Analysis of Fatality Impact and Seroprevalence Surveys in a Community Sustaining a SARS-CoV-2 Superspreading Event

There is ongoing debate on the COVID-19 infection fatality rate (IFR) and the impact of COVID-19 on overall population mortality. Here, we addressed these issues in a community in Germany with a major superspreader event analyzing deaths over time as well as auditing death certificates in the community.18 deaths that occurred within the first 6 months of the pandemic in the community had a positive test for SARS-CoV-2. Six out of 18 SARS-CoV-2+ deaths had non-COVID-19 related causes of death (COD). Individuals with confirmed infection and COVID-19 COD typically died of respiratory failure (75%) and tended to have fewer reported comorbidities (p=0.029). Duration between first confirmed infection and death was negatively associated to COVID-19 being COD (p=0.04). Repeated seroprevalence essays on an original sample of 587 individuals in three visits showed modest increases in seroprevalence over time, and substantial seroreversion (30% [27/90] (95% CI: [20.5%; 39.5%])). IFR estimates accordingly varied depending on COVID-19 death attribution and seroprevalence caveats. Careful ascertainment and audit of COVID-19 deaths are important in understanding the impact of the pandemic.

Analysis of the Dynamics, Outcome, and Prerequisites of the first German SARS-CoV-2 Superspreading Event

BackgroundThe beginning of the COVID-19 pandemic was shaped by superspreading events including large-scale outbreaks. In Germany the first SARS-CoV-2 outbreak was a superspreading event in a rural area during indoor carnival festivities in February 2020. Methods51 days after the event all known participants were asked to give blood samples, pharyngeal swabs and answer a self-administered questionnaire. Metric room coordinates for all tables, seats, and ventilation-points were assessed. FindingsWe analyzed infection rates among all 411 participants, and the risk of infection in relation to various factors including age, alcohol consumption, and ventilation system. Overall, 46% (n=186/404) of the participants had been infected. We demonstrate that the spatial distribution of infected participants was associated with proximity to the ventilation system (represented as inverse distance, with Odds Ratio OR 1.39, 95% KI [0.86; 2.25]). Interestingly, the risk of infection was highly associated with age, whereby children (OR: 0.33 [0.267; 0.414]) and young adults (age 18-25) had a lower risk of infection than older participants resulting in an average infection risk increase of 28% per 10 years age difference. Behavioral differences also impacted the risk of infection including time spent outside (OR: 0.55 [0.33; 0.91]) or smoking (OR: 0.32 [0.124; 0.81]). InterpretationOur findings underline the importance of proper indoor ventilation for events in the future. The lower susceptibility for children and young adults indicates their limited involvement in superspreading events. FundingThe government of North Rhine-Westphalia (Germany) supported the study with 65,000 Euro. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSThe scientific literature was searched for the term "superspreading event AND Covid-19 OR Sars Cov 2" and identified published papers from China, South Korea, Europe, and North America. Most researchers analyzed superspreading events within a health care setting e.g. in hospitals or nursing homes, or described the general impact of superspreading events on the global pandemic. Only a few metanalyses of transmission clusters analyzed party occasions (e.g. a nightclub in Berlin, Germany) as superspreading events. These reports describe less than 100 infections and are very limited due to missing data or reporting biases. Therefore, the ability to draw scientific conclusions is also limited. Additionally, to our knowledge, there are no studies, which investigated individual behavior, the location, and role of children during a superspreading event. The research for the study started April 2020 and was concluded in June 2021. Added value of this studyOur report analyzes the first COVID-19 superspreading event in Germany in detail, which was not only a unique setting but also included children and adults in the same room. We demonstrate that nearly half of the participants were infected with SARS-CoV-2 and that the proximity of the seating to the ventilation system was an important risk factor for infection. The data showed that low physical distance including singing and duration of attendance at this event increased the risk of infection, while regular smoking and spending the break of the event outside lowered the risk of infection. This underlines the benefit of airing to lower the amount of both droplets and aerosols. Furthermore, we found lower infection in children than adults despite being in the same room suggesting differences in infectability in children. Indeed, we observed that an additional 10 years of age is on average associated with 28% increased risk of infection. Implications of all the available evidenceTaken together, the results demonstrate the importance of the ventilation system during superspreading events. In particular children and young adults had a lower risk of infection during the event indicating that they have a limited role during this pandemic. Overall, our data demonstrate in detail age-dependent infectability as well as highlights to understand transmission dynamics in order to improve comprehensive public health preparedness measures.

The performance of the SARS-CoV-2 RT-PCR test as a tool for detecting SARS-CoV-2 infection in the population. A survey of routine laboratory RT-PCR test results from the region of Muenster, Germany

ObjectivesTo evaluate the population-based performance of the SARS-CoV-2 RT-PCR test as a tool for detecting SARS-CoV-2 infection during the pandemic in 2020. MethodsWe analysed SARS-CoV-2 RT-PCR results of 162,457 people living in Munster, Germany screened at nursing homes, testing sites, at schools, regional hospitals, and by general practitioners. All PCRs were done with the same cobas SARS-CoV-2 RT-PCR system (Roche Diagnostics). We stratified positive RT-PCR results by cycle threshold (Ct) values, periods of the national test strategy, age, sex, and symptoms. ResultsAmong 162,457 individuals, 4164 (2.6%) had a positive RT-PCR test result, defined as Ct<40. Depending on the national test strategy, higher positive rates were associated with testing predominantly symptomatic people. Children (0-9 years) and older adults (70+ years). Only 40.6% of test positives showed low Ct values < 25 (potentially infectious). The percentage of Ct values below 25 was lower among children (0-9), adolescents (10-19), and among the elderly (70+ years). ConclusionsRT-PCR testing as a tool for mass screening should not be used alone as a base for pandemic decision making including measures such as quarantine, isolation, and lockdown.

Seasonality of non-SARS, non-MERS Corona viruses and the impact of meteorological factors

BackgroundSeasonality is a characteristic of some respiratory viruses. The aim of our study was to evaluate the seasonality and the potential effects of different meteorological factors on the detection rate of the non-SARS Corona Virus detection by PCR. MethodsWe performed a retrospective analysis of 12763 respiratory tract sample results (288 positive and 12475 negative) for non-SARS, non-MERS Corona viruses (NL63, 229E, OC43, HKU1). The effect of seven single weather factors on the Corona virus detection rate was fitted in a logistic regression model with and without adjusting for other weather factors. ResultsCorona virus infections followed a seasonal pattern peaking from December to March and plunging from July to September. The seasonal effect was less pronounced in immunosuppressed patients compared to immunocompetent. Different automatic variable selection processes agreed to select the predictors temperature, relative humidity, cloud cover and precipitation as remaining predictors in the multivariable logistic regression model including all weather factors, with low ambient temperature, low relative humidity, high cloud cover and high precipitation being linked to increased Corona virus detection rates. ConclusionsCorona virus infections followed a seasonal pattern, which was more pronounced in immunocompetent patients compared to immunosuppressed. Several meteorological factors were associated with the Corona virus detection rate. However, when mutually adjusting for all weather factors, only temperature, relative humidity, precipitation and cloud cover contributed independently to predicting the Corona virus detection rate.

Subsequent waves of viral pandemics, a hint for the future course of the SARS-CoV-2 pandemic.

BackgroundIt is unknown if the SARS-CoV-2 pandemic will have a second wave. We analysed published data of five influenza pandemics (such as the Spanish Flu and the Swine Flu) and the SARS-CoV-1 pandemic to describe whether there were subsequent waves and how they differed. MethodsWe reanalysed literature and WHO reports on SARS-CoV-1 and literature on five influenza pandemics. We report frequencies of second and third waves, wave heights, wavelengths and time between subsequent waves. From this, we estimated peak-to-peak ratios to compare the wave heights, and wave-length-to-wave-length ratios to compare the wavelengths differences in days. Furthermore, we analysed the seasonality of the wave peaks and the time between the peak values of two waves. ResultsSecond waves, the Spanish Flu excluded, were usually about the same height and length as first waves and were observed in 93% of the 57 described epidemic events of influenza pandemics and in 42% of the 19 epidemic events of the SARS-CoV-1 pandemic. Third waves occurred in 54% of the 28 influenza and in 11% of the 19 SARS-CoV-1 epidemic events. Third waves, the Spanish Flu excluded, usually peaked higher than second waves with a peak-to-peak ratio of 0.5. ConclusionWhile influenza epidemics are usually accompanied by 2nd waves, this is only the case in the minority of SARS-Cov1 epidemics.