Results of the Cologne Corona surveillance (CoCoS) study - a prospective population-based cohort study: incidence data and potential underestimation of new SARS-CoV-2 adult infections by health authorities.

BACKGROUND: Current incidence estimates of SARS-CoV-2 in Germany rely to a large extent on case notifications. However, the large number of mild or asymptomatic infections is likely to result in underestimation. Population-based studies can provide valid estimates of the SARS-CoV-2 incidence and thus support health authorities to monitor the epidemiological situation and to initiate, maintain, strengthen or relax effective countermeasures. METHODS: This study was conducted in Cologne, Germany. Six-thousand randomly drawn Cologne residents, 18 years of age or older, were contacted by mail in March 2021. Study envelopes contained a kit for self-administered saliva sample and access details to a questionnaire on sociodemographic characteristics, previous positive SARS-CoV-2 RT-qPCR and completed COVID-19 vaccinations. Participants were again invited for a second round in June 2021, while those who declined participation were replaced by additional randomly drawn Cologne residents in order to reach a total of 6000 potential participants again. The saliva samples were sent to the laboratory by mail and tested for SARS-CoV-2 using RT-qPCR. The incidence estimates were adjusted for sensitivity and specificity of the test procedure and compared with the official numbers of new SARS-CoV-2 cases in the adult Cologne population. RESULTS: The first surveillance round in March 2021 (response rate: 34.08%, N = 2045) showed a SARS-CoV-2 seven-day incidence of 85 cases per 100,000 adult Cologne residents (95% CI: 9 to 319). In the same period, the officially registered cases were 125 per 100,000. The second surveillance round in June 2021 (response rate: 36.53%, N = 2192) showed a seven-day incidence of 27 per 100,000 adult Cologne residents (95% CI: 1 to 142), while the official figures for newly registered SARS-CoV-2 cases in the same period were 15 per 100,000. CONCLUSIONS: The incidence estimates do not indicate relevant underestimation of new SARS-CoV-2 infections based on case notification. Regular use of the surveillance method developed here may nevertheless complement the efforts of the health authorities to assess the epidemiological situation. TRIAL REGISTRATION: DRKS.de, German Clinical Trials Register (DRKS), Identifier: DRKS00024046 , Registered on 25 February 2021.

Protocol of the Cologne Corona Surveillance (CoCoS) Study- a prospective population-based cohort study.

BACKGROUND: Surveillance strategies are critical to cope with the current SARS-CoV-2 pandemic and to evaluate, as well as adjust government-imposed countermeasures. Incidence estimates are widely based on laboratory confirmed cases reported by health authorities. Prevalence and incidence data of SARS-CoV-2 is still scarce, along with demographic and behavioural factors associated with infection risk. METHODS: The Cologne Corona Surveillance Study will be conducted in the City of Cologne, which is the fourth-largest city in Germany with a population of approximately 1.1 million. Researchers will apply self-sampling surveillance to a rolling cohort of Cologne residents. Random samples of 6000 Cologne residents 18 years of age and older will be drawn from the registration office. Upon receiving the information and saliva sample kit, participants will be asked to fill out a questionnaire online or via phone, sign written informed consent, and send back written consent, as well as saliva sample. The saliva samples will be tested for SARS-CoV-2 by reverse PCR. The questionnaire will be administered to gather information about personal characteristics such as health status and risks. A second round of testing will take place 6 weeks after the first. DISCUSSION: Self-administered saliva sampling proved to be a legitimate and feasible alternative to nasopharyngeal swabs taken by health professionals. However, it is unclear whether the targeted response rate of 40% can be achieved and whether the results are representative of the population. TRIAL REGISTRATION: DRKS.de, German Clinical Trials Register (DRKS), Identifier: DRKS00024046 , Registered on 25 February 2021.

[Contact Investigation in Active Tuberculosis and Management of Latent TB Infection: 5-year Analysis at a German City Health Authority]. / Kontaktuntersuchungen bei aktiver Tuberkulose und Management latenter Tuberkulose: 5 Jahres-Analyse an einem deutschen Großstadt Gesundheitsamt.

BACKGROUND: As part of the German TB control program, health authorities conduct investigations among contacts of patients with active tuberculosis based on the infection prevention legislation, to identify potential infections among these persons. The aim of this study was to analyze retrospectively procedures of the city health authority Cologne, in cases of newly diagnosed latent TB infection (LTBI) over a 5-year period. METHODS: Data from the Cologne City Health Authority on contact investigations of TB cases between July 1st 2012 und December 31st 2016 were analyzed. In the absence of signs for active TB and a positive result of the interferon gamma release assay (QFT), LTBI was diagnosed in contact persons. Those with positive test results aged 16 and above and registered in Cologne were included. RESULTS: Out of 3859 contact persons, 430 met the inclusion criteria: in 174/430 cases chemo-preventive therapy (CPT) was recommended and 65 (35.1 %) actually took the course of CPT; in 117 cases, no records of CPT were found in the files and 22/430 persons with LTBI developed active TB within the observation period. CONCLUSION: If the full potential of LTBI treatment on the basis of the recommendations of WHO's "End TB-Strategy" is to be realized, the present study reveals the need to continuously improve documentation and management of LTBI in this setting.