full report in German

The Infectious Disease Epidemiology Annual Report provides an overview and assessment of infectious disease data as reported to the Robert Koch Institute (RKI).

The ongoing COVID-19 pandemic continued to be the focus of the public health system in Germany in 2022. The three sub-variants of Omicron led to a very high transmission among the entire population for the first time in the third year of the pandemic due to their virological properties, which subsequently led to a sharp increase to over 30 million cases and over 33,000 of these cases dying related to COVID-19. In the 12th week of reporting, the highest number of transmitted cases per week since the beginning of the pandemic was reached with over 1.5 million cases.

Considering all infectious diseases subject to mandatory reporting since the introduction of the IfSG in 2001, almost twice as many cases were reported in 2022 alone as in all previous years. This enormous number of cases posed immense challenges for all public health structures, especially the local health authorities. The introduction of DEMIS for the reporting of infectious diseases therefore not only made a significant contribution in relieving the burden on health authorities, especially with regard to the reporting of SARS-CoV-2, but also made a substantial contribution in terms of maintaining and ensuring data quality, especially with regard to the timeliness of data entry at the local health authority.

In 2022, the downward trend in reported cases observed in the first two years of the pandemic was reversed for many notifiable infectious diseases and in some cases returned to the level of the period before the COVID-19 pandemic. An increase of diseases with human to human transmission such as measles, mumps and chickenpox, for example, was observed compared to the previous year. An increase in the incidence of whooping cough was recorded for the first time since 2017. In 2022, the incidence indicator of < 0.1 cases per 100,000 inhabitants proposed by the WHO to document successful measles elimination measures was not exceeded. The number of invasive Haemophilus influenzae cases also increased significantly, reaching 1,001 cases, the highest number ever recorded. The number of influenza cases stood out. While these were still exceptionally low in the previous year, an unusually early wave with high influenza activity was observed in the 2021/22 season, comparable to the 2017/18 influenza wave.

In terms of sexually transmitted and blood-borne infections, the highest number of syphilis cases ever reported was recorded with 8,305 cases. Similarly, the number of reported cases of Neisseria gonorrhoeae with reduced susceptibility to azithromycin, cefixime or ceftriaxone doubled compared to 2021. The number of new HIV diagnoses reported in Germany rose significantly in 2022, primarily due to the reporting of people who had fled to Germany from Ukraine, although the number of people originating from other countries and infected abroad who were reported as having been diagnosed for the first time in Germany also rose back to pre-pandemic levels (2018 – 2019). In this context, the significant increase in reported hepatitis B and hepatitis C cases should also be emphasised, which is due to various reasons that are discussed in detail in the corresponding chapters.

Compared to the first two years of the pandemic, an increase in the number of cases of classic travel-associated diseases such as dengue fever and Zikavirus disease was recorded. The rising trend of the last two years continued for malaria, although the number of cases remained below the pre-pandemic level.

Following a decline in case numbers for Enterobacterales and Acinetobacter spp. with reduced susceptibility to carbapenems or with evidence of a carbapenemase determinant in 2020 and 2021, the number of cases and outbreaks reported exceeded the pre-pandemic case numbers. This may be related to the care of war casualties and refugees from Ukraine.

As in previous years, Campylobacter enteritis, norovirus gastroenteritis and rotavirus gastroenteritis were among the most frequently reported gastrointestinal infectious diseases, with the number of cases of norovirus and rotavirus gastroenteritis increasing compared to the previous year, while the number of cases of Campylobacter enteritis decreased. In 2022, a renewed increase in reported cases of EHEC and salmonellosis was also recorded. The two largest salmonellosis outbreaks comprised 46 transmitted cases each and were both caused by S. Enteritidis, while other relatively large outbreaks were caused by S. Chester and S. Typhimurium.

With 171 cases, the highest number of diphtheria cases ever reported since the introduction of the IfSG in 2001 was reported, which is due in particular to the increase in cases caused by C. diphtheriae as part of an international outbreak among refugees.

In spring 2022, Mpox (formerly monkeypox) spread from person to person for the first time in an unprecedented global outbreak. In Germany, a total of 3,679 cases were reported to
the RKI in 2022, mainly affecting men who have sex with men in larger cities. After a steep increase in the number of cases in June and July, the outbreak declined steeply until September 2022, with only isolated cases being reported from October onwards. Such events demonstrate the relevance of a flexible and robust reporting system.

In the third year of the pandemic, integrated genomic surveillance (IGS) continued to play a key role in the detection of variants of SARS-CoV-2. IGS also continues to play a key role in the detection of outbreaks. In particular, cases that occur over a longer period of time can be more easily attributed to a protracted outbreak.