Direct comparison of clinical diagnostic sensitivity of saliva from buccal swabs versus combined oro-/nasopharyngeal swabs in the detection of SARS-CoV-2 B.1.1.529 Omicron.

BACKGROUND/PURPOSE: While current guidelines recommend the use of respiratory tract specimens for the direct detection of SARS-CoV-2 infection, saliva has recently been suggested as preferred sample type for the sensitive detection of SARS-CoV-2 B.1.1.529 (Omicron). By comparing saliva collected using buccal swabs and oro-/nasopharyngeal swabs from patients hospitalized due to COVID-19, we aimed at identifying potential differences in virus detection sensitivity between these sample types. METHODS: We compare the clinical diagnostic sensitivity of paired buccal swabs and combined oro-/nasopharyngeal swabs from hospitalized, symptomatic COVID-19 patients collected at median six days after symptom onset by real-time polymerase chain reaction (PCR) and antigen test. RESULTS: Of the tested SARS-CoV-2 positive sample pairs, 55.8% were identified as SARS-CoV-2 Omicron BA.1 and 44.2% as Omicron BA.2. Real-time PCR from buccal swabs generated significantly higher quantification cycle (Cq) values compared to those from matched combined oro-/nasopharyngeal swabs and resulted in an increased number of false-negative PCR results. Reduced diagnostic sensitivity of buccal swabs by real-time PCR was observed already at day one after symptom onset. Similarly, antigen test detection rates were reduced in buccal swabs compared to combined oro-/nasopharyngeal swabs. CONCLUSION: Our results suggest reduced clinical diagnostic sensitivity of saliva collected using buccal swabs when compared to combined oro-/nasopharyngeal swabs in the detection of SARS-CoV-2 Omicron in symptomatic individuals.

Modeling the impact of the Omicron infection wave in Germany.

In November 2021, the first infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern (VOC) B.1.1.529 ('Omicron') was reported in Germany, alongside global reports of reduced vaccine efficacy (VE) against infections with this variant. The potential threat posed by its rapid spread in Germany was, at the time, difficult to predict. We developed a variant-dependent population-averaged susceptible-exposed-infected-recovered infectious-disease model that included information about variant-specific and waning VEs based on empirical data available at the time. Compared to other approaches, our method aimed for minimal structural and computational complexity and therefore enabled us to respond to changes in the situation in a more agile manner while still being able to analyze the potential influence of (non-)pharmaceutical interventions (NPIs) on the emerging crisis. Thus, the model allowed us to estimate potential courses of upcoming infection waves in Germany, focusing on the corresponding burden on intensive care units (ICUs), the efficacy of contact reduction strategies, and the success of the booster vaccine rollout campaign. We expected a large cumulative number of infections with the VOC Omicron in Germany with ICU occupancy likely remaining below capacity, nevertheless, even without additional NPIs. The projected figures were in line with the actual Omicron waves that were subsequently observed in Germany with respective peaks occurring in mid-February and mid-March. Most surprisingly, our model showed that early, strict, and short contact reductions could have led to a strong 'rebound' effect with high incidences after the end of the respective NPIs, despite a potentially successful booster campaign. The results presented here informed legislation in Germany. The methodology developed in this study might be used to estimate the impact of future waves of COVID-19 or other infectious diseases.

Safety and effectiveness of vaccines against COVID-19 in children aged 5-11 years: a systematic review and meta-analysis.

BACKGROUND: To date, more than 761 million confirmed SARS-CoV-2 infections have been recorded globally, and more than half of all children are estimated to be seropositive. Despite high SARS-CoV-2 infection incidences, the rate of severe COVID-19 in children is low. We aimed to assess the safety and efficacy or effectiveness of COVID-19 vaccines approved in the EU for children aged 5-11 years. METHODS: In this systematic review and meta-analysis, we included studies of any design identified through searching the COVID-19 L·OVE (living overview of evidence) platform up to Jan 23, 2023. We included studies with participants aged 5-11 years, with any COVID-19 vaccine approved by the European Medicines Agency-ie, mRNA vaccines BNT162b2 (Pfizer-BioNTech), BNT162b2 Bivalent (against original strain and omicron [BA.4 or BA.5]), mRNA-1273 (Moderna), or mRNA-1273.214 (against original strain and omicron BA.1). Efficacy and effectiveness outcomes were SARS-CoV-2 infection (PCR-confirmed or antigen-test confirmed), symptomatic COVID-19, hospital admission due to COVID-19, COVID-19-related mortality, multisystem inflammatory syndrome in children (MIS-C), and long-term effects of COVID-19 (long COVID or post-COVID-19 condition as defined by study investigators or per WHO definition). Safety outcomes of interest were serious adverse events, adverse events of special interest (eg, myocarditis), solicited local and systemic events, and unsolicited adverse events. We assessed risk of bias and rated the certainty of evidence (CoE) using the Grading of Recommendations Assessment, Development and Evaluation approach. This study was prospectively registered with PROSPERO, CRD42022306822. FINDINGS: Of 5272 screened records, we included 51 (1·0%) studies (n=17 [33%] in quantitative synthesis). Vaccine effectiveness after two doses against omicron infections was 41·6% (95% CI 28·1-52·6; eight non-randomised studies of interventions [NRSIs]; CoE low), 36·2% (21·5-48·2; six NRSIs; CoE low) against symptomatic COVID-19, 75·3% (68·0-81·0; six NRSIs; CoE moderate) against COVID-19-related hospitalisations, and 78% (48-90, one NRSI; CoE very low) against MIS-C. Vaccine effectiveness against COVID-19-related mortality was not estimable. Crude event rates for deaths in unvaccinated children were less than one case per 100 000 children, and no events were reported for vaccinated children (four NRSIs; CoE low). No study on vaccine effectiveness against long-term effects was identified. Vaccine effectiveness after three doses was 55% (50-60; one NRSI; CoE moderate) against omicron infections, and 61% (55-67; one NRSI; CoE moderate) against symptomatic COVID-19. No study reported vaccine efficacy or effectiveness against hospitalisation following a third dose. Safety data suggested no increased risk of serious adverse events (risk ratio [RR] 0·83 [95% CI 0·21-3·33]; two randomised controlled trials; CoE low), with approximately 0·23-1·2 events per 100 000 administered vaccines reported in real-life observations. Evidence on the risk of myocarditis was uncertain (RR 4·6 [0·1-156·1]; one NRSI; CoE low), with 0·13-1·04 observed events per 100 000 administered vaccines. The risk of solicited local reactions was 2·07 (1·80-2·39; two RCTs; CoE moderate) after one dose and 2·06 (1·70-2·49; two RCTs; CoE moderate) after two doses. The risk of solicited systemic reactions was 1·09 (1·04-1·16; two RCTs; CoE moderate) after one dose and 1·49 (1·34-1·65; two RCTs; CoE moderate) after two doses. The risk of unsolicited adverse events after two doses (RR 1·21 [1·07-1·38]; CoE moderate) was higher among mRNA-vaccinated compared with unvaccinated children. INTERPRETATION: In children aged 5-11 years, mRNA vaccines are moderately effective against infections with the omicron variant, but probably protect well against COVID-19 hospitalisations. Vaccines were reactogenic but probably safe. Findings of this systematic review can serve as a basis for public health policy and individual decision making on COVID-19 vaccination in children aged 5-11 years. FUNDING: German Federal Joint Committee.

Vaccine effectiveness against severe COVID-19 during the Omicron wave in Germany: results from the COViK study.

PURPOSE: COViK, a prospective hospital-based multicenter case-control study in Germany, aims to assess the effectiveness of COVID-19 vaccines against severe disease. Here, we report vaccine effectiveness (VE) against COVID-19-caused hospitalization and intensive care treatment during the Omicron wave. METHODS: We analyzed data from 276 cases with COVID-19 and 494 control patients recruited in 13 hospitals from 1 December 2021 to 5 September 2022. We calculated crude and confounder-adjusted VE estimates. RESULTS: 21% of cases (57/276) were not vaccinated, compared to 5% of controls (26/494; p < 0.001). Confounder-adjusted VE against COVID-19-caused hospitalization was 55.4% (95% CI: 12-78%), 81.5% (95% CI: 68-90%) and 95.6% (95%CI: 88-99%) after two, three and four vaccine doses, respectively. VE against hospitalization due to COVID-19 remained stable up to one year after three vaccine doses. CONCLUSION: Three vaccine doses remained highly effective in preventing severe disease and this protection was sustained; a fourth dose further increased protection.

Effectiveness of vaccines in preventing hospitalization due to COVID-19: A multicenter hospital-based case-control study, Germany, June 2021 to January 2022.

We included 852 patients in a prospectively recruiting multicenter matched case-control study in Germany to assess vaccine effectiveness (VE) in preventing COVID-19-associated hospitalization during the Delta-variant dominance. The two-dose VE was 89 % (95 % CI 84-93 %) overall, 79 % in patients with more than two comorbidities and 77 % in adults aged 60-75 years. A third dose increased the VE to more than 93 % in all patient-subgroups.

[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.

Impact of industry sponsorship on the quality of systematic reviews of vaccines: a cross-sectional analysis of studies published from 2016 to 2019.

BACKGROUND: Systematic reviews (SRs) provide the highest level of evidence and inform evidence-based decision making in health care. Earlier studies found association with industry to be negatively associated with methodological quality of SRs. However, this has not been investigated in SRs on vaccines. METHODS: We performed a systematic literature search using MEDLINE and EMBASE in March 2020. The results were restricted to those published between 2016 and 2019 with no language restrictions. Study characteristics were extracted by one person and checked by an experienced reviewer. The methodological quality of the SRs was assessed with the AMSTAR 2 tool by multiple reviewers after a calibration exercise was performed. A summary score for each SR was calculated. The Mann-Whitney U test and Fisher's exact test were performed to compare both groups. RESULTS: Out of 185 SRs that met all inclusion criteria, 27 SRs were industry funded. Those were matched with 30 non-industry funded SRs resulting in a total sample size of 57. The mean AMSTAR 2 summary score across all SRs was 0.49. Overall, the median AMSTAR 2 summary score was higher for the non-industry funded SRs than for the industry-funded SRs (0.62 vs. 0.36; p < .00001). Lower ratings for industry funded SRs were consistent across all but one AMSTAR 2 item, though significantly lower only for three specific items. CONCLUSION: The methodological quality of SRs in vaccination is comparable to SRs in other fields, while it is still suboptimal. We are not able to provide a satisfactory explanation why industry funded SRs had a lower methodological quality than non-industry funded SRs over recent years. Industry funding is an important indicator of methodological quality for vaccine SRs and should be carefully considered when appraising SR quality.

Facing the Omicron variant-how well do vaccines protect against mild and severe COVID-19? Third interim analysis of a living systematic review.

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant is currently the dominant variant globally. This third interim analysis of a living systematic review summarizes evidence on the effectiveness of the coronavirus disease 2019 (COVID-19) vaccine (vaccine effectiveness, VE) and duration of protection against Omicron. Methods: We systematically searched literature on COVID-19 for controlled studies, evaluating the effectiveness of COVID-19 vaccines approved in the European Union up to 14/01/2022, complemented by hand searches of websites and metasearch engines up to 11/02/2022. We considered the following comparisons: full primary immunization vs. no vaccination, booster immunization vs. no vaccination, and booster vs. full primary immunization. VE against any confirmed SARS-CoV-2 infection, symptomatic, and severe COVID-19 (i.e., COVID-19-related hospitalization, ICU admission, or death) was indicated, providing estimate ranges. Meta-analysis was not performed due to high study heterogeneity. The risk of bias was assessed with ROBINS-I, and the certainty of the evidence was evaluated using GRADE. Results: We identified 26 studies, including 430 to 2.2 million participants, which evaluated VE estimates against infections with the SARS-CoV-2 Omicron variant. VE against any confirmed SARS-CoV-2 infection ranged between 0-62% after full primary immunization and between 34-66% after a booster dose compared to no vaccination. VE range for booster vs. full primary immunization was 34-54.6%. After full primary immunization VE against symptomatic COVID-19 ranged between 6-76%. After booster immunization VE ranged between 3-84% compared to no vaccination and between 56-69% compared to full primary immunization. VE against severe COVID-19 ranged between 3-84% after full primary immunization and between 12-100% after booster immunization compared to no vaccination, and 100% (95% CI 71.4-100) compared to full primary immunization (data from only one study). VE was characterized by a moderate to strong decline within 3-6 months for SARS-CoV-2 infections and symptomatic COVID-19. Against severe COVID-19, protection remained robust for at least up to 6 months. Waning immunity was more profound after primary than booster immunization. The risk of bias was moderate to critical across studies and outcomes. GRADE certainty was very low for all outcomes. Conclusions: Under the Omicron variant, the effectiveness of EU-licensed COVID-19 vaccines in preventing any SARS-CoV-2 infection is low and only short-lasting after full primary immunization, but can be improved by booster vaccination. VE against severe COVID-19 remains high and is long-lasting, especially after receiving the booster vaccination.

Facing the Omicron variant—how well do vaccines protect against mild and severe COVID-19? Third interim analysis of a living systematic review

Background The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant is currently the dominant variant globally. This third interim analysis of a living systematic review summarizes evidence on the effectiveness of the coronavirus disease 2019 (COVID-19) vaccine (vaccine effectiveness, VE) and duration of protection against Omicron. Methods We systematically searched literature on COVID-19 for controlled studies, evaluating the effectiveness of COVID-19 vaccines approved in the European Union up to 14/01/2022, complemented by hand searches of websites and metasearch engines up to 11/02/2022. We considered the following comparisons: full primary immunization vs. no vaccination, booster immunization vs. no vaccination, and booster vs. full primary immunization. VE against any confirmed SARS-CoV-2 infection, symptomatic, and severe COVID-19 (i.e., COVID-19-related hospitalization, ICU admission, or death) was indicated, providing estimate ranges. Meta-analysis was not performed due to high study heterogeneity. The risk of bias was assessed with ROBINS-I, and the certainty of the evidence was evaluated using GRADE. Results We identified 26 studies, including 430 to 2.2 million participants, which evaluated VE estimates against infections with the SARS-CoV-2 Omicron variant. VE against any confirmed SARS-CoV-2 infection ranged between 0–62% after full primary immunization and between 34–66% after a booster dose compared to no vaccination. VE range for booster vs. full primary immunization was 34–54.6%. After full primary immunization VE against symptomatic COVID-19 ranged between 6-76%. After booster immunization VE ranged between 3-84% compared to no vaccination and between 56-69% compared to full primary immunization. VE against severe COVID-19 ranged between 3-84% after full primary immunization and between 12-100% after booster immunization compared to no vaccination, and 100% (95% CI 71.4-100) compared to full primary immunization (data from only one study). VE was characterized by a moderate to strong decline within 3–6 months for SARS-CoV-2 infections and symptomatic COVID-19. Against severe COVID-19, protection remained robust for at least up to 6 months. Waning immunity was more profound after primary than booster immunization. The risk of bias was moderate to critical across studies and outcomes. GRADE certainty was very low for all outcomes. Conclusions Under the Omicron variant, the effectiveness of EU-licensed COVID-19 vaccines in preventing any SARS-CoV-2 infection is low and only short-lasting after full primary immunization, but can be improved by booster vaccination. VE against severe COVID-19 remains high and is long-lasting, especially after receiving the booster vaccination.

Tick-Borne Encephalitis Risk Increases with Dog Ownership, Frequent Walks, and Gardening: A Case-Control Study in Germany 2018-2020.

In Germany, tick-borne encephalitis (TBE) infections mainly occur in southern regions. Despite recent increases in incidence, TBE vaccination coverage remains low, necessitating additional preventive strategies against TBE. Our case-control study in Southern Germany from 2018 to 2020 mapped knowledge/application of tick-protective strategies and identified TBE risk factors. We calculated odds ratios (OR), with 95% confidence intervals (CI). We interviewed 581 cases and 975 matched controls. Most participants recalled lifetime tick bites, mainly while walking, gardening, or hiking. However, only 45% of cases noticed ticks during exposure time; another 12% reported unpasteurized milk intake. While tick-protection knowledge was satisfactory, application lagged behind. Risk factors included dog ownership (OR = 2.45, 95% CI: 1.85-3.24), walks ≥ 4×/week (OR = 2.11, 95% CI: 1.42-3.12), gardening ≥ 4×/week (OR = 1.83, 95% CI: 1.11-3.02), and garden proximity < 250 m of forests (OR = 2.54, 95% CI: 1.82-3.56). Applying ≥2 tick-protective strategies (OR = 0.52, 95% CI: 0.40-0.68) and keeping lawns mowed (OR = 0.63, 95% CI: 0.43-0.91) were inversely associated with TBE. In 2020 (likely pandemic-related), cases reported significantly more walks than previously, potentially explaining the record high case numbers. Our findings provide guidance on targets for TBE prevention. Persons with gardens near forests, frequent outdoor activities, or dogs could particularly benefit from targeted information, including on vaccination and preventing tick bites.

Effectiveness of COVID-19 vaccines against SARS-CoV-2 infection with the Delta (B.1.617.2) variant: second interim results of a living systematic review and meta-analysis, 1 January to 25 August 2021.

The Delta variant has become the dominant strain of SARS-CoV-2. We summarised the evidence on COVID-19 vaccine effectiveness (VE) identified in 17 studies that investigated VE against different endpoints. Pooled VE was 63.1% (95% confidence interval (CI): 40.9-76.9) against asymptomatic infection, 75.7% (95% CI: 69.3-80.8) against symptomatic infection and 90.9% (95% CI: 84.5-94.7) against hospitalisation. Compared with the Alpha variant, VE against mild outcomes was reduced by 10-20%, but fully maintained against severe COVID-19.

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.

Supporting National Immunization Technical Advisory Groups in the WHO European Region in developing national COVID-19 vaccination recommendations through online communication platform.

National Immunization Technical Advisory Groups are groups of multi-disciplinary experts that provide scientific advice to policy makers to enable them to make informed immunization policy and programme decisions. NITAGs faced challengesusing their routine approach to develop recommendations for COVID-19 vaccines during the pandemic. In response, the WHORegional Office for Europe (Regional Office), with the support of theRobert Koch Institute, developedan innovative approach of a series of webinars, provision of materials, and remote technical assistance to address these challenges. Polls conducted during webinars were used to tailor future webinars and evaluate the effectiveness of these interventions. According to poll results, 76% of participants found the webinars and resources shared very useful in their work on COVID-19 vaccination.The Regional Office plans to build further upon the scope of online communication and establish a regional online platform for NITAGs to further support NITAGs and build capacity.

[COVID-19 patients in Germany: exposure risks and associated factors for hospitalization and severe disease]. / COVID-19-Patientinnen und -Patienten in Deutschland: Expositionsrisiken und assoziierte Faktoren für Hospitalisierungen und schwere Krankheitsverläufe.

The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) spread worldwide in 2020. By the end of June 2021, over 3.7 million people had been infected in Germany. The spread of the infection, however, is not evenly distributed across all parts of the population. Some groups are at a higher risk for SARS-CoV­2 infections or severe coronavirus disease 2019 (COVID-19) trajectories than others.This narrative review provides an overview of the parts of the population in Germany that are most affected by COVID-19. In addition, risk factors associated with hospitalization or severe courses of COVID-19 are identified.SARS-CoV­2 transmission may occur in various locations and settings. Professional settings, e.g., in the meat-processing industry, but also leisure activities and large public events are particularly affected. In the course of the pandemic, certain comorbidities associated with an increased risk for hospitalization or severe courses of COVID-19 have been identified. These include preexisting pulmonary, cardiovascular, and metabolic diseases. Patients with organ transplants and people with Down syndrome (trisomy 21) have the highest risk for hospitalization after SARS-CoV­2 infection.The identified settings that contribute to the spread of SARS-CoV­2 and the knowledge about vulnerable groups with a higher risk for hospitalization or severe disease trajectories form an important evidence base for the planning of prevention strategies and the fight against the pandemic.

Efficacy and effectiveness of COVID-19 vaccines against SARS-CoV-2 infection: interim results of a living systematic review, 1 January to 14 May 2021.

Evidence on COVID-19 vaccine efficacy/effectiveness (VE) in preventing asymptomatic SARS-CoV-2 infections is needed to guide public health recommendations for vaccinated people. We report interim results of a living systematic review. We identified a total of 30 studies that investigated VE against symptomatic and/or asymptomatic infection. In fully vaccinated individuals, VE against symptomatic and asymptomatic infections was 80-90% in nearly all studies. Fully vaccinated persons are less likely to become infected and contribute to transmission.