Top 10: December 10


Chan NC, Li K, Hirsh J. Peripheral Oxygen Saturation in Older Persons Wearing Nonmedical Face Masks in Community Settings. JAMA December 8, 2020. 2020; 324(22):2323-2324. Full-text:

Some people still claim on social media that masks can cause hypoxia and are therefore dangerous. Please forget this nonsense. Noel C. Chan provided participants aged 65 years or older with a 3-layer plane-shaped disposable non-medical face mask with ear loops (Boomcare DY95 model) and a portable pulse oximeter. In their cross-over study on 25 subjects, wearing a 3-layer nonmedical face mask was not associated with a decline in oxygen saturation.



Ismail SA, Saliba V, Bernal JL, et al. SARS-CoV-2 infection and transmission in educational settings: a prospective, cross-sectional analysis of infection clusters and outbreaks in England. Lancet Inf Dis December 08, 2020. Full-text:

In this prospective, cross-sectional analysis of educational settings in England that had re-opened after the first national lockdown, SARS-CoV-2 infections and outbreaks were uncommon. Among 55 outbreaks (at least two epidemiologically linked cases, with sequential cases diagnosed within 14 days in the same educational setting), probable direction of transmission was staff-to-staff in 26, staff-to-student in 8, student-to-staff in 16 outbreaks, and student-to-student in 5 outbreaks. The risk of an outbreak increased by 72% (95% CI 28–130) for every five cases per 100.000 population increase in community incidence, emphasizing the importance of controlling community transmission to protect educational settings. Interventions should focus on reducing transmission in and among staff.

See also the comment by Flasche S, Edmunds JW. The role of schools and school-aged children in SARS-CoV-2 transmission. The Lancet Infectious Diseases. December 8, 2020. Full-text:



Fu Y, Li Y, Guo E, et al. Dynamics and Correlation Among Viral Positivity, Seroconversion, and Disease Severity in COVID-19: A Retrospective Study. Ann Intern Med. 2020 Dec 8. PubMed: Full-text:

A huge study on viral kinetics that may enrich our understanding of the various patterns of SARS-CoV-2 positivity and the disease course: In 2142 patients with laboratory-confirmed COVID-19, the viral positivity rate peaked within the first 3 days. The median duration of viral positivity was 24,0 days (95% CI, 18,9 to 29,1 days) in critically ill patients and 18,0 days (CI, 16,8 to 19,1 days) in non-critically ill patients. Being critically ill was an independent risk factor for longer viral positivity. In patients with laboratory-confirmed COVID-19, the IgM-positive rate was 19,3% in the first week, peaked in the fifth week (81,5%), and then decreased steadily to around 55% within 9 to 10 weeks. The IgG-positive rate was 44,6% in the first week, reached 93,3% in the fourth week, and then remained high.



Voysey M, Clemens SA, Madhi SA, et al. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. Lancet December 08, 2020. Full-text:

60-70% protection: this is what we can probably expect from inactivated vaccines. This important paper describes the first interim safety and efficacy data for a viral vector coronavirus vaccine, ChAdOx1 nCoV-19 (AZD1222, developed at Oxford University), evaluated in four trials across three continents. Between April 23 and Nov 4, 2020, 23.848 participants were recruited and vaccinated: 1077 in COV001 (UK), 10.673 in COV002 (UK), 10.002 in COV003 (Brazil), and 2096 in COV005 (South Africa). The vaccine showed significant vaccine efficacy of 70,4% after two doses and protection of 64,1% after at least one standard dose, against symptomatic disease. Across all four studies, the vaccine had a good safety profile with serious adverse events and adverse events of special interest balanced across the study arms. The efficacy of 90,0% seen in those who received a low dose as prime in the UK by error (COV002, read how this dosing error happened and about the implications) was intriguingly high compared with the other findings in the study. However, this has to be confirmed. Moreover, pre-specified sub-group analyses (elderly, those with comorbidities) were not included in this report. Of note, the ChAdOx1 vaccine can be easily administered in existing healthcare systems (in contrast to mRNA vaccines), stored at ‘fridge temperature’ (2-8 °C) and distributed via existing logistics.


Knoll MD, Wonodi C. Oxford–AstraZeneca COVID-19 vaccine efficacy. Lancet December 08, 2020. Full-text:

In their comment on the ChAdOx1 paper, Maria Deloria Knoll and Chizoba Wonodi are enthusiastic: “Despite the outstanding questions and challenges in delivering these vaccines, it is hard not to be excited about these findings”. They believe that “perhaps by this time next year, we can celebrate the global control of SARS-CoV-2, in person”. We‘ll see.


Pfizer / BioNTech. Vaccines and Related Biological Products Advisory Committee Meeting December 10, 2020. FDA submission 2020, published 8 December 2020. PDF: 1) FDA document – 2) Sponsor document

On December 10, Pfizer and its partner, the German company BioNTech, will be publicly reviewed by the FDA. Find here two documents (53 and 92 pages, respectively) which go into the details of the Phase III trial on 44.000 volunteers recruited in the United States, Brazil and Argentina. Among the first 170 infected persons, 162 had received the placebo and 8 the vaccine – an effectiveness of 95%. The documents disclose more details about protection after the first vaccine dose as well as the protection of elderly people, obese people and those suffering from co-morbidities. There seem to have been no significant differences between the vaccinees and the placebo group in the few serious complications recorded. However, moderate side effects were recorded after the second injection: headache, fatigue, muscle pain and chills affected up to 50% of the vaccinees, particularly those under 55 years old.



Lazzeroni D, Concari P, Moderato L. Simultaneous COVID-19 in Homozygous Twins. Ann Intern Med. 2020 Dec 8. PubMed: Full-text:

Interesting case report: on 9 March 2020, male twins from Italy who were 60 years old and considered homozygous because of their appearances and other personal characteristics, were diagnosed with SARS-CoV-2 infection (probably transmitted by the same index patient). Despite a similar viral load at diagnosis, both twins had very different clinical courses (one with mild-to-moderate disease, one with critical COVID-19, requiring mechanical ventilation). Bottom line: everyone is unique (even homozygous twins).

Figure. Body temperature (A), Pao2/FIo2 ratio (B), C-reactive protein level (C), and leukocyte count (D) during the first 2 weeks of hospitalization, which was from admission to discharge for twin 1 and admission to transfer to the intensive care unit for twin 2.



Pun KY, Kok AA, Eikelenboom M. The mental health impact of the COVID-19 pandemic on people with and without depressive, anxiety, or obsessive-compulsive disorders: a longitudinal study of three Dutch case-control cohorts. Lancet Psychiatry December 08, 2020. Full-text:

Between April 1 and May 13, 2020, online questionnaires were distributed among ongoing cohorts from the Netherlands, including people with (n = 1181) and without (n = 336) depressive, anxiety, or obsessive-compulsive disorders. People without depressive, anxiety, or obsessive-compulsive disorders showed a greater increase in symptoms during the COVID-19 pandemic, whereas individuals with the greatest burden on their mental health tended to show a slight symptom decrease.



Trapani S, Masiero L, Puoti F, et al. Incidence and outcome of SARS-CoV-2 infection on solid organ transplantation recipients: A nationwide population-based study. Am J Transplant. 2020 Dec 5. PubMed: Full-text:

Registry case data from Italy: the cumulative incidence of SARS-CoV-2 infection in solid organ transplantation recipients (SOTRs) is three times higher than that estimated for the Italian population, highlighting that SOTRs are more at risk of infection than non-SOTRs. The 30- and 60-day cumulative incidence of mortality of COVID+ SOTRs was twice as high when compared to non-SOTRs.



If you read French, read Herzberg N, Aeberhardt C. Covid-19 : les surprises et les enseignements des essais des vaccins d’AstraZeneca et de Pfizer. Le Monde 2020, published 9 December. Full-text :

La revue « The Lancet » a publié les résultats complets du laboratoire britannique, tandis que la FDA a rendu publics ceux du groupe américain.


Pineau E. Vaccins contre le Covid-19 : médecins et scientifiques demandent plus de transparence. Le Monde 2020, published 9 December. Full-text :

Des vaccins élaborés en pleine pandémie due au coronavirus, une campagne de vaccination de masse amorcée sans données scientifiques exhaustives… Pour de nombreux spécialistes, la situation est inédite.


Copy-editor: Rob Camp


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