Monkeypox - What the HZI experts say

Since mid-May 2022, several countries where monkeypox is not endemic have reported an accumulation of infections with the monkeypox virus. The first cases have also been diagnosed in Germany. Researchers at the Helmholtz Centre for Infection Research (HZI) are contributing their expertise to assessing the current situation and informing the public.

Monkeypox virus (MPXV) is related to the eradicated smallpox virus. Despite the name, monkeys are not the natural reservoir of the virus. Instead, rodents are probably the reservoir from which monkeys can also contract the virus. It is currently unknown via which animals the virus has jumped to humans in the current cases.

Prof Fabian Leendertz, founding director of the Helmholtz Institute for One Health (HIOH) in Greifswald and head of the department "Ecology and Emergence of Zoonoses", studies the interface between animal health, the environment and human health. The HIOH is a site of the HZI, which is being established together with the University of Greifswald, the Greifswald University Medicine and the Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health (FLI) as local founding partners. To Science Media Center Germany, he assesses the current situation as follows:

I would already call this an epidemic, but it is very unlikely that this epidemic will last long. The cases via contact tracing can be well contained and there are also drugs and effective vaccines that can be used if necessary.

Prof Fabian Leendertz, Founding Director of the Helmholtz Institute for One Health

However, good epidemiological data are now needed to understand whether and how the cases are related, says the zoonoses expert. In the past, he has already published studies on the occurrence of the monkeypox virus in chimpanzees (publication in Nature Microbiology) and sooty mangabey (publication in Emergent Infectious Diseases) in Cote d'Ivoire.

In another interview with Tagesschau, he comments on the transmission of the virus and symptoms: "The virus causes clear symptoms and with classical contact tracing, chains of infection can be traced to contain the outbreak."

The relationship of the monkeypox virus to the smallpox virus also has consequences for the vaccine. There is cross-reactivity between the viruses - the smallpox vaccine also protects well against monkeypox infection, although not 100%.

Smallpox vaccination can provide protection against monkeypox infection for many decades or lead to milder clinical symptoms

Prof Luka Cicin-Sain, Head of the Department “Viral Immunology”

This is what Prof Luka Cicin-Sain, Head of the Department “Viral Immunology” at HZI, says about people who were vaccinated against smallpox in childhood. In the FRG, compulsory smallpox vaccination was lifted in 1976, in the GDR only in 1982. Most young people are no longer vaccinated against smallpox and therefore have no protection. Despite its name, the chickenpox virus does not belong to the smallpox family, but to the herpes viruses. A chickenpox infection or vaccination therefore also offers no protection against monkeypox.

Monkeypox outbreak investigation in Nigeria 2017 - 2019

In 2017, a monkeypox outbreak was observed in several regions of Nigeria. The Department “Epidemiology” at HZI, headed by Prof Gérard Krause, then further developed the digital tool for disease control SORMAS (Surveillance, Outbreak Response Management and Analysis System) within a very short time and provided a monkeypox module. SORMAS helps to collect data on transmission routes and the geographical distribution of infection cases.

A research team led by Prof. Gérard Krause was involved in the investigation of a monkeypox outbreak in Nigeria from 2017 to 2019 and also used the SORMAS digital system to contain the outbreak. The scientists published their findings in the journals The Lancet Infectious Diseasesand Emerging Infectious Diseases.

On the current outbreak, Krause says:

Usually, the disease heals without consequences. In the epidemic we studied in Nigeria in 2017, there were about 6% deaths among the monkeypox cases recorded. However, it was not possible to find out to what extent these were predominantly caused by other concurrent diseases. It can be assumed that the proportion of deaths among monkeypox cases occurring in Europe will be significantly lower than at that time in Nigeria.

Prof Gérard Krause, Head of the Department “Epidemiology

Since the current outbreak in Europe is unusual, Krause sees some urgent questions that should now be investigated by research and health authorities. These include looking for direct or indirect links between people infected in Europe (e.g. personal contacts or exposures to rodents) and characterising those infected (age, immune status, gender, travel history). In addition, the molecular characteristics of the virus in different infected persons should be investigated and indications of monkeypox infections in contact persons that may have remained undetected should be sought.

Fighting epidemics in Nigeria with SORMAS-App


Zoonotic pathogens can be transmitted naturally from animals to humans or vice versa. Many new infectious diseases such as SARS-CoV-2, but also well-known diseases such as the plague, can be traced back to zoonoses. [read more]

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