Application of the screening method for estimating COVID-19 vaccine effectiveness using routine surveillance data: Germany's experience during the COVID-19 pandemic, July 2021 to March 2023.

The screening method represents a simple, quick, and practical tool for estimating vaccine effectiveness (VE) using routine disease surveillance and vaccine coverage data, even if these data cannot be linked. In Germany, where notification data, laboratory testing data, and vaccine coverage data cannot be linked due to strict data protection requirements, the screening method was used to assess COVID-19 VE continuously between July 2021 and March 2023. During this period, when Delta and Omicron variants circulated, VE estimates were produced in real-time for different age groups and clinical outcomes. Here we describe the country's overall positive experience using the screening method, including its strengths and limitations, and provide practical guidance regarding a few issues, such as case definition stringency, testing behaviour, and data stratification, that require careful consideration during data analysis and the interpretation of the results.

The Increase in Invasive Bacterial Infections With Respiratory Transmission in Germany, 2022/2023.

BACKGROUND: In late 2022, health care institutions in Germany reported an unusual number of severe, invasive bacterial infections in association with a high incidence of viral respiratory infections. METHODS: We analyzed routine data on invasive infections due to Haemophilus influenzae, Neisseria meningitidis, Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes (2017-2023) from a voluntary, laboratory-based surveillance system involving continuously participating facilities providing diagnostic routine data that cover approximately one-third of the German population. RESULTS: In the first quarter (Q1) of 2023, the number of invasive S. pyogenes isolates rose by 142% (n = 837 vs. mean Q1/2017-2019 = 346, 95% CI [258; 434]), while the number of H. influenzae isolates rose by 90% (n = 209 in Q1/2023 vs. mean Q1/2017-2019 = 110, 95% CI [79; 142]), compared to pre-pandemic seasonal peak values. The number of invasive S. pneumoniae isolates was high in two quarters (n = 1732 in Q4/2022 und Q1/2023). Adults aged 55 and older and children younger than 5 years were most affected by invasive H. influenzae, S. pneumoniae, and S. pyogenes infections. N. meningitidis was most commonly found in children under age 5. CONCLUSION: The reason for the marked rise in invasive bacterial infections may be an increased circulation of respiratory pathogens and elevated susceptibility in the population after relaxation of the measures taken to prevent COVID-19 infection. Coinfections with respiratory viruses may have reinforced this effect. We recommend continuous surveillance, preventive measures such as raising awareness about invasive bacterial diseases, and vaccination as recommended by the German Standing Committee on Vaccinations (STIKO).

Human papillomavirus prevalence and vaccine effectiveness in young women in Germany, 2017/2018: results from a nationwide study.

Background: Infections with human papillomaviruses (HPV) are sexually transmitted and can cause cancer. In Germany, vaccination against HPV is recommended for girls and boys aged 9-17 years. We aimed to investigate HPV DNA prevalence, genotype distribution and vaccine effectiveness (VE) in women aged 20-25 years 10 years after the introduction of HPV vaccination in Germany (2018-2019), and compared these data to an equally designed study from 2010-2012. Methods: Seventy six geographical clusters were randomly selected, followed by random selection of 61 women aged 20-25 years per cluster. Participants performed cervicovaginal self-sampling and answered questions on demographics, sexual behaviour and HPV vaccination. Samples were tested for 18 high risk and nine low risk HPV genotypes. We performed chi-square tests, Fisher's exact test, unpaired Student's t-test and proportion t-test, and calculated crude and adjusted prevalence ratios (PR) and 95% CIs. Results: Of 7,858 contacted women a total of 1,226 agreed to participate. Of these, 94 women were positive for HPV types 16 and/or 18. HPV16 prevalence was 7.0% (95% CI 5.6-8.6) and HPV18 prevalence was 0.8% (95% CI 0.4-1.5). HPV6 and HPV11 were rare with only five (0.4%; 0.1-0.9) and one (0%; 95% CI 0.0-0.5) positive tests. Seven hundred fifty-seven women (62%) had received at least one HPV vaccine dose and 348 (28%) were vaccinated as currently recommended. Confounder-adjusted VE was 46.4% (95% CI 4.2-70.1) against HPV16/18 infection and 49.1% (95% CI 8.2-71.8) against infection with at least one HPV genotype covered by the quadrivalent HPV vaccine. Compared with the 2010-2012 study results, HPV16/18 prevalence dropped from 22.5% (95% CI 19.0-26.3) to 10.3% (95% CI 7.5-13.9; p < 0.0001) in unvaccinated participants. Conclusion: Vaccine-covered HPV genotypes were rare among 20-25 years old women in Germany and decreased compared to the time point shortly after the start of the HPV vaccination program. HPV prevalence of almost all vaccine-covered genotypes was strongly reduced in vaccinated participants. A decrease of HPV16 and HPV18 was even observed in unvaccinated participants, compared to 2010-2012 data, suggesting indirect protection of unvaccinated women. Low VE against HPV16/18 and HPV6/11/16/18 in our study might be attributable to study design in combination with the endpoint selection of (mainly transient) HPV DNA positivity.

[Evaluation of the COVID-19 vaccination after broad implementation-an interim conclusion for Germany in July 2022]. / Evaluation der COVID-19-Impfung nach breiter Anwendung ­ ein Zwischenfazit für Deutschland im Juli 2022.

Vaccines against COVID-19 have been available in Germany since December 2020. At the Robert Koch Institute (RKI), the Immunization Unit is responsible for monitoring vaccination coverage and assessment of vaccine effectiveness. This article provides an overview of the respective reporting structures, vaccination databases, and epidemiological studies established by the Immunization Unit during the COVID-19 pandemic. We describe the COVID-19 Digital Vaccination Coverage Monitoring (DIM), which provides daily updates on vaccination coverage by age group. We next describe how, based on the DIM data and COVID-19 case data, the assessment of vaccine effectiveness against different clinical endpoints (hospitalization, intensive care, death) is performed. While this method is used for a preliminary estimate of vaccine efficacy, population-based nonrandomized studies are able to provide more precise and detailed estimates under "real-world" conditions. In this context, we describe the hospital-based case-control study COViK, which is being conducted in collaboration with the Paul Ehrlich Institute (PEI). We discuss strengths and limitations of the abovementioned structures and tools. Finally, we provide an outlook on future challenges that may arise during the ongoing pandemic and during the transition phase into an endemic situation.

SARS-CoV-2 outbreaks in hospitals and long-term care facilities in Germany: a national observational study.

BACKGROUND: Outbreaks of coronavirus disease (COVID-19) in hospitals and long-term care facilities (LTCFs) pose serious public health threats. We analysed how frequency and size of SARS-CoV-2 outbreaks in hospitals and LTCFs have altered since the beginning of the pandemic, in particular since the start of the vaccination campaign. METHODS: We used mandatory notification data on SARS-CoV-2 cases in Germany and stratified by outbreak cases in hospitals and LTCFs. German vaccination coverage data were analysed. We studied the association of the occurrence of SARS-CoV-2 outbreaks and outbreak cases with SARS-CoV-2 cases in Germany throughout the four pandemic waves. We built also counterfactual scenarios with the first pandemic wave as the baseline. FINDINGS: By 21 September 2021, there were 4,147,387 SARS-CoV-2 notified cases since March 2020. About 20% of these cases were reported as being related to an outbreak, with 1% of the cases in hospitals and 4% in LTCFs. The median number of outbreak cases in the different phases was smaller (≤5) in hospitals than in LTCFs (>10). In the first and second pandemic waves, we observed strong associations in both facility types between SARS-CoV-2 outbreak cases and total number of notified SARS-CoV-2 cases. However, during the third pandemic wave we observed a decline in outbreak cases in both facility types and only a weak association between outbreak cases and all cases. INTERPRETATION: The vaccination campaign and non-pharmaceutical interventions have been able to protect vulnerable risk groups in hospitals and LTCFs. FUNDING: No specific funding.

Pre-existing health conditions and severe COVID-19 outcomes: an umbrella review approach and meta-analysis of global evidence.

BACKGROUND: This study applies an umbrella review approach to summarise the global evidence on the risk of severe COVID-19 outcomes in patients with pre-existing health conditions. METHODS: Systematic reviews (SRs) were identified in PubMed, Embase/Medline and seven pre-print servers until December 11, 2020. Due to the absence of age-adjusted risk effects stratified by geographical regions, a re-analysis of the evidence was conducted. Primary studies were extracted from SRs and evaluated for inclusion in the re-analysis. Studies were included if they reported risk estimates (odds ratio (OR), hazard ratio (HR), relative risk (RR)) for hospitalisation, intensive care unit admission, intubation or death. Estimated associations were extracted from the primary studies for reported pre-existing conditions. Meta-analyses were performed stratified for each outcome by regions of the World Health Organization. The evidence certainty was assessed using GRADE. Registration number CRD42020215846. RESULTS: In total, 160 primary studies from 120 SRs contributed 464 estimates for 42 pre-existing conditions. Most studies were conducted in North America, European, and Western Pacific regions. Evidence from Africa, South/Latin America, and the Eastern Mediterranean region was scarce. No evidence was available from the South-East Asia region. Diabetes (HR range 1.2-2.0 (CI range 1.1-2.8)), obesity (OR range 1.5-1.75 (CI range 1.1-2.3)), heart failure (HR range 1.3-3.3 (CI range 0.9-8.2)), COPD (HR range 1.12-2.2 (CI range 1.1-3.2)) and dementia (HR range 1.4-7.7 (CI range 1.2-39.6)) were associated with fatal COVID-19 in different regions, although the estimates varied. Evidence from Europe and North America showed that liver cirrhosis (OR range 3.2-5.9 (CI range 0.9-27.7)) and active cancer (OR range 1.6-4.7 (CI range 0.5-14.9)) were also associated with increased risk of death. Association between HIV and undesirable COVID-19 outcomes showed regional heterogeneity, with an increased risk of death in Africa (HR 1.7 (CI 1.3-2.2)). GRADE certainty was moderate to high for most associations. CONCLUSION: Risk of undesirable COVID-19 health outcomes is consistently increased in certain patient subgroups across geographical regions, showing high variability in others. The results can be used to inform COVID-19 vaccine prioritisation or other intervention strategies.

Assessment of the Effects of Active Immunisation against Respiratory Syncytial Virus (RSV) using Decision-Analytic Models: A Systematic Review with a Focus on Vaccination Strategies, Modelling Methods and Input Data.

BACKGROUND: Several vaccine and antibody candidates are currently in development for the prevention of lower respiratory tract infections caused by the respiratory syncytial virus (RSV). METHODS: We searched MEDLINE, Embase, and SCOPUS and included model-based evaluations of RSV vaccinations. Two reviewers performed the selection, data extraction, and quality evaluation with EVIDEM. Cost-effectiveness (CE) estimates were converted to $US purchasing power parity (PPP), year 2018 values. Potential economic and epidemiological outcomes were summarised for maternal, infant, children, and elderly vaccinations. The PROSPERO identifier is CRD42019122570. RESULTS: In total, 22 model-based studies were reviewed. On average, a potential 27% reduction in RSV hospitalisations in infants was projected for maternal vaccination and 50% for direct infant immunisation. The CE of maternal vaccination was $US1766-5857 PPP 2018/disability-adjusted life-years (DALYs) for Global Alliance for Vaccines and Immunisation (Gavi)-eligible countries. For England, the maximum cost-effective price of maternal vaccination was estimated at $US81.5 PPP 2018. Infant vaccination was associated with higher CE ratios in low- and high-income settings. Vaccination of neonates born before the RSV season was the most cost effective in high-income settings. Higher values for vaccine effectiveness, duration of protection, and vaccine uptake increased the benefits. Due to indirect effects, the vaccination of school-age children and a cocooning strategy were effective alternatives to protect infants, and the vaccination of children aged < 5 years had a beneficial impact on the elderly. CONCLUSION: RSV vaccines with anticipated characteristics may reduce a sizeable proportion of the RSV burden. The results are subject to uncertainty because of the limited epidemiological and clinical data. Data on RSV incidence and hospitalisation risk for granular age strata should be prioritised to facilitate the evaluation of RSV interventions and decision making.

Invasive Haemophilus influenzae Infections in Germany After the Introduction of Routine Childhood Immunization, 2001-2016.

BACKGROUND: Haemophilus influenzae (Hi) serotype b (Hib) vaccination was introduced in Germany in 1990. This study presents a comprehensive overview on the burden of invasive Hi infections for 2001-2016, including serotype distribution and ampicillin resistance. METHODS: Nationwide data from statutory disease surveillance (2001-2016) were linked with laboratory surveillance data (2009-2016). Besides descriptive epidemiology, statistical analyses included multiple imputation to estimate secular trends. RESULTS: In 2001-2016, 4044 invasive Hi infections were reported. The mean incidence was 3.0 per million inhabitants, higher in males (3.2 vs 2.9 in females) and in the age groups <1 year (15.2) and ≥80 years (15.5). Nontypeable Hi (NTHi) caused 81% (n = 1545) of cases in 2009-2016. Of capsulated cases, 69% were serotype f and 17% serotype b. Of Hib cases eligible for vaccination, 10% (3/29) were fully vaccinated. For 2009-2016, significant increasing trends were observed for NTHi and Hif infections in the age groups <5 years and ≥60 years and for ampicillin resistance in NTHi. CONCLUSIONS: This is one of the most comprehensive Hi data analyses since the introduction of Hib vaccines. NTHi and Hif cause an increasing disease burden among elderly patients and infants. Ampicillin resistance in NTHi must be considered in the treatment of invasive Hi infections.

Evaluation of the statutory surveillance system for invasive MRSA infections in Germany, 2016-2017.

BACKGROUND: Mandatory notification of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections was introduced for laboratories in Germany in 2009. The aims were to support local health authorities (LHAs) in their mandate to prevent and control infections in hospitals and to improve population-based nationwide surveillance of healthcare associated infections. We evaluated the MRSA surveillance system to assess whether its aims were met and to identify areas for improvement. METHODS: Using the updated guidelines for evaluating public health surveillance systems by the Centers for Disease Control and Prevention we assessed the attributes simplicity, timeliness, data quality, acceptability, and usefulness. In 2016/2017 we interviewed staff in LHAs, state health authorities (SHAs), and laboratories and analyzed surveillance data of cases notified between 2009 and 2016. RESULTS: We interviewed 10% of LHAs (n = 38), 63% of SHAs (n = 10), 5 selected laboratories and analyzed information on 27,706 notified MRSA cases. LHAs reported that on receiving notifications from laboratories they contacted hospitals for clinical information, which was time-consuming and complicated as physicians were hard to reach or refused to answer questions, citing doctor-patient confidentiality. LHAs suggested reducing the amount of information collected as some clinical information was unnecessary for implementing control measures. LHAs stated that they received notifications on time, however surveillance data analysis showed some delay. Data completeness exceeded 90% for most variables, however it was only 68% and 80% for dates of disease onset and hospital admission respectively making it impossible to discriminate between hospital and community acquired infections in half of the cases. The surveillance system was well accepted by half of the interviewees. A third however stated that the benefits of the surveillance system were outweighed by the work associated with it. The majority rated the system to be useful for recognizing trends in the MRSA incidence and the ability to check up on infection control measures in hospitals. CONCLUSIONS: The surveillance system proved to be useful by fulfilling its aims. It was timely, acceptable and provided complete data for most variables. However, the system was complicated; ensuring that only relevant variables are reported could simplify the system without losing any of its usefulness.