According to Gunther Hartmann (Professor of Clinical Chemistry and Pharmacology at the University of Bonn) cited in this article (Süddeutsche Zeitung, in German)

Die Zahl der Erreger hat bei Erstinfektionen Einfluss auf den Schweregrad der Erkrankung.

My translation:

The number of pathogens during the initial infection affects the severity of the disease.

Leaving ethics aside I was wondering about the following:

  • Might it be an option to get infected by only a tiny amount, suffer only light symptoms and reach immunity (similar to a vaccination but probably more risky)?
  • Does the transmission path also affect the severity of the disease(inhaled vs. infected vs...)?

Edit: As Chris pointed out in his comment there is not enough research for Covid-19 yet so I would be also interested in findings from other viral infections.

  • 2
    $\begingroup$ Simple answer: We don't know yet as this disease is too new and we haven't done enough research on it. $\endgroup$
    – Chris
    Apr 9, 2020 at 11:32
  • $\begingroup$ @Chris Thanks for the comment, I edited the question. $\endgroup$
    – NashVio
    Apr 9, 2020 at 11:39
  • $\begingroup$ SE Biology is a question and answer site — not a discussion site — about the mechanisms of biological processes. Questions are generally answered by people with biological rather than those with medical or epidemiological expertise, who are more likely to be on SE Medical Sciences. Your question asks for subjective views on factors affecting the disease. Such questions are off-topic here. I draw your attention to a list of reputable sources for information about the pandemic on Meta. $\endgroup$
    – David
    Apr 9, 2020 at 17:45
  • $\begingroup$ @Chris In mice the severity is always dose-dependent (for short acting viruses), thus... Also I would mention Rotaredom answer is about the viral load found 1 week after the infection, it is related but not directly. And the viral load in the lungs is of course correlated with the (lack of) pneumonia and its severity thelancet.com/journals/laninf/article/PIIS1473-3099(20)30113-4/… thelancet.com/journals/laninf/article/PIIS1473-3099(20)30232-2/… thelancet.com/journals/laninf/article/PIIS1473-3099(20)30196-1/… $\endgroup$
    – reuns
    Apr 11, 2020 at 0:15

1 Answer 1


I think the answer to your question is actually found in the paragraph surrounding the quoted statement:

Auch Gunther Hartmann, Professor für Klinische Chemie und Pharmakologie an der Universität Bonn, berichtete, nach ersten vorsichtigen Einschätzungen sei davon auszugehen, dass der Schweregrad der Erkrankung über Hygienemaßnahmen reduziert werden könnte. "Die Zahl der Erreger hat bei Erstinfektionen Einfluss auf den Schweregrad der Erkrankung."

Approximate translation:

Gunther Hartmann, Professor of Clinical Chemistry and Pharmacology at the University of Bonn, also reported that, after initial careful assessments, it could be assumed that the severity of the disease could be reduced via hygiene measures. "The number of pathogens influences the severity of the disease in initial infections."

Notice that the language is not absolute but rather asumptive: "initial careful assessments," "It could be assumed," "could be reduced." It's tentative language and suggests that research is ongoing. Furthermore, if you search for that quote, you'll find that this is not published in peer-reviewed journals; it's simply a preliminary observation to encourage the public to limit intake of pathogens.

We already know that in some other cases the viral load affects the severity of symptoms. But we don't actually know that that's the case with COVID-19. In fact, initial reports from Italy suggest that there is no statistical difference between viral loads between symptomatic and assymptomatic cases of COVID-19. So Chris's short answer is absolutely right; we don't know. For all practical purposes, it's just as well to assume that it's the case, as it will lead to more hygeinic practices, but further research will be required to demonstrate that it is actually the case.


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