Top 10: April 4

<<< April 2020

By Christian Hoffmann &
Bernd S. Kamps


Ferretti L, Wymant C, Kendall M, et al. Quantifying SARS-CoV-2 transmission suggests epidemic control with digital contact tracing. Science 31 Mar 2020.

Using an analytically solvable model, authors show that viral spread is too fast to be contained by manual contact tracing. Spread could be controlled if this process was faster, more efficient and happened at scale. A contact-tracing App which builds a memory of proximity contacts and immediately notifies contacts of positive cases can achieve epidemic control if used by enough people, without need for lockdowns.


Flaxman S, Mishra S, Gandy A. Estimating the number of infections and the impact of non-pharmaceutical interventions on COVID-19 in 11 European countries. March 30.

Infection-control measures such as national lockdowns in many European countries are reducing the spread of the coronavirus. Across 11 countries, between 21,000 and 120,000 deaths were probably avoided by the end of March, according to a model by a group at Imperial College London.


Leung NH, Chu Dk, Shiu EY. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nature Med 2020, April 3.

Do face masks work? Yes, but it depends. This important study from Hong Kong (performed 2013-16) quantified virus in respiratory droplets and aerosols in exhaled breath. In total, 111 participants (infected with seasonal coronavirus, influenza or rhinovirus) were randomized to wear (or not) a simple surgical face mask. Results suggested that masks could be used by ill people to reduce onward transmission. But note the small numbers: in respiratory droplets, seasonal coronavirus was found in 0/11 droplets (aerosols: 0/11) from participants wearing face masks, compared to 3/10 (aerosols: 4/10) without masks. Influenza viruses were detected in 1/27 (aerosols 6/27!) with face masks, compared to 6/23 (8/23) without. For rhinovirus, there were no significant differences at all. Of note, authors also identified virus in some participants who did not cough at all during the 30-min exhaled breath collection, suggesting droplet and aerosol routes of transmission from individuals with no obvious signs or symptoms.


Chin AW, Chu JT, Perera MR, et al. Stability of SARS-CoV-2 in different environmental conditions.The Lancet Microbe 2020, April 02. Full-text:

Don’t put your masks in the fridge for recycling! Heating is probably better. This important work shows that the virus was highly stable at 4°C (almost no reduction on day 14) but sensitive to heat (70°C: inactivation 5 min, 56°: 30 min, 37°: 2 days). It also depends on the surface: No infectious virus could be recovered from printing and tissue papers after 3 hours, from treated wood and cloth on day 2, from glass and banknote on day 4, stainless steel and plastic on day 7. Strikingly, a detectable level of infectious virus (∼0·1% of the original inoculum) could still be present on the outer layer of a surgical mask on day 7.



Gane SB, Kelly C, Hopkins C. Isolated sudden onset anosmia in COVID-19 infection. A novel syndrome? Rhinology. 2020 Apr 2. pii: 2449. PubMed: Full-text:

Case report and series on isolated sudden onset anosmia, urgeing to consider this presentation.



Meng J, Xiao G, Zhang J, et al. Renin-angiotensin system inhibitors improve the clinical outcomes of COVID-19 patients with hypertension. Emerg Microbes Infect. 2020 Dec;9(1):757-760. PubMed: Full-text:

First study argueing against any deleterious effect of RAAS inhibitors (ACE inhibitors or sartans) in COVID-19! Among 42 of 417 patients admitted to Shenzhen Hospital while on antihypertensive therapy, those receiving RAAS inhibitors had a lower rate of severe diseases than patients without (5/17 compared to 12/25) and a trend toward a lower level of IL-6 in peripheral blood.


The Lancet Oncology. COVID-19: global consequences for oncology. Lancet Oncol. 2020 Apr;21(4):467. PubMed: Full-text:

Thoughts on how the pandemic affects treatment of patients with cancer and how it will hit the wider oncology community. Substantial changes for research, education, and collaboration are expected, including reduced international travel and increased remote networking and telemedicine.



Tay JK, Koo ML, Loh WS. Surgical Considerations for Tracheostomy During the COVID-19 PandemicLessons Learned From the Severe Acute Respiratory Syndrome Outbreak. JAMA Otolaryngol Head Neck Surg. Published online March 31, 2020. Full-text:

Patients with prolonged ventilation may require tracheostomy to optimize weaning from ventilatory support. Review of the literature and practical issues.



Petherick A. Developing antibody tests for SARS-CoV-2. The Lancet 2020, April 4, Vol. 395, No. 10230. Full-text:

Brief report about current knowledge and development on antibody testing.



Chen C, Huang J, Cheng Z, et al. Favipiravir versus Arbidol for COVID-19: A Randomized Clinical Trial. Posted March 27, medRxiv 2020.03.17.20037432. Full-text:

Important open-label, randomized trial conducted in 3 hospitals from China, comparing arbidol and favipiravir in 236 patients with COVID-19 pneumonia. Primary outcome was the 7 day clinical recovery rate (recovery of fever, respiratory rate, oxygen saturation and cough relief). In “ordinary” COVID-19 patients (not critical), the recovery rates were 56% with arbidol (n=111) and 71 % (n=98) with favipiravir (p=0.02) that was well tolerated, except for some elevated serum uric acid levels. Striking! But can we trust? In the whole study population, no difference was evident. Many cases were not confirmed by PCR. There were also imbalances between subgroups of “ordinary” patients and even favipiravir was incorrectly spelt 7 times: 3x famiravir, 4x fabiravir (come on guys – did anybody read the manuscript?). This paper needs a careful (and major) review…