F&L: How is monkeypox diagnosed?
Hartmut Hengel: The evidence is provided by swab material from the patients. In it, the virus genome, the MPXV DNA, is detected by the polymerase chain reaction (PCR); i.e. similar to the corona detection.
F&L: With a view to the corona pandemic, many were concerned that the next pandemic could already be imminent. To what extent does monkeypox have the potential to become a pandemic?
Hartmut Hengel: Pandemics result from the change of host from zoonotic pathogens to humans. Such a fundamental change in the existence of the infectious agent requires decisive changes in its genetic program. Therefore, RNA viruses such as influenza or corona viruses with their relatively high mutation rates appear much more frequently as pandemic pathogens than DNA viruses, which have lower mutation rates. Sporadic transmissions of the MPXV pathogen to humans have been observed for decades in places where the virus is endemic, ie where it circulates continuously. MPXV occurs in separate clades in rodents and squirrels in Central and West Africa, respectively, and transmission from these reservoirs to primates appears to be common. What is qualitatively new is the ongoing establishment of human-to-human transmission and the associated global spread of this MPXV strain on all continents. We are thus witnessing the transformation of an originally zoonotic pathogen into a human-adapted MPXV. This process is favored by the general absence of orthopox immunity in the population. With the newly emerged global distribution, MPXV meets a criterion for a pandemic, but lacks high infection rates and a burden of disease that threatens society. The low baseline reproduction rate of MPXV is associated with the predominant routes of transmission, which are skin and mucosal contact, such as sexual contact. But the relatively environmentally resistant infectious viruses can also be passed on through everyday objects. It is unclear whether there is any appreciable transmission via the respiratory tract.
“The monkeypox virus appears to have undergone ‘accelerated evolution’.”
F&L: How (un)usually fast or far has monkeypox spread compared to previous local outbreaks in Africa?
Hartmut Hengel: In fact, the current outbreak is different with currently 65,000 reported cases from more than 107 countries, and yet the number of infections in Germany and some other countries is now falling significantly again. The current outbreak pathogen is clearly different from the virus variants that were detected in sporadic outbreaks just a few years ago. The monkeypox virus appears to have undergone “accelerated evolution”. This is seen as an expression of better genetic adaptation to humans. The interim decrease in the number of infections in Germany is probably due to the fact that during the current outbreak the virus spread predominantly among men who have sex with men (MSM), especially in the mobile and more promiscuous MSM communities. These men are now well informed and successfully protect themselves, for example through vaccination.
F&L: What does it mean that some people outside the initially observed group of people affected (MSM) have now also become infected? Was the initial observation fallacious as a result of incorrect assumptions or as a result of poor evidence or collection methods?
Hartmut Hengel: Viruses depend on transmission events and on susceptible hosts for their existence, in other words on sufficient contacts between their hosts. Even in social groups that appear to be strongly related to one another, there are external contacts and thus “spill over” events of the pathogen. Incidentally, in the case of an originally zoonotic pathogen such as MPXV, this also includes transmission to pets. It must therefore be expected that MPXV will also spread can increasingly establish itself outside of the MSM community.
F&L: Is the first reaction to monkeypox similar to the first reaction to HIV, which was initially wrongly dismissed as “unimportant” and a disease only homosexuals can contract?
Hartmut Hengel: Many new infectious diseases initially lead to misperceptions. This includes disregard, repressive projections on social minorities such as MSM, but also fear of illness and hypochondria. Reports of MPXV infection in women, children, and pets can help break these stereotypes.
“Many new infectious diseases initially lead to misperceptions.”
F&L: Why did the WHO only classify the outbreak of the disease as an “emergency of international concern” about two months later?
Hartmut Hengel: The WHO has needed time to collect reliable data from different WHO regions and to prepare technical assessments for decisions. The ad hoc committee set up was confronted with a new and unexpected situation that required a coordinated decision with significant implications for the international community, for example with regard to the distribution of the very scarce vaccine and drug stocks. This is not an easy matter and everyone knows that WHO is in a difficult political and financial situation.
F&L: When are you, as a virologist, on alert in the event of an outbreak?
Hartmut Hengel: As a clinical virologist, you are generally in standby mode, or ‘on alert’. This means that you have to master the appropriate diagnostic procedures and be able to make them available in the shortest possible time with the help of your professional networks. The next stage is followed by the requirements of molecular surveillance, i.e. monitoring in the laboratory using rapid full genome sequencing and bioinformatic analyzes in order to understand phylogenetic relationships – i.e. the origin of pathogens – and to clarify transmission chains. It is only thanks to the Covid-19 pandemic that we in Germany have the insight that we need serious, continuous “pandemic preparedness” and that this cannot be achieved without reliable, sustainable structures in our health and science system. For virology, this means that we High-security laboratories, molecular surveillance and, last but not least, need young academics and doctors.
F&L: Do we humans possibly underestimate the danger posed by monkeypox because we are currently used to a more threatening infectious disease with Corona? How quickly can the risk of monkeypox escalate again?
Hartmut Hengel: Our society is about to learn more composure in dealing with the corona virus and at the same time to take precautions. The experiences from the Covid-19 pandemic can certainly be helpful with future new infectious agents, although each pandemic will be determined by the respective agent and will take a different course. So far there has been no general danger from the MPXV pathogen. However, such a situation could develop in the future if MPXV can further increase its transmission advantages. Because of the much slower evolution of MPXV as a DNA virus compared to Sars-CoV-2, an RNA virus, MPXV gives those responsible for health policy more time to take precautions.
F&L: What medical and epidemiological countermeasures do you consider necessary and sensible to curb the spread of monkeypox?
Hartmut Hengel: In my opinion, the strategic build-up of sufficient vaccine stocks must be the priority at this point in time, especially since the MPXV vaccine also decisively thwarts the use of the variola pathogen as a biological weapon and the associated option of hybrid warfare. Pharmacologically effective antivirals, i.e. drugs for infected people, are available to some extent, but their preventive effectiveness is unclear and not comparable to that of vaccines.
“We don’t know from which corner the next pandemic pathogen will come.”
F&L: What kind of research will help with further containment? Where are there research gaps?
Hartmut Hengel: With the eradication of the human smallpox pathogen and the abolition of the vaccinia vaccination against smallpox, research on smallpox viruses had lost its importance and research funds. There is a very strict research ban on the variola pathogen. That needs to be reconsidered. In the future, virological research must do more justice to the enormous biodiversity of viral pathogens, because we do not know from which corner the next pandemic pathogen will come.