Mpox outbreak 2022: an overview of all cases reported to the Cologne Health Department.

PURPOSE: The worldwide mpox outbreak starting in May 2022 marks the occurrence of another previously atypical infectious disease in Europe. This study's objective was to present a comprehensive overview based on the gathered data and to illustrate the approach of the Cologne Health Department to contain the mpox outbreak. METHODS: In this retrospective observational study, 368 individuals reported to the Cologne Health Department as PCR-positive for mpox were included. Data were collected in structured telephone interviews and digitally processed. RESULTS: The first mpox case in Cologne was recorded on May 24, 2022. The local outbreak lasted approximately 4 months and reached its peak in July. The last reported case in Cologne occurred on September 17. Transmissions mostly occurred through sexual contacts (67.4%) or other close physical contacts (4.6%) between men, but also through fomites, in the context of events or occasionally in the work environment. In 21.5% of cases, no route of infection could be determined. The mean incubation period was 8.2 days. Clinically, mpox infections usually presented with skin and/or mucosal lesions accompanied by general symptoms. In 74.8% of cases, a prodromal stage was absent. Initially, the rash often had an unspecific appearance, but in the further clinical course, it usually passed through the typical stages. Most infections resolved spontaneously under home care. In 3.5% of cases, however, inpatient hospitalisation was required. Infected persons with a previous smallpox vaccination had 0.43 times the odds of unvaccinated persons to be affected by lesions in 3 or more body regions and 0.30 times the odds to develop lesions in all 5 body regions. Previous vaccination statistically reduced the total duration of symptoms by 2.0 days. CONCLUSIONS: The mpox outbreak 2022 in Cologne primarily affected men who have sex with men and have reported recent sexual encounters. The observed average incubation period was shorter than initially assumed. Mucosal involvement and associated symptoms occur in a relevant number of cases and can lead to more severe clinical courses. Previous smallpox vaccination was statistically significantly associated with milder courses of mpox. In the case of an unclear rash or symptoms suggesting mucosal involvement, mpox should be considered as a differential diagnosis. An equally rapid and well-orchestrated public health response are crucial for infection control.

Symptom diaries as a digital tool to detect SARS-CoV-2 infections and differentiate between prevalent variants.

The COVID-19 pandemic and the high numbers of infected individuals pose major challenges for public health departments. To overcome these challenges, the health department in Cologne has developed a software called DiKoMa. This software offers the possibility to track contact and index persons, but also provides a digital symptom diary. In this work, the question of whether these can also be used for diagnostic purposes will be investigated. Machine learning makes it possible to identify infections based on early symptom profiles and to distinguish between the predominant dominant variants. Focusing on the occurrence of the symptoms in the first week, a decision tree is trained for the differentiation between contact and index persons and the prevailing dominant variants (Wildtype, Alpha, Delta, and Omicron). The model is evaluated, using sex- and age-stratified cross-validation and validated by symptom profiles of the first 6 days. The variants achieve an AUC-ROC from 0.89 for Omicron and 0.6 for Alpha. No significant differences are observed for the results of the validation set (Alpha 0.63 and Omicron 0.87). The evaluation of symptom combinations using artificial intelligence can determine the individual risk for the presence of a COVID-19 infection, allows assignment to virus variants, and can contribute to the management of epidemics and pandemics on a national and international level. It can help to reduce the number of specific tests in times of low labor capacity and could help to early identify new virus variants.