Skip to main content

Service: Sources Podcast Christian Drosten / NDR

Prof. Dr. Christian Drosten - Berlin site manager of the National Research Platform for Zoonoses - includes in his considerations in his much-received podcast on NDR a large number of studies that are currently published on pre-print servers. As a special service we have linked the studies to the individual episodes below.

Link to the episode (German)


Christophe Fraser/ Feretti et al.

Calculation of the proportion of pre-sympathetic, sympathetic and asympathetic transmissions, etc.
Efficiency of different measures, hypothetical app with contact tracing and information to persons who were in the vicinity
→ Even if isolation is carried out immediately at the onset of symptoms, there are already infected persons from the isolated person as well as from those infected
Transmission via surfaces evaluated as a maximum of 10% (mentioned in episode 28)

Chen et al.  (Chinese Chloroquine Study)

Small randomized study groups, but small, significant improvement effect visible, comparability of both test groups not fully clarified


Link to the episode (German)


Measures that are recommended by "Leopoldina"

→ With masks and voluntary apps until mid-May below 1.0 newly infected persons per infected person possible

Mask study from Hong Kong (pre sars-cov2)

→ 11 Coronavirus-infected persons with mask, after 30 minutes no virus found in the room air, in 10 infected persons without mask already

Publication on stability of sars-cov2 (New England Journal)

In aerosol, virus is still infectious for 3 hours (but only under laboratory conditions with high virus concentration)

Study from Singapore, indoor air analysed over several days
SARS-CoV2 patients, One patient (day 9) with little virus in airways → in ambient air nothing detectable; 2 patients with much virus in airways, to both droplet sizes in ambient air virus RNA detectable. (→ Transmitted by breathing in ambient air possible)
Wipe samples were also taken from surfaces in 30 hospitals. Only in first week of symptoms
positive wipe samples! → The later in the disease the less infectious.

Study from Iran: loss of taste and smell described
Symptom more frequently described in a family of sufferers of olfactory system failure than respiratory problems

Mentioned in the note:
Belgian study on the same phenomenon

Link to the episode


Dutch study "Virus in wastewater as an indicator"

SARS-cov2 RNA detectable in wastewater (This does NOT mean that this wastewater is infectious)

also: "Munich Study" by Charité Berlin

No infectious virus detectable from stool RNA

Link to the episode (German)


"Munich Study" (already mentioned in episode 29)

Excretion over time in 9 patients (detection limit of PCR visible) 
-> statistical distribution phenomena, as virus is present but not always detectable
(Explanation for alleged reinfections in discharged patients in South Korea)


Reference to:

First study from Wuhan (5/55 recovered patients tested positive again)

Unsicherheit über die Abstrichmethode (einige Arten von Proben sind signifikant länger positiv als andere)

Zweite Studie aus Wuhan (25/172 genesene Patienten wieder positiv getestet)

Im Mittel 5,23 Tage nach Entlassung wieder positiv getestet,
Entlassungskriterium waren 2 negative Rachenabstriche (dieser Probentyp ist sehr früh negativ) hintereinander

Link to the episode (German)


Epidemiological study on Italian village

Almost all inhabitants of the small village were tested twice and asked about symptoms.
-> 43.2% asymptomatic Covid19 cases.  However, just as high virus excretion!


Californian antibody study with ELISA rapid test

1.5% of those tested; after calculation on age groups 2.8% of the population with antibodies;
of positive controls (known infected) only 70% detected. 
-> Population prevalence in the lower single-digit percentage range, thus still far from herd immunity

Icelandic study, from which it was concluded that children under 10 years of age would not be infected

Test subjects were once returnees from risk areas and their contact persons,
once volunteers (without too strong symptoms), therefore rather no asymptomatic cases, 
as they often seem to be with children -> significance difficult to judge

Study from Shenzen

Cohort study with 1286 contacts of 400 infected persons.
Attack rate (rate of contacts of infected persons who also became infected) the same
between different age groups from 0-9, 10-19 and 20-30 years.

However, only one study, no data on virus excretion between children and adults

Study from Hong Kong by Gabriel Leung

"44% of transmission before symptoms begin"
Most infectious day the day before the onset of symptoms, after 4 days usually hardly infectious, after one week not at all

Link to the episode (German)


English Office for Statistics on Mortality during Corona

New York Times, charts of mortality curves from different countries

Significant increase up to doubling of the mortality rate in various countries, despite measures in these countries
Many countries with a 'missed' month, because they only reacted to rising death rates. Germany with a lead

Modelling study from France

Even after a long lockdown from epicenters of the epidemic, little has been achieved,
2.6% of infected persons have to go to hospital, infectious mortality rate modelled at 0.53%,
8.3 % for over 80-year-olds (retirement homes omitted)

Link to the episode (German)


Statement by Ranga Yogeshwar on the question whether the "lockdown" was for nothing (German)

When viewing the reproduction figure curve of the RKI, prior soft measures and
the change in test capacities can be included. The effect of the lockdown at the beginning of April is also
can be recognized by a bend in the curve.


Vaccination study on rhesus monkeys from Beijing

Eight rhesus monkeys vaccinated (dead vaccine) and infected. 
Vaccinated animals without lung damage, almost no virus replication to be found.
Furthermore no side effects like a boosted immune reaction.

Study on T-helper cells, by Charité Berlin

Indications of T cell immunity after coronavirus-induced cold. 
However: Not necessarily 30% of Germans are immune, even negative effects are conceivable,
or explanation for many asymptomatic to mild cases

Link to the episode (German)


Household contact study from Wuhan

Children without symptoms, but 15% of children in households with first-time infections infected in the observation period
i.e. just as frequently as all other age groups


Study from the Netherlands

Broken down by contact person, children had much less contact with infected persons, but not significant, as only a few children were included in the study


Basic study on autophagy from Bonn

Like the MERS virus, SARS-Cov2 interferes with autophagy via the Beclin-2 network, 
Autophagy supporting pharmaceuticals like niclosamide, MK-2206, spermidine could help.
→ Permitted concentration of niclosamide prevents virus in vitro, therefor currently applying for clinical trials on infected persons

Link to the episode (German)


Analysis of viral load by age of patients at Charité Berlin

Children not with lower virus concentration in respiratory tract than adults; the (few) symptomatic children rather with lower virus concentration (!)

The Lancet study: Contacts in households text

Children and adults with an infection rate of approximately 12%.

Science study from Shanghai on the risk of infection for children

6.2 % of children (0-15), 8.6 % of adults in index patient infected, but with included probability of contact, children have only one third of the risk of infection

Link to the episode (German)


"Heinsberg Study" from Gangelt by Dr. Streeck (Bonn)

High number of unreported cases; projected 1.8 million infections in Germany (10 times as high as the official figure), -> Still a long way to herd immunity; 
Infection mortality rate of 0.36% (confirmed antibody tests were not included in this calculation) 


Study on high school in Oise (Northern France)

5 weeks of unnoticed outbreak in school, 38.3% students, 43.4% teachers, 60% other employees infected
but possibly not representative (voluntary nature of the study with mutual effects)


Study on the risk of infection for smokers

Only "strikingly" low proportion of smokers among infected persons in French university hospital -> Does not mean that courses are also easier
No explanation provided, must first stand up to scrutiny (Dr. Drosten is not convinced yet)


Data from 15 schools in Australia

Only low attack rates of students, study not yet completed, no scientific publication (not even preprint),
nevertheless already translated into political decisions


Geneva study by Isabella Eckerle

23 children's cases (between 0 and 16 years) from hospitals and sending practices were examined,
on average considerable virus concentration with infectious virus, in younger children perhaps lower 
-> No statistical reason to assume that virus concentration in children is different from that in adults

Link to the episode (German)


Study on antigen test

"Pregnancy test for sars-cov2" with monoclonal antibodies of the sars virus' from 2003,
75% of highly infectious patients detectable, low infectious patients poorly detectable
-> helpful for first decision making in emergency rooms etc


Study from Toronto on the significance of saliva tests

Thai study on the same question

US study

-> Saliva samples in comparison to other respiratory diseases Saliva samples in
Covid19 very sensitive; slightly less accurate (in Thai study compared to double smear) to better (US study) than smear
Less prone to sampling errors

Link to the episode (German)


Chinese study (mentioned)

Aerosol transmission component quite a factor, shown in restaurant in Guangzhou


Modelling study by Columbia University

Two different models for possible second wave in May


Study from France

Sample of a pneumonia patient from December 2019 tested positive for SARS-COV2 by PCR,
but without further testing and sequencing of the virus, obviously too much positive control -> cross-contamination?


Chinese study on SARS-like viruses in bats

cleavage site in the spike protein as well as in SARS-COV2


Study from Los Alamos

Hypotheses on changes in infectiousness based on molecular changes in the spike protein,
Wuhan virus without mutation seems to be harmless compared to the virus that came into the world from Shanghai,
but possibly only by chance, as no clear difference in fitness has been shown so far

Link to the episode (German)


Economic study

Dance with the tiger, slow, assured loosening most effective, because quarantine measures
may be more economically harmful than light restrictions; R=0.75 optimal for economy
and also good for health


Hamburg study

virus replicates in various organs, including kidneys and damages them


Studies on Kawasaki syndrome-like clinical picture text

Vascular inflammation apparently caused by SARS-COV2, also observed in children,
fortunately rare and treatable

Link to the episode (German)


Epidemiological study from Italy

excess mortality in Italy much higher than the officially reported Corona deaths
in a small Italian town of 11,500 inhabitants with a mortality rate 15 times higher than normal


NYT report on Covid19 outbreak in Nigerian town of Kano

Relatively small number of cases documented, but a large number of infected persons among tested doctors


Study on the mortality risk of swine flu

As many deaths as during normal flu waves, but a great many middle-aged adults were affected by swine flu
affected, -> cross-immunity of old people by H1N1 virus of the Spanish flu and subsequent years -> was unexpected

Link to the episode (German)


Statement of the German Society for Pediatric Infectiology

Claim: "Children play a subordinate role in the spread of SARS-CoV2",
However, the introduction of the virus by children into the family should not be investigated;
nevertheless important contribution to the discussion


Japanese Study

19 times the risk of being infected indoors compared to outdoors


Chinese study on household outbreaks

108 out of 318 outbreaks associated with public transport, only 14 with restaurant visits

Another Chinese study on attack rate by age group

U18-year-olds only infected by index patients in 4% of households, but 17.1% of adults,
but which, under Chinese quarantine conditions.


Study from Geneva in Switzerland on attack rate

5-19-year-olds and 20-49-year-olds here without major differences (no other age groups examined)


Swedish study

Random samples tested with PCR, no significant differences of
Distribution of infected persons between children and adults

Link to the episode (German)


Study on stochastics

Research group names 4 categories of superspreading events: opportunities (choir, cruise, etc.), permanent venues (such as accommodation),
social behaviour and unknown biological factors


Review in "Science" by Kai Kupferschmidt


"Nature" study by Lloyd Smith

Prevent social situations that encourage many infections:
At a control power of 30% (assuming masks are that effective), which is only half as effective in 20% of the most infectious persons
"arrives", an epidemic of the magnitude SARS-1 (dispersion factor 0.1) must be stopped.


Swiss study from January

Dispersion factor estimated at 0,3 to 0,6


London study

Assume 10% "superspreaders"; estimate dispersion factor 0.1 to 0.3,
Data basis (from countries other than China) uncertain 


Hong Kong Study by Gabriel Leung

Cluster with minimum size in Hong Kong studied, dispersion factor of 0.45,
Even with early isolation several people are already infected -> Isolation in
Cluster candidates must be done before diagnostics!


Link to the episode (German)


Study on effect of measures from "The Lancet text


Investigation of Remdesivir as a drug against Covid19

Used in patients with severe course, but little effect
-> Works against virus, but not against inflammation

Link to the episode (German)


Virus load of the Charité (updated study)

More precise statistical methods used; distinction between the origin of the samples (for example, outpatient clinic or intensive care unit);
intensive care patients often already in the second week of illness and thus hardly any virus in throat swabs;
At least 30% of children with a high viral load; no difference in the mean value according to age


Study by Viola Priesemann in "Science

Model calculation for effect of measures in Germany; ban on major events reduced propagation rate from 0.43 to 0.25;
school closures then down to 0.15; after general contact limitation down to 0.09


Preprint from Oxford

Effects of nine different measures examined; data from 41 countries;
school closures in the period of expansion strongest effect in this model (50% reduction)

Link to the episode (German)


Localization of infected tissue types with GFP

Green fluorescent protein incorporated into virus to mark infected cells in tissues;
SARS-Cov2 particularly often found in nasal mucosa epithelium


Link to the episode (German)


Study on susceptibility of different blood groups

Higher risk of a severe course with blood group A,
little heavy with blood group 0


New antibody study from Zurich

IgA antibodies in addition to IgG antibodies;
Symptomless positives without IgG, but already with IgA antibodies;
-> apparently local IgA infection


Study on the effect of the prevented effects

Germany with only 0.85 % infected compared to England, Italy, France and Spain with several percent,
several hundred thousand deaths acceptable without any measures at all


Study from California by economists

Without measures, a daily growth rate of up to 38% could have been possible (based on rough estimates)


Study on compulsory masks in Jena

Comparison of a hypothetical maskless Jena with the actual Jena; 23% less increase of infections;
Apparently, "announcement effect" also visible;
in addition, a comparison of districts: districts with compulsory masks 40% less increase per day compared to comparable districts without compulsory masks