Evolution of Corona variants in Hamburg

Evolution of Corona variants in Hamburg from 10.01.2021 to 19.03.2023

Project end of molecular surveillance of SARS-CoV-2 virus variants in Hamburg

Thursday, 20. April 2023

The Leibniz Institute of Virology (LIV) and the University Medical Center Hamburg-Eppendorf (UKE) had routinely analyzed a subset of new infections in Hamburg as part of the HHSurv project supported by the Free and Hanseatic City of Hamburg. The aim of the project was to track the spread of SARS-CoV-2 virus variants of concern in Hamburg and to detect both already known and potentially emerging variants. Now, the "Hamburg Surveillance Platform" ends after testing a total of 15,967 SARS-CoV-2 samples.

The project started in February 2021 and was initially scheduled to run for six months. At that time, the development of the infection incidence was worrying: at times, the incidence exceeded 100 new infections per 100,000 inhabitants within seven days. The utilization of intensive care beds in Hamburg hospitals was also high at this time. The vaccination campaign against COVID-19 in Germany had just begun and was still at a very early stage. Since December 2020, the VOC (variant of concern) of lineage B.1.1.7, also Alpha variant, first described in the United Kingdom with a number of mutations that apparently resulted in easier transmissibility (about 1.3 times) of the virus, spread in Germany.

The Virus Genomics Research Group with LIV's High Throughput Sequencing technology platform, in collaboration with the Institute of Medical Microbiology, Virology and Hygiene at Eppendorf University Hospital (UKE), randomly sampled up to 200 new infections per week from across the metropolitan area using PCR typing methods and also whole genome sequencing. Sequence data were analyzed using computer-assisted methods and subsequently evaluated by a joint LIV/UKE experts team in order to detect at an early stage the spread of already known but also the emergence of possible new mutations.

Development of the corona variants in Hamburg

The Alpha variant was detected in Hamburg from the end of 2020 and ousted the Sars-CoV-2 initial form within 4 months. From the end of May 2021, the Delta variant, first described in India, arrived in Germany and displaced all other variants within 2 months. Due to its increased transmissibility and the escape mutation S:L452R, it was able to escape the immune response and spread to Hamburg when about 50% of the population was already immunized. In late November 2021, Omikron variant-BA.1, first detected in South Africa, arrived in Hamburg and displaced Delta within a month. Omikron, unlike its precursors, is characterized by an exceptionally high number of mutations, including escape mutations, and shows an increased ability to evade the immune response. Since about the middle of last year, different Omikron sublines have emerged in parallel; it does not remain with one dominant variant.

"Now the situation is different from when the project started: 80% of Hamburgers are immunized (as of April 2023), and Corona has entered the endemic state. Thus, despite the continued dynamic development of Corona variants, it is no longer necessary to investigate the occurrence of different variants in Hamburg," explains Prof. Adam Grundhoff, head of the Virus Genomics research group.

Scientific contact persons:

Prof. Adam Grundhoff, LIV
Phone: 040/48051-275

Prof. Nicole Fischer, UKE
Phone: 040/7410-55171

To the press release of the project start on 16.02.2021