding the changes of menopausal hormone therapy (HT) use pattern and factors associated with HT discontinuation after the release of the Women's Health Initiative (WHI) trial results.

METHODS

We assessed HT prevalence and use pattern as well as factors associated with HT discontinuation in a cohort of 903 women 40 years of age and older, who participated in two consecutive follow-up visits in a 20-year prospective health study from July 2000 to February and from August 2002 to December 2004.

RESULTS

Overall, the prevalence of HT users in the cohort declined significantly from 35.4% in 2000-2002 to 22.5% in 2002-2004. Adjusting for aging of the population, a statistically significant decrease in HT user prevalence was consistently observed across subgroups of HT users defined by type and duration of HT use. The decline was most pronounced with respect to women using combined estrogen-progestin regimens (-10.5%), higher-dose estrogens (-11.6%), oral preparations (-11.1%), as well as long-term HT users (-8.4%). The prevalence of women indicating HT use for climacteric symptoms decreased significantly (-12.4%), whereas the prevalence of women reporting use of HT for the prevention of osteoporosis increased (+1.8%) significantly. Irrespective of hysterectomy status, half of the women who continued HT changed their HT preparations and switched to lower estrogen doses (11.5%), topical estrogens (8.2%), or phytohormones (3.8%). We did not observe any significant differences between women who continued and discontinued HT regarding health-related characteristics of the study population as of 2000-2002. However, women seeing a gynecologist in the 12 months preceding the 2002-2004 visit were significantly less likely to discontinue HT use in bivariate and multivariate analyses.

CONCLUSIONS

Substantial declines in HT user prevalence as well as changes in HT use patterns to lower-dose estrogen preparations and non-oral routes of administration are likely to reflect effects of the publication of the WHI results. Consulting a gynecologist appeared to be relevant for a woman's decision to continue HT.

[The prevalence of overweight and obese children and adolescents living in Germany. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]

Overweight and obesity are an increasing problem: worldwide, for Germany and for children and adolescents. Until now there have been no representative and age-specific assessments of the prevalence of obesity among children and adolescents in Germany. Thus, the standardised height and weight measurements gathered in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) have, for the first time, provided national, representative data about overweight and obesity in young people. The terms 'overweight' and 'obese' are defined based on percentiles of the body mass index (BMI) of the Kromeyer-Hauschild reference system. Of children and adolescents between the ages of 3 and 17, 15% exceed the 90th BMI percentile of the reference data and are thus overweight, 6.3% exceed the 97th BMI percentile and thus suffer from obesity by this definition. The proportion of overweight rises from 9% of 3-6-year-olds to 15% of 7-10-year-olds and 17% of 14-17-year-olds. The prevalence of obesity is 2.9%, 6.4% and 8.5% for the same age groups respectively. No clear differences between boys and girls or between East and West Germany are detected. Children are at a higher risk of being overweight or obese if they have a lower socioeconomic status, have a migration background, or have mothers who are also overweight.

Das Landesmodul Schleswig-Holstein im Rahmen des Kinder- und Jugendgesundheitssurveys (KiGGS)

From August 2004 to June 2005, the Robert Koch Institute conducted the fieldwork for the Schleswig-Holstein module of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). The KiGGS study is a nationwide representative survey of the health of children and adolescents aged 0 to 17 years. By increasing the sample size in the age group 11 to 17 years in Schleswig-Holstein, the module study generated information which is representative for this federal state. For this end, further 18 locations in this federal state were included in the module study in addition to the existing 5 study locations in Schleswig-Holstein and a study programme which was slightly reduced compared to the core survey was realised. A total of 1,931 subjects were examined in Schleswig-Holstein: 1,730 in the federal state module and 201 in the core survey. The participation rate was 69.5% in the module study. The percentage of quality-neutral drop-outs was 4.0%. The federal state module was funded by the Ministry of Social Welfare, Health, Family, Youth and Seniors of the Federal State of Schleswig-Holstein. The data collected were used for health reporting on a federal state level.

[Sexual maturation of children and adolescents in Germany. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]

Following the standstill in maturity acceleration in the eighties of the twentieth century, now a further shift in maturity development towards younger ages is the issue of an international and also German discussion. The collection of sexual maturity data in boys and girls as part of the nationwide German Health Interview and Examination Survey for Children and Adolescents (KiGGS) is intended to pro vide population-representative information on sexual maturation and to evaluate associations between maturity status and selected health and social data. Girls were interviewed regarding their first menstrual period (menarche) and boys regarding voice change (status-quo method). Pubic hair was self-assessed by children and adolescents from 10 to 17 years of age, based on drawings of Tanner's defined developmental stages. The median age for menarche, for voice change and pubic hair stages were calculated using a logit model. At an age of 10 years, 42.4 % of girls and 35.7 % of boys report the development of pubic hair. At 17 years of age, the majority of girls and boys have reached the stages PH5 (girls 57.5 %, boys 47.8 %) and PH6 (girls 23.6 %, boys 46.5 %) according to Tanner. The average age for each pubic hair stage is lower in girls (PH2 10.8; PH3 11.7; PH4 12.3; PH5 13.4 years) than in boys (PH2 10.9; PH3 12.6; PH4 13.4; PH5 14.1). The median age at menarche is 12.8 years, the median for voice change (voice low) 15.1 years. Significant differences in age at menarche are found in girls depending on socioeconomic status (12.7/12.9/13.0 years for low/middle/high status) and between girls with and without migration background (12.5/12.9 years). No differences in age at menarche can be seen between East and West Germany or cities and rural areas. The association between maturity status and BMI is more pronounced in girls than in boys. Overall, the onset of maturity development in German children and adolescents is not significantly earlier than in other European studies.

Messung soziodemographischer Merkmale im Kinder- und Jugendgesundheitssurvey (KiGGS) und ihre Bedeutung am Beispiel der Einschätzung des allgemeinen Gesundheitszustands

The German Health Interview and Examination Survey for Children and Adolescents (KiGGS) was conducted from May 2003 to May 2006 by the Robert Koch Institute in 167 communities representative of Germany. By collecting comprehensive and nationally representative data on the health status of children and adolescents aged 0 to 17 years, the study aimed to fill a longstanding evidence gap. Data from 17,641 study participants will be analysed in a timely and systematic manner by the Robert Koch Institute. Initially mainly descriptive analyses as presented in the current special issue on the KiGGS study, provide information on the distribution of main health characteristics according to sociodemographic key variables, including age, sex, region of residence (former East/West Germany), social status, and migrant background. We report here the rationale for a standard set of stratifying variables and the operationalisation of composite variables. Furthermore, we illustrate the public health relevance of the observed group differences using the example of an important health indicator: parents' evaluation of their children's general state of health.

Der Kinder- und Jugendgesundheitssurvey (KiGGS): Datenmanagement

In the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), comprehensive, nationwide representative data on the state of health of children and adolescents were collected for the first time. During the 3-year data collection phase of the survey, 17,641 subjects were examined and interviewed and approx. 1,500 items were recorded. Data management was not limited to survey data collection, administration and quality assurance alone, but also comprised the provision of tools for the management and control of process data, as well as for managing survey-specific business processes. In the context of the KiGGS study, numerous components for supporting the extensive and complex processes were developed for the study staff. Here the primary focus was on subject and sample point administration, scheduling, sampling, reporting, field logistics and laboratory data management. Thanks to the computer-based processing of routine tasks involved in the organisation of the field work, ease of work and project progress control were enhanced significantly. To some extent, KiGGS-specific components have already been used in other studies and only minor adaptations were needed for the transfer. The main emphasis with regards to survey data management was on the standardisation of methods for data processing, data control and data cleaning. Here, a wealth of previous experiences was available as a starting point. The established quality assurance methods were standardised to a large extent and partly automated and complemented by data base tools for the management and documentation of survey instruments and quality assurance measures. All these measures combined made it possible to provide data users with a controlled and cleaned final data set, including a detailed documentation.

Der Kinder- und Jugendgesundheitssurvey (KiGGS): Stichprobendesign, Response und Nonresponse-Analyse

From May 2003 to May 2006, the Robert Koch Institute conducted the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). Aim of this nationwide interview and examination survey was to collect, for the first time, comprehensive and nationwide data on the health status of children and adolescents aged 0 to 17 years. Subject recruitment was carried out in two steps: first, 167 study locations (sample points) were chosen; second, subjects were selected from the official registers of residents of the local residents' registration offices. The percentage of quality-neutral drop-outs was comparatively low (5.3%). The participation rate was 66.6% and showed only little variation between age groups and sexes, but marked variation between resident aliens and Germans, between inhabitants of cities with a population of 100,000 or more and sample points with fewer inhabitants, as well as between the old West German states and the newly-formed German states (incl. Berlin). A total of 17,641 children and adolescents were surveyed, of whom 8,985 were boys and 8,656 were girls. The completeness of the data sets in relation to the modules was good. The main reasons for non-participation were failure to appear at an agreed appointment time (or cancellation of the appointment at short notice), the refusal of the child/adolescent himself, or lack of interest of the parents.

[Smoking as potential confounder in german epidemiological studies: standardization of assessment, quantification, and analysis]

Tobacco smoking is one of the most frequently examined risk factors in epidemiological studies due to the high frequency of smoking in the population and its high risk potential. This paper discusses the issue of standardization of the assessment of tobacco exposure in German epidemiological studies based on a suggestion of the working group "Epidemiological methods" of the German Society of Epidemiology (DGEpi), the German Society of Social Medicine and Prevention (DGSMP), and German Society of Medical Informatics, Biometry and Epidemiology (GMDS) together with the working group "Epidemiology in the workplace" of the DGEpi and the German Society of Occupational and Environmental Medicine (DGAUM). The main element is a short questionnaire for German adults for the assessment of tobacco smoking in epidemiological studies where smoking is a potential confounder. In addition, information on the consideration of intermittent periods of non-smoking, a very short questionnaire for medical examinations in the workplace or non-responder interviews as well as the quantification and statistical modelling of smoking are presented. A brief discussion of scientific problems and questionnaires related to the exposure to environmental tobacco smoke is given.

Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case-control studies

OBJECTIVE

To determine the risk of lung cancer associated with exposure at home to the radioactive disintegration products of naturally occurring radon gas.

DESIGN

Collaborative analysis of individual data from 13 case-control studies of residential radon and lung cancer.

SETTING

Nine European countries.

SUBJECTS

7148 cases of lung cancer and 14,208 controls.

MAIN OUTCOME MEASURES

Relative risks of lung cancer and radon gas concentrations in homes inhabited during the previous 5-34 years measured in becquerels (radon disintegrations per second) per cubic metre (Bq/m3) of household air.

RESULTS

The mean measured radon concentration in homes of people in the control group was 97 Bq/m3, with 11% measuring > 200 and 4% measuring > 400 Bq/m3. For cases of lung cancer the mean concentration was 104 Bq/m3. The risk of lung cancer increased by 8.4% (95% confidence interval 3.0% to 15.8%) per 100 Bq/m3 increase in measured radon (P = 0.0007). This corresponds to an increase of 16% (5% to 31%) per 100 Bq/m3 increase in usual radon--that is, after correction for the dilution caused by random uncertainties in measuring radon concentrations. The dose-response relation seemed to be linear with no threshold and remained significant (P = 0.04) in analyses limited to individuals from homes with measured radon < 200 Bq/m3. The proportionate excess risk did not differ significantly with study, age, sex, or smoking. In the absence of other causes of death, the absolute risks of lung cancer by age 75 years at usual radon concentrations of 0, 100, and 400 Bq/m3 would be about 0.4%, 0.5%, and 0.7%, respectively, for lifelong non-smokers, and about 25 times greater (10%, 12%, and 16%) for cigarette smokers.

CONCLUSIONS

Collectively, though not separately, these studies show appreciable hazards from residential radon, particularly for smokers and recent ex-smokers, and indicate that it is responsible for about 2% of all deaths from cancer in Europe.