Transmission of 2019-nCoV infection through asymptomatic contact in Germany.
Rothe et al, 2020 report in the New England Journal of Medicine issue of 5 March, 2020 a case of 2019-nCoV(note SARS-CoV-2) infection that occurred outside of Asia, where it appears that the infection (virus transmission/infection) occurred during the incubation period (this is the so-called index patient in the publication).
Rothe, C, Schunk M, Bretzel G, et al., 2020*. Transmission of 2019-nCoV infection from an asymptomatic contact in Germany, N Engl J Med 382;10 March 5, 2020.
https://www.nejm.org/doi/pdf/10.1056/NEJMc2001468?articleTools=true, accessed 25.03.2020.
- "A 33-year-old otherwise healthy German businessman (patient-1) became ill with strep throat, chills and myalgias on 24 January 2020, and developed a fever of 102.4°F (39.1°C) the following day, along with a productive cough.
- He started to feel better in the evening of the next day and went back to work on 27 January.
- Before the onset of symptoms, he had attended a meeting with a Chinese business partner at his company in Munich on 20 and 21 January.
- The business partner, living in Shanghai, had visited Germany between 19 and 22 January. During her stay, she had been well, with no signs of symptoms of infection.
- After her return flight to China, she tested positive for 2019-nCoV (SARS-CoV-2, the index patient) on 26 January.
- On 27 January, she informed the German company about her illness.
- The search for contact persons was started and the above-mentioned colleague was referred to the Department of Infectious Diseases and Tropical Diseases Medicine in Munich for further treatment.
- At the time of the clinic consultation, he was afebrile and healthy. He reported having no previous or chronic illnesses and had no history of foreign travel within the 14 days prior to the onset of symptoms.
- Two naso-pharyngeal swabs and a sputum sample were collected and found to be 2019-nCoV positive (SARS-CoV-2) by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR).
- The test revealed a high viral load of108 copies per millilitre in his sputum during the following days, with the last available result obtained on 29 January.
- On 28 January, three more company employees tested positive for 2019-nCoV.
- Of these patients, only patient-2 had contact with the index patient; the other two patients had contact only with patient-1.
- In consultation with the health authorities, all patients with confirmed 2019- nCoV infection were admitted to a Munich infectious disease unit.
- So far, none of the four patients has shown signs of severe clinical disease.
This case of 2019-nCoV infection was diagnosed in Germany and transmitted outside Asia. However, it is noteworthy that the infection was apparently transmitted during the incubation period of the index patient, in whom the disease was short and non-specific.
The fact that asymptomatic individuals can potentially be sources of 2019 nCoV infection may call for a reassessment of the transmission dynamics of the current outbreak.
In this context, the detection of 2019-nCoV and a high sputum viral load in a convalescent patient (patient-1) and also the prolonged release of 2019-nCoV after recovery is of concern.
Nevertheless, the viability of 2019-nCoV detected by qRT-PCR in this patient must be demonstrated by growing it in cell culture (viral culture).
(Note: molecular biological detection of specific SARS-CoV-2 RNA (RNA, ribo-nucleic acid) by pRT-PCR does not necessarily indicate that this RNA is infectious. The "gold standard" in virology to prove that the viral RNA is infectious is usually provided by growing the isolates (from sputum/throat swab) in vitro, in cell culture (e.g. on Vero cells, monkey kidney cells).
All four patients examined in Munich had mild symptoms and were hospitalised primarily for public health reasons.
As hospital capacity is limited - especially given the simultaneous peak of the influenza season in the northern hemisphere - further scientific research is needed to determine whether such patients can be treated(note guided?) outside the hospital by appropriate measures and with oversight".
The following scientists were involved in the collection of these data and the publication:
Camilla Rothe, M.D.
Mirjam Schunk, M.D.
Peter Sothmann, M.D.
Gisela Bretzel, M.D.
Guenter Froeschl, M.D.
Claudia Wallrauch, M.D.
Thorbjörn Zimmer, M.D.
Verena Thiel, M.D.
Christian Janke, M.D.
University Hospital LMU Munich, Munich, Germany
email@example.com(Note corresponding author)
Wolfgang Guggemos, M.D.
Michael Seilmaier, M.D.
Klinikum München-Schwabing, Munich, Germany
Christian Drosten, M.D.
Charité University Medicine Berlin, Berlin, Germany
Patrick Vollmar, M.D.
Katrin Zwirglmaier, Ph.D.
Sabine Zange, M.D.
Roman Wölfel, M.D.
Bundeswehr Institute of Microbiology, Munich, Germany
Michael Hoelscher, M.D., Ph.D.
University Hospital LMU Munich, Munich, Germany
Rothe et al, 2020 in their communication (N Engl J Med-Correspondence) have probably pointed out a first, significant difference between the SARS-CoV (pandemic 2002/2003) and the current SARS-CoV-2-(pandemic 2020) as far as the possibility of infection is concerned.
We recall: SARS-CoV transmission (infection) could probably be determined apparently bymeasuring elevated temperature of the SARS-CoV infected patient and thereby also controlling the spread to some extent. Based on available information, it appears that persons with SARS (SARS-CoV) were most likely to have been infectious only if they had symptoms such as fever or cough. SARS patients were most contagious during the second week of illness. However, as a precaution against the spread of the disease, the CDC recommends that people with SARS limit their interactions outside the home (e.g. by not going to work or school) until 10 days after their fever has subsided and their respiratory (breathing) symptoms have improved.
The Rothe et al., 2020 publication shows that infection by an infected person is possible before the infected person shows symptoms (and is therefore in the incubation period) and can thus become the source of infection.