Coronavirus variant Omikron (B1.1.529) detected in Munich wastewater

Since April 2020, the Munich project team* has been analyzing samples from the Munich sewer system once and now twice a week. The samples are examined in the laboratory using RT-PCR (reverse transcription polymerase chain reaction) and genome sequencing. As infected people excrete at least fragments of the coronavirus via their excretions, the genetic material of virus variants of concern can be detected using modern molecular analyses of wastewater.

Sequencing results of the latest wastewater samples

In their latest sequencing results from today (20.12.2021), wastewater samples up to 10.12.2021 were analyzed. The samples were taken from four locations in Munich and at a wastewater treatment plant. The researchers detected traces of the coronavirus variant Omikron in five out of six samples. The wastewater samples with evidence of Omikron were taken at different locations. As the samples were analyzed retrospectively, calendar week 49 could be determined as the period for the occurrence of Omikron in the Munich population.

PD Dr. med. Andreas Wieser explains: "We were able to detect small amounts of sequences in the samples that are considered specific for the Omikron variant. This indicates that the spread of this virus variant in Munich was already greater in calendar week 49 than previously assumed. This underlines the important contribution of wastewater monitoring to the description of the infection process. Follow-up investigations are now necessary."

The sequences of strains of the delta variant (B.1.617.2) continued to dominate in the wastewater samples.

"Unfortunately, Omikron is also reaching us. Despite slightly decreasing incidence values in Bavaria, we must now continue to be cautious and prudent, because we still don't know much about the danger of the new variant. The fact is: the booster vaccination, keeping your distance, wearing a mask and avoiding unnecessary contact help to slow down Omikron. The research team's findings show us how important and valuable it is that our scientists are closely monitoring the pandemic with highly innovative tools. This means we are informed about further developments at an early stage and can draw conclusions about the incidence of infection over the coming weeks. Scientific findings are key in the fight against the pandemic. We will act on the basis of your findings and counter the pandemic decisively and effectively," emphasized Bavaria's Science Minister Bernd Sibler in light of the latest results.

Bavaria's Health Minister Klaus Holetschek also emphasized: "The wastewater tests are an important early warning system. The aim must be to contain or at least slow down the spread of Omikron. Bavaria has pulled out all the stops to delay the entry and is thus going beyond the federal regulations! The following applies in Bavaria: Travelers from virus variant areas must also be tested for the presence of an infection with the SARS-CoV-2 coronavirus by means of nucleic acid detection (PCR, PoC-PCR or other methods of nucleic acid amplification technology) upon or immediately after entry and need a corresponding test certificate. For people entering the country who are resident or staying in Bavaria, additional such tests will be ordered on day 5 and day 13 of quarantine. According to federal regulations, people entering the country from virus variant areas must go into quarantine, regardless of their vaccination status. Since Monday, this now also applies to people entering the country from the UK. I ask all people in Bavaria to adhere to the contact restrictions and avoid all unnecessary contact! Omikron must not become the secret guest at the Christmas party, so please exercise caution and prudence at Christmas too. Unfortunately, Omikron loves company, so I would ask you to get tested and, above all, vaccinated! The booster vaccination in particular offers good protection against severe cases."

In addition to the Tropical Institute at the LMU Hospital Munich under the direction of Professor Michael Hoelscher, the virology department of the Max von Pettenkofer Institute, the LMU Gene Center, the Munich Municipal Drainage Department, the Munich Fire Department, the Health Department of the City of Munich and the Infectiology Task Force of the Bavarian State Office for Health and Food Safety (LGL) are involved in the study.

Health Officer Beatrix Zurek: "The wastewater monitoring provides us with important data to better assess the infection situation in Munich. We need to take a close look, because the current development must be monitored very closely: The spread of the Omikron virus variant is becoming apparent. In a large city like Munich, the incidence of infection is often dynamic and diffuse. The wastewater early warning system is therefore a valuable seismograph and piece of the mosaic for assessing the infection situation."

Project team started wastewater monitoring at the beginning of the pandemic

The wastewater monitoring project in Munich, which began in April 2020, is one of the first and longest investigations to track the SARS-CoV-2 RNA viral load in wastewater worldwide and especially in Germany. It often takes several days between the increase in new coronavirus infections and the official reporting figures. Virus detection via wastewater is faster and more effective - this allows the dynamics of the pandemic and the spread of new variants in the population to be recognized early on. This was also confirmed by the results of the follow-up study published in the journal Science of the Total Environment in summer 2021 (see further information in the original publication).

The research is funded and supported by the Bavarian State Chancellery and the Bavarian Ministry of Science and the Arts as part of the "Prospective COVID-19 Cohort Munich" (KoCo19) study.

*Project partners:

• Lead: Tropical Institute (Department of Infectious Diseases and Tropical Medicine), LMU Hospital Munich
• Gene Center of the LMU Munich
• Max von Pettenkofer Institute for Virology, LMU
• Munich Municipal Drainage
• Center for International Health (CIH), LMU Munich Hospital
• German Center for Infection Research (DZIF), Munich site
• Munich Fire Department
• Health Department of the City of Munich
• Task Force Infectiology, Bavarian State Office for Health and Food Safety (LGL)

Funding

The study was funded by the Bavarian Ministry of Science and the Arts and the LMU Klinikum München. The study is accompanying and complementary to the KoCo19 study group (Representative SARS-CoV-2 Study in Munich, "Prospective COVID-19 Cohort Munich - KoCo19"), with the participation of: Helmholtz Munich, University of Bonn, University of Bielefeld, Federal Ministry of Education and Research (Project01KI20271) and the Bundeswehr Institute of Microbiology (Medical Biodefense Research Program) as well as the BMBF initiative "NaFoUniMedCovid19" (01KX2021), subproject B-FAST.