Protection From COVID-19

Bacterial contamination potential of personal protective equipment itself in dental aerosol-producing treatments

Personal protective equipment (PPE) has long been a high priority in dental aerosol-producing treatments. Since COVID-19 pandemic, its importance has increased yet again. While importance of PPE in preventing transmission and thus possible infection of pathogens is well known, contamination potential of PPE after treatment itself is less investigated. This review aims to give an overview of the current literature and contamination potential (viral, blood, bacterial) of components of protective equipment itself. The literature search was performed using the Medline database; furthermore, a hand search was conducted. Last search took place on 23 November 2022. Two categories of hygiene-related keywords were formed (category A: mask, face shield, goggles, eyewear, personal protective equipment; category B: contamination, aerosol). Each keyword from one category was combined with all keywords from the other one. In addition, the keyword "dental" was always added. First, a title and abstract screening was performed. Afterward, a full-text analysis was followed for the included studies. A total of 648 search hits were found in the Medline database. 47 were included after title and abstract screening. 22 studies were excluded after full-text analysis, 25 studies were included. The hand search resulted in 4 studies that were included. Bacterial contamination of PPE after treatment has been adequately studied, contamination with blood less. Microorganisms mainly originate from the oral and cutaneous flora; however, a transmission of potential pathogens like Staphylococcus aureus or Escherichia coli was also described. Studies showing transmission pathways starting from PPE and its various components are lacking. No measures have yet been described that fully protect the protective equipment from contamination. There is growing awareness that PPE itself can be a source of pathogen transmission, and thus possible infection. Therefore, not only wearing of protective clothing, but also conscious handling of it is crucial for transmission and possible infection prevention. However, studies showing transmission pathways starting from PPE and its various components are lacking. Several studies have investigated what measures can be taken to protect the protective equipment itself. So far, none of the methods evaluated can prevent contamination of PPE.

Characteristics associated with attitudes and behaviors towards mask wearing during the COVID-19 pandemic: The Trojan Pandemic Response Initiative

BACKGROUND

Attitudes and behaviors towards mask wearing may influence the ability to reduce transmission of COVID-19 and other diseases.

METHODS

University students, staff, and faculty (N = 9653) responded to an email invitation to complete electronic surveys (November 2021 and April 2022). Surveys included 19 items measuring attitudes and behaviors towards mask wearing from the Understanding America Study. Linear mixed models including variables for sex, age group, division, race and ethnicity, political affiliation, and history of COVID-19, were used to estimate the mean difference of the mean score for attitudes and behavior between Time 1 (November 2021) and Time 2 (April 2022).

RESULTS

Participants were mostly female (62.1%), students (70.6%), White (39.5%) and Asian (34.7%). More than half identified their political affiliation as Democrat (65.5%). Characteristic variable-by-time interactions for difference in mean mask attitude scores difference were significant at Time 1 (T1) and Time 2 (T2) between Black and White participants (B = 0.18 (0.05), 95% CI: 0.07, 0.28, p = 0.001), Asian and White participants (B = 0.07 (0.02), 95% CI: 0.03-0.12, p = 0.001), participants with self-reported history of COVID-19 and no history of COVID-19 (B= -0.13 (0.02), 95% CI: -0.07, -0.18, p < 0.0001), females and males (B = 0.07 (0.02), 95% CI: 0.03, 0.11, p = 0.001), Republicans and Democrats (B= -0.18 (0.04), 95%CI: -0.26, -0.10, p < 0.0001) and Independents and Democrats (B= -0.10 (0.03), 95%CI: -0.15, -0.05, p < 0.0001). Mean difference in mean scores for mask behaviors at Time and Time 2 were significant between participants with COVID-19 and participants who did not have COVID-19 (B= -0.12 (0.04), 95% CI: -0.19, -0.04, p = 0.004), students compared to faculty and staff (B=-0.22 (0.05), -0.32, -0.12, p < 0.0001), between Republicans and Democrats (B-= -0.16 (0.07), 95% CI: -0.28, -0.03, p = 0.020, and between Independents and Democrats (B=-0.08 (0.04), 95% CI: -0.16, -0.002, p = 0.04).

CONCLUSION

Race and ethnicity, political affiliation, and division may affect attitudes and behaviors in mask wearing. Further investigation into how characteristics influence public health measures such as mask wearing is needed to contain the spread of the COVID-19 virus, other infectious diseases, and future pandemics.

Perceived Effectiveness of COVID-19 Preventive Practices and Behavioral Intention: Survey of a Representative Adult Sample in the United States

BACKGROUND

Using existing models of behavioral health promotion, specifically the Extended Parallel Process Model, previous research has identified factors that may impact engagement in preventive health behaviors during the COVID-19 pandemic such as perceived threat, perceived susceptibility to the threat, perceived severity, and perceived efficacy.

OBJECTIVE

This study aims to examine the role of perceived effectiveness of COVID-19 preventive behaviors, perceived susceptibility, perceived threat, and perceived severity of COVID-19 in participants' intentions to engage in Centers for Disease Control (CDC)-recommended individual health behaviors in the first year of the pandemic.

METHODS

In October 2020, a representative sample of 506 US adults completed a web-based survey through the RAND American Life Panel.

RESULTS

The study primarily found that participants who perceived that CDC-recommended health practices were effective had stronger intentions to engage in those practices. The second strongest correlate was participants' perceived severity of COVID-19 across the United States. Perceived effectiveness of recommended practices accounted for the largest variance in behavioral intention. However, analysis of individual behaviors indicated a mismatch in the behaviors perceived to be the most effective (avoiding sick people and mask-wearing) and those participants indicated intention to engage in (throwing away used tissues, avoiding sick people, and coughing into their elbows) in the next 30 days.

CONCLUSIONS

The authors recommend tailoring public health messaging to address the perceived threat of COVID-19 and self-efficacy. Thus, health promotion efforts should emphasize the effectiveness of CDC-recommended practices while highlighting the pandemic's severity. Additionally, rebuilding trust in public health messaging and messengers is necessary to increase perceived self-efficacy. As the COVID-19 pandemic continues, health messaging must continue to promote and build trust in CDC-recommended health practices and educate regarding the efficacy of vaccination and other preventive behaviors.

Impact of face masks on the 6-minute walk distance in pulmonary hypertension patients during the COVID-19 pandemic: a prospective, randomised cross-over study

In patients with pulmonary hypertension (PH) or with other pulmonary or cardiac diseases, the 6-minute walking test – accompanied by the Borg dyspnea score – is frequently utilised as a semi-quantitative measure of exercise capacity [1]. The 6-minute walking distance (6 MWD) also serves as primary or key secondary endpoint in numerous clinical trials assessing the efficacy of pharmacotherapies in various forms of PH [2, 3]. Furthermore, the 6MWD is among the key non-invasive measures of multi-modal risk assessment in pulmonary arterial hypertension (PAH) [4–6]. In this context, cut-off values of 440 m and 165 m have been validated to indicate low, intermediate and high mortality risk, respectively, in the 3-strata model proposed by the current ESC/ERS guidelines [1], with an additional cut-off of 320 m to discriminate between intermediate-high and intermediate-low risk in the recently introduced 4-strata approach [7, 8].

Investigating the effect of multimedia education based on the health belief model in preventing COVID-19 in pregnant women

BACKGROUND

Pregnant women are considered one of the high-risk groups during the COVID-19 pandemic, so paying attention to preventive behaviors among them is highly important. This study aimed to examine the effect of multimedia education based on the Health Belief Model (HBM) in preventing COVID-19 among pregnant women.

METHODS

This quasi-experimental intervention study was conducted on 120 pregnant women referring to Comprehensive Health Services Centers affiliated with East and West health centres of Ahvaz city, Iran, in 2021. Participants were divided into two control (n = 60) and intervention (n = 60) groups. A researcher-made questionnaire was used for data collection. The intervention group was given the required educational content using social networks virtually and multimedia in 12 sessions. Both groups were reinvestigated after two months. Data were analyzed using SPSS software version 24, independent t-test and paired t-test tests.

RESULTS

The mean age and mean gestational age of participants were estimated at 28 years old and 18 weeks, respectively. Before the educational intervention, there was no significant difference in mean constructs of HBM. In contrast, the mean of all constructs increased significantly in the intervention group after intervention. The greatest change was related to the constructs of self-efficacy and perceived susceptibility, and the lowest change was related to the perceived barriers construct.

CONCLUSION

Our findings suggest multimedia education using the HBM to COVID-19 preventive behaviors among pregnant women can benefit behavior change.

The Difference in Electromyographic Activity While Wearing a Medical Mask in Women with and without Temporomandibular Disorders

Wearing a medical mask influences resting activity of the temporalis anterior and masseter muscles in healthy young women. However, no studies link medical mask-wearing with masticatory muscle activity in patients with temporomandibular disorders (TMDs). Therefore, this study aims to compare electromyographic patterns while wearing a medical mask between women with and without temporomandibular disorders. Based on the Research Diagnostic Criteria for Temporomandibular Disorders, 115 adult women qualified for the study. Participants were divided into the following two groups: diagnosed TMDs (n = 55; mean age: 23.5 ± 2.3 years) and healthy women (n = 60; mean age: 23.7 ± 2.6 years). Examinations of the resting and functional electromyographic activity of the temporalis anterior (TA), superficial masseter (MM), anterior bellies of the digastric muscle (DA), and the middle part of the sternocleidomastoid muscle (SCM) were carried out using the BioEMG III™. Both groups showed statistically significant decreases in resting masticatory muscle activity during medical mask examination compared to no mask measurement. The significant differences in no mask measurement between both groups were noted regarding resting masticatory activity, clenching in the intercuspal position, and clenching on dental cotton rollers. During medical mask examination, women with TMDs showed differences in resting masticatory activity and clenching on dental cotton rollers compared to the healthy group. In all analyzed variables, both groups showed similar electromyographic patterns in the maximum mouth opening measurement during medical mask and no mask examination. A medical mask influences the resting bioelectric activity of the masticatory muscles in women with temporomandibular disorders and healthy women. We observed differences and some similarities in resting and functional electromyographic patterns within masticatory and neck muscles in both groups during medical mask and no mask examination.

Effects of Wearing FFP2 Masks on SARS-CoV-2 Infection Rates in Classrooms

In this retrospective cohort study involving 614 secondary school students, the likelihood of becoming infected with SARS-CoV-2 in schools with different focus (sports focus vs. general branch; the only difference in the sports focus school was that PE was allowed at all times without restrictions) and different prevailing restrictions were compared. A significantly higher likelihood of infection with SARS-CoV-2 was found in sports classes during the period with a strict FFP-2 mask requirement compared to general branch classes (for Delta from November 2021 to December 2021, and for Omicron from January 2022 to February 2022). The higher likelihood of infection was observed both during the Delta and the Omicron wave. After the relaxation of the mitigation measures, however, students in general branch classes showed a clear "catch-up" of infections, leading to a higher incidence of infections during this phase. By the end of the observation period (30 April 2022), only a small difference in cumulative SARS-CoV-2 infection rates (p = 0.037, φ = 0.09) was detected between classes with a sports focus and those without a sports focus. The results suggest that SARS-CoV-2 transmission can be reduced in school classes by mandatory FFP-2 mask use. In many cases, however, infection appears to be postponed rather than avoided.

Compliance with Barrier Gestures during COVID-19 Pandemic as a Function of the Context: A Longitudinal Observational Survey at the University of Liège

During the COVID-19 pandemic, barrier gestures such as mask wearing, physical distancing, greetings without contact, one-way circulation flow, and hand sanitization were major strategies to prevent the spread of SARS-CoV-2, but they were only useful if consistently applied. This survey was a follow-up of the first survey performed in 2020 at the University of Liège. We aim to evaluate the compliance with these gestures on campuses and examine differences in the extent of the compliance observed in different educational activities and contexts. During 3.5 months, the counting of compliant and non-compliant behaviors was performed each week in randomly selected rooms. Using data collected during both surveys (2020 and 2021), binomial negative regression models of compliance depending on periods (teaching periods and exam sessions), type of rooms, and campuses were conducted to evaluate prevalence ratios of compliance. The percentage of compliance in this second survey was the highest for mask wearing and physical distancing during educational activities (90% and 88%, respectively) and lowest for physical distancing outside educational activities and hand sanitization (45% and 52%, respectively). Multivariate analyses revealed that the compliance with most gestures was significantly higher in teaching rooms than in hallways and restaurants and during exam sessions. The compliance with physical distancing was significantly higher (from 66%) in auditoriums, where students had to remain seated, than during practical works that allowed or required free movement. Therefore, the compliance with barrier gestures was associated with contextual settings, which should be considered when communicating and managing barrier gestures. Further studies should specify and confirm the determining contextual characteristics regarding the compliance with barrier gestures in times of pandemic.

How Middle and High School Students Wear Their Face Masks in Classrooms and School Buildings

In addition to other mitigation measures, face masks have been used in schools worldwide as a precondition for allowing school attendance during the COVID-19 pandemic. The quality and habits of mask wearing have, however, not been evaluated thus far, leaving uncertainty about the efficacy of this measure. It was the aim of this study to assess the accuracy of face mask wearing by children and adolescents in different school situations. In May and June 2022, students of two selected Austrian schools were asked to provide information about the different variations in wearing a face mask in different situations at school (in classrooms with or without the presence of a teacher, and in school buildings outside classrooms without the presence of a teacher). Strongly divergent results were identified for the amount of time in which face masks were worn correctly in the three different situations (p < 0.001, eta = 0.29). In the presence of a teacher, masks were worn correctly 63.7% of the time, while this percentage decreased to 31.9% when no teacher was present (p < 0.001). These results suggest the limited efficacy of mandatory face masks in schools. Should this measure become necessary again in the future due to the pandemic situation and highly pathogenic variants, special efforts are necessary in order to improve the quality of face mask wearing by school children.

A Simulation-Based Cost-Effectiveness Analysis of Severe Acute Respiratory Syndrome Coronavirus 2 Infection Prevention Strategies for Visitors of Healthcare Institutions

OBJECTIVES

The aim is to quantitatively evaluate different infection prevention strategies in the context of hospital visitor management during pandemics and to provide a decision support system for strategic and operational decisions based on this evaluation.

METHODS

A simulation-based cost-effectiveness analysis is applied to the data of a university hospital in Southern Germany and published COVID-19 research. The performance of different hospital visitor management strategies is evaluated by several decision-theoretic methods with varying objective functions.

RESULTS

Appropriate visitor restrictions and infection prevention measures can reduce additional infections and costs caused by visitors of healthcare institutions by >90%. The risk of transmission of severe acute respiratory syndrome coronavirus 2 by visitors of terminal care (ie, palliative care) patients can be reduced almost to 0 if appropriate infection prevention measures are implemented. Antigen tests do not seem to be beneficial from both a cost and an effectiveness perspective.

CONCLUSIONS

Hospital visitor management is crucial and effectively prevents infections while maintaining cost-effectiveness. For terminal care patients, visitor restrictions can be omitted if appropriate infection prevention measures are taken. Antigen testing plays a subordinate role, except in the case of a pure focus on additional infections caused by visitors of healthcare institutions. We provide decision support to authorities and hospital visitor managers to identify appropriate visitor restriction and infection prevention strategies for specific local conditions, incidence rates, and objectives.

Advances in the Prophylaxis of Respiratory Infections by the Nasal and the Oromucosal Route: Relevance to the Fight with the SARS-CoV-2 Pandemic

In this time of COVID-19 pandemic, the strategies for prevention of the infection are a primary concern. Looking more globally on the subject and acknowledging the high degree of misuse of protective face masks from the population, we focused this review on alternative pharmaceutical developments eligible for self-defense against respiratory infections. In particular, the attention herein is directed to the nasal and oromucosal formulations intended to boost the local immunity, neutralize or mechanically "trap" the pathogens at the site of entry (nose or mouth). The current work presents a critical review of the contemporary methods of immune- and chemoprophylaxis and their suitability and applicability in topical mucosal dosage forms for SARS-CoV-2 prophylaxis.

Accessibility to Non-COVID Health Services in the World During the COVID-19 Pandemic: Review

Background: COVID-19 pandemic caused by SARS-CoV2 has seriously impacted the global economy. Medical facilities around the world were not prepared for the enormous challenges posed by the growing number of patients each day, the shortage of personal protective equipment, and insufficient numbers of medical staff. Governments have tried to counteract the impact of the pandemic, but the measures taken have not always been sufficient to maintain access to and quality of health services at the same level as before the pandemic. The disruption of health services has resulted in more and more research reports from different parts of the world on the accessibility of health services during the COVID-19 pandemic. Methodology: This review article presents 21 selected scientific studies on access to health services in different regions of the world. Articles were found in PubMed, GoogleScholar, Medline, and ScienceDirect databases, then grouped, and significant data were extracted from each article. The results were summarized in a table. Results: The range of limited health services included a variety of specialties, including primary care, psychiatry, orthopedics, cardiology, neurosurgery, and more. Methods used in the studies were based on retrospective analysis or on the subjective assessment of patients in the form of a questionnaire or interview. Most authors claimed a decrease in accessibility to health services during the COVID-19 pandemic compared to the pre-pandemic period, including a decrease in planned surgeries, doctor appointments, patient admission to hospital or ER, and access to medicines. Additionally, some authors observed an increase in the mortality rate. One of the few medical services that have expanded rapidly during the pandemic was online appointments. Conclusions: The COVID-19 pandemic has most certainly affected the accessibility of health services worldwide. Lessons should be learned to prevent inaccessibility to medical services, especially as experts predict another wave of COVID-19 cases.

Impact of Changes in Infection Control Measures on the Dynamics of COVID-19 Infections in Schools and Pre-schools

Introduction: With the increased emergence of SARS-CoV-2 variants, the impact on schools and preschools remains a matter of debate. To ensure that schools and preschools are kept open safely, the identification of factors influencing the extent of outbreaks is of importance. Aim: To monitor dynamics of COVID-19 infections in schools and preschools and identify factors influencing the extent of outbreaks. Methods: In this prospective observational study we analyzed routine surveillance data of Mecklenburg-Western Pomerania, Germany, from calendar week (CW) 32, 2020 to CW19, 2021 regarding SARS-CoV-2 infection events in schools and preschools considering changes in infection control measures over time. A multivariate linear regression model was fitted to evaluate factors influencing the number of students, teachers and staff tested positive following index cases in schools and preschools. Due to an existing multicollinearity in the common multivariate regression model between the variables "face mask obligation for children" and "face mask obligation for adults", two further separate regression models were set up (Multivariate Model Adults and Multivariate Model Children). Results: We observed a significant increase in secondary cases in preschools in the first quarter of 2021 (CW8 to CW15, 2021), and simultaneously a decrease in secondary cases in schools. In multivariate regression analysis, the strongest predictor of the extent of the outbreaks was the teacher/ caregiver mask obligation (B = -1.9; 95% CI: -2.9 to -1.0; p < 0.001). Furthermore, adult index cases (adult only or child+adult combinations) increased the likelihood of secondary cases (B = 1.3; 95% CI: 0.9 to 1.8; p < 0.001). The face mask obligation for children also showed a significant reduction in the number of secondary cases (B = -0.6; 95% CI: -0.9 to -0.2; p = 0.004. Conclusion: The present study indicates that outbreak events at schools and preschools are effectively contained by an obligation for adults and children to wear face masks.

Spreading of Infections on Network Models: Percolation Clusters and Random Trees

We discuss network models as a general and suitable framework for describing the spreading of an infectious disease within a population. We discuss two types of finite random structures as building blocks of the network, one based on percolation concepts and the second one on random tree structures. We study, as is done for the SIR model, the time evolution of the number of susceptible (S), infected (I) and recovered (R) individuals, in the presence of a spreading infectious disease, by incorporating a healing mechanism for infecteds. In addition, we discuss in detail the implementation of lockdowns and how to simulate them. For percolation clusters, we present numerical results based on site percolation on a square lattice, while for random trees we derive new analytical results, which are illustrated in detail with a few examples. It is argued that such hierarchical networks can complement the well-known SIR model in most circumstances. We illustrate these ideas by revisiting USA COVID-19 data.

Face mask uptake in the absence of mandates during the COVID-19 pandemic: a qualitative interview study with Swiss residents

Background

In the COVID-19 pandemic, Switzerland introduced broad nationwide face mask mandates only by October 2020, later than other Western European countries. This study aims to assess the underlying values and considerations of individuals to wear face masks in the absence of face mask mandates in the COVID-19 pandemic in German-speaking Switzerland.

Methods

As part of the “Solidarity in times of a pandemic” (SolPan) research commons, we interviewed 31 participants living in the German-speaking part of Switzerland in April 2020 and 25 of them again in October 2020. Qualitative inductive thematic analysis was applied for data analysis and interpretation. Public health ethics principles guided the interpretation and organization of findings.

Results

Five themes were identified: Trust and governmental policy; perceived benefits of mask-wearing; perceived risks of mask-wearing; social exclusion and prejudice; and decision-making in the absence of mandates. In light of increasing infection rates in October 2020, many participants started to consider the benefits higher than the risks and were willing to accept face mask mandates in that context, despite earlier reservations.

Conclusions

The absence of face mask mandates underline individual autonomy but may also suppress personal responsibility due to social influence. Face masks are only temporarily acceptable in liberal Western societies and face mask mandates should be enforced only when epidemiologically necessary.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12215-4.

[Impact of wearing face masks in public to prevent infectious diseases on the psychosocial development in children and adolescents: a systematic review]

Hintergrund

Zur Prävention tröpfchenübertragener Infektionskrankheiten wird das Tragen einer Maske im öffentlichen Raum unter bestimmten Bedingungen empfohlen.

Ziel der Arbeit

Ziel war, über eine sensitive Literatursuche möglichst alle deutsch- und englischsprachigen Forschungsergebnisse aus begutachteten Fachzeitschriftenartikeln zu den Auswirkungen des Masketragens zur Prävention von Infektionen auf die psychosoziale Entwicklung von Kindern und Jugendlichen zusammenzutragen.

Methoden

Es wurde ein systematischer Review unter Berücksichtigung verschiedener Studiendesigns durchgeführt (Suchzeitraum bis einschließlich 12.07.2021). Das Verzerrungsrisiko der Studien wurde mit einem Risk-of-Bias-Verfahren ermittelt. Es fand eine deskriptiv-narrative Ergebnissynthese statt.

Ergebnisse

Es wurden 13 Studien eingeschlossen, wobei das Gesamtverzerrungsrisiko in allen Primärstudien als hoch eingeschätzt wurde. Es gibt Hinweise aus Befragungsstudien, dass die Fähigkeit zum Lesen der Mimik von Kindern/Jugendlichen und/oder ihren Betreuer:innen im (Vor‑)Schulsetting durch das Masketragen als beeinträchtigt erlebt wird, die durch mehrere Experimentalstudien bestätigt wurden. 2 Studien berichteten über psychische Symptome wie Ängste oder Stresserleben sowie Konzentrations- und Lernschwierigkeiten durch das Masketragen während der COVID-19-Pandemie. Eine Studie während der SARS-Pandemie 2002/2003 untersuchte mündliche Prüfungsleistungen in Englisch als Fremdsprache und zeigte keinen Unterschied zwischen den Bedingungen „Maske“ versus „keine Maske“.

Diskussion

Zu den Auswirkungen des Masketragens auf verschiedene Entwicklungsbereiche von Kindern und Jugendlichen lassen sich basierend auf der unzureichenden Studienlage nur wenige Erkenntnisse ableiten. Es fehlen Forschungsdaten zu den Folgen für die Endpunkte psychische Entwicklung, Sprachentwicklung, sozioemotionale Entwicklung, soziales Verhalten, Schulerfolg und Teilhabe. Weitere qualitative Studien und epidemiologische Studien sind unbedingt nötig.

Zusatzmaterial online

Zusätzliche Informationen sind in der Online-Version dieses Artikels (10.1007/s00103-021-03443-5) enthalten.

Sensitivity analysis of SARS-CoV-2 aerosol exposure

As vaccination campaigns are in progress in most countries, hopes to win back more normality are rising. However, the exact path from a pandemic to an endemic virus remains uncertain. While in the pre-vaccination phase many critical indoor situations were avoided by strict control measures, for the transition phase a certain mitigation of the effect of indoor situations seems advisable. To better understand the mechanisms of indoor airborne transmissions, we present a new time-discrete model to calculate the level of exposure towards infectious SARS-CoV-2 aerosol and carry out a sensitivity analysis for the level of SARS-CoV-2 aerosol exposure in indoor settings. Time limitations and the use of any kind of masks were found to be strong mitigation measures, while how far the effort for a strict use of professional face pieces instead of simple masks can be justified by the additional reduction of the exposure dose remains unclear. Very good ventilation of indoor spaces is mandatory. The definition of sufficient ventilation in regard to airborne SARS-CoV-2 transmission follows other rules than the standards in ventilation design. This means that especially smaller rooms most likely require a significantly greater fresh air supply than usual. Further research on 50% group models in schools is suggested. The benefits of a model in which the students come to school every day, but for a limited time, should be investigated. In terms of window ventilation, it has been found that many short opening periods are not only thermally beneficial, they also reduce the exposure dose. The fresh air supply is driven by the temperature gradient and wind speed. However, the sensitivity towards these parameters is not very high and in times of low wind and temperature gradients, there are no arguments against keep windows open in order to make up for the reduced air flow rate. Long total opening periods and large window surfaces will strongly reduce the exposure. Additionally, the results underline the expectable fact that exposure doses will increase when hygiene and control measures are reduced. It seems advisable to investigate what this means for the infection rate and the fatality of infections in populations with partial immunity. Very basic considerations suggest that the value of aerosol reduction measures may be reduced with very infectious variants such as delta.

[COVID-19 outbreak investigation in a geriatric palliative hospital]

BACKGROUND

During the second COVID-19 wave, a large COVID-19 outbreak happened at a 90-bed geriatric palliative care hospital in December 2020, whereby 32 % of the healthcare personnel (HCP) and 29 patients became infected within 23 days and 13 patients died. The bed occupancy rate dropped to 20 %. Drastically enhanced hygiene measures directly after outbreak detection could stop further nosocomial infections among patients but were less effective among HCP.

OBJECTIVE

Outbreak investigation and detection of risk factors for infection in HCP.

MATERIAL AND METHODS

Anonymous online survey among HCP from January and February 2021 investigating potential risk factors for PCR positive infections (poorly fitting FFP2 masks, close contacts with positive patients, team meetings with positive HCP).

RESULTS

Of 184 HCP, 96 completed the survey (52.2 %), including 38 who became infected. Of the HCP 8 remained asymptomatic/oligosymptomatic, 30 HCP became ill for a median of 10 days and in 2 continuously. Factors associated with an infection were close contacts with positive patients in a time-dependent manner despite wearing an FFP2 mask (OR 6.0; 95 % CI 1.6-22). Out of 88 HCP 55 described poorly fitting FFP2 masks. An infection was mostly attributed to a longer contact with positive, sometimes restless patients. The overall exhausting working situation was repeatedly mentioned.

CONCLUSION

A COVID outbreak within the care-intense geriatric context is challenging to control especially among HCP. Longer patient contacts and limited compliance by patients counteracts strict hygiene measures. Vulnerability of HCP and patients requires additional preventive interventions by rapidly effective vaccinations and has to be a priority for health policy.

Estimating the impact of control measures to prevent outbreaks of COVID-19 associated with air travel into a COVID-19-free country

We aimed to estimate the risk of COVID-19 outbreaks associated with air travel to a COVID-19-free country [New Zealand (NZ)]. A stochastic version of the SEIR model CovidSIM v1.1, designed specifically for COVID-19 was utilised. We first considered historical data for Australia before it eliminated COVID-19 (equivalent to an outbreak generating 74 new cases/day) and one flight per day to NZ with no interventions in place. This gave a median time to an outbreak of 0.2 years (95% range of simulation results: 3 days to 1.1 years) or a mean of 110 flights per outbreak. However, the combined use of a pre-flight PCR test of saliva, three subsequent PCR tests (on days 1, 3 and 12 in NZ), and various other interventions (mask use and contact tracing) reduced this risk to one outbreak after a median of 1.5 years (20 days to 8.1 years). A pre-flight test plus 14 days quarantine was an even more effective strategy (4.9 years; 2,594 flights). For a much lower prevalence (representing only two new community cases per week in the whole of Australia), the annual risk of an outbreak with no interventions was 1.2% and had a median time to an outbreak of 56 years. In contrast the risks associated with travellers from Japan and the United States was very much higher and would need quarantine or other restrictions. Collectively, these results suggest that multi-layered interventions can markedly reduce the risk of importing the pandemic virus via air travel into a COVID-19-free nation. For some low-risk source countries, there is the potential to replace 14-day quarantine with alternative interventions. However, all approaches require public and policy deliberation about acceptable risks, and continuous careful management and evaluation.