Top 10: January 15

Copy-editor: Rob Camp


Ledford H. COVID reinfections are unusual — but could still help the virus to spread. Nature 2021, published 14 January. Full-text:

A large study of UK healthcare workers suggests that most people are immune for months after catching COVID-19 for the first time.


Ashby B, Best A. Herd immunity. Curr Biol 2021, published 12 January. Full-text:

If you want to do some math, read this short paper and revise a concept neither Boris Johnson (how could he!) nor his advisers really understood. In short: as immunity accumulates in a population — naturally during the course of an epidemic or through vaccination — the spread of infectious disease is limited by the depletion of susceptible hosts. In this primer, Ben Ashby and Alex Best discuss the concept of herd immunity from first principles, clarify common misconceptions, and consider the implications for disease control.



Sadoff J, Le Gars M, Shukarev G, et al. Interim Results of a Phase 1–2a Trial of Ad26.COV2.S Covid-19 Vaccine. N Engl J Med 2021, published 13 January. Full-text:

Hanneke Schuitemaker, Jerald Sadoff and colleagues describe the safety and immunogenicity profiles of Ad26.COV2.S. As with other SARS-CoV-2 vaccines, the most frequent adverse events were fatigue, headache, myalgia, and injection site pain. Systemic adverse events were less common in people 65 years or older than in those 18 to 55 years of age. Neutralizing-antibody titers against wild type virus were detected in 90% or more of all participants on day 29 after the first vaccine dose and reached 100% by day 57 with a further increase in titers (GMT, 288 to 488), regardless of vaccine dose or age group. Ad26.COV2.S, developed by Janssen Pharmaceutical Companies of Johnson & Johnson, is a recombinant replication-incompetent adenovirus type 26 (Ad26) vector-based COVID-19 vaccine encoding a prefusion-stabilized SARS-CoV-2 Spike immunogen.


Efrati I. Israel to Share Vaccination Data With Pfizer as Part of Secret Deal. Haaretz 2021, published 10 January. Full-text:

The Israeli newspaper reports a deal between Israel and Pfizer: Pfizer will receive anonymized data about consequences of the inoculations, side effects, efficacy, and the amount of time it takes to develop antibodies, according to different types of population, age, gender, pre-existing conditions, and other factors.



Venkatesan P. NICE guideline on long COVID. Lancet Respir Med 2021, published 13 January. Full-text:

While discussing the NICE guidelines on long COVID published a few weeks ago, Priya Venkatesan gives a short overview of the condition. The guideline defines long COVID as (1) ongoing symptomatic COVID-19 for people who still have symptoms between 4 and 12 weeks after the start of acute symptoms; and (2) post-COVID-19 syndrome for people who still have symptoms for more than 12 weeks after the start of acute symptoms. Patients with new or ongoing symptoms 4 weeks or later after acute infection should receive a full blood count, kidney and liver function tests, a C-reactive protein test, and an exercise tolerance test (recording level of breathlessness, heart rate, and O2 saturation). The guidelines also recommend that a chest x-ray should be offered to all patients by 12 weeks after acute infection if they have continuing respiratory symptoms. [COVID-19 rapid guideline: managing the long-term effects of COVID-19 – NICE guideline [NG188]. Access:]



Joyner MJ, Carter RD, Senefeld JW, et al. Convalescent Plasma Antibody Levels and the Risk of Death from Covid-19. N Engl J Med 2021, published 13 January. Full-text:

Patients who have not yet received mechanical ventilation may benefit from transfusion of plasma with high anti–SARS-CoV-2 IgG antibody levels. However, in this study of 3082 patients there was no effect on the risk of death among patients who had received mechanical ventilation.


Barbui T, Vannucchi AM, Alvarez-Larran A, et al. High mortality rate in COVID-19 patients with myeloproliferative neoplasms after abrupt withdrawal of ruxolitinib. Leukemia (2021). Full-text:

This study found an association between ruxolitinib and overall mortality in 40% of the 45 cases treated with this drug. This effect was due not so much to drug exposure but to its rapid discontinuation (median 0,5 days), that accounted for 75% of deaths. The authors speculate about the reasons for stopping the treatment: uncertainties about possible adverse events? risk of interactions with other drugs? missing interactions between managing physicians and referring hematologist?


Severe COVID

Downar J, Kekewich M. Improving family access to dying patients during the COVID-19 pandemic. Lancet Respir Med 2021, published 12 January. Full-text:

James Downar and Mike Kekewich propose elements of an end-of-life visitor policy: 1) Visitors (up to 4, according to the size of the room) should be allowed during normal visiting hours, 2) preferably 1 h at a time, and 3) when physical circumstances allow, one family member can remain with the patient outside of these hours. 4) Avoid cycling of visitors and 5) make visitors comply with proper infection prevention and control procedures to limit the risks to patients, staff, and to themselves.



Levin Z, Choyke K, Georgiou A, et al. Trends in Pediatric Hospitalizations for Coronavirus Disease 2019. JAMA Pediatr 2021, published 11 January. Full-text:

Between May 15, 2020, and November 15, 2020, there was an increase in hospitalizations among infected children and adolescents in the US. Using data extracted from the University of Minnesota COVID-19 Hospitalization Tracking Project, Pinar Karaca-Mandic, Zachary Levin and colleagues identified 5364 patients aged 19 and under who were hospitalized in 22 US states. The cumulative average rate rose to 17,2 hospitalizations per 100.000 children in November from 2 per 100.000 children in May.



Rubin EJ, Baden LR, Morrissey S. Covid-19 in South Africa and a New SARS-CoV-2 Variant. Audio interview (40:45). N Engl J Med 2021; 384:e14. Access:

The editors discuss Covid-19 in Africa and the impact of a newly discovered SARS-CoV-2 variant.



If you read Spanish, read Sevillano EG, Abril G. Preocupación en la UE por la expansión de la nueva variante de coronavirus. Le País 2021, published 14 January. Full-text:

Alemania se prepara para extender el confinamiento más allá de enero ante las “ocho o diez semanas muy duras” de contagios que prevé Merkel.


Naranjo J. África se queda rezagada en la carrera por vacunar a la población. Le País 2021, published 13 January. Full-text:

La falta de recursos para conseguir dosis, los problemas de aceptación y una logística compleja dificultan que el continente alcance la inmunidad de grupo el año próximo.



If you read French, read Cosnard D. Covid-19 : l’analyse des eaux usées annonce un rebond en Ile-de-France. Le Monde 2021, published 14 January. Full-text :

La concentration de virus dans les eaux usées de la région a crû d’environ 50 % en trois semaines, montrent les prélèvements effectués par le réseau Obépine.



If you read German, read Erdmann E, Schumann F. Jagd auf die mutierten Coronaviren. Die Zeit 2021, published 14 January. Full-text:

Neue Corona-Varianten haben Deutschland erreicht. Um rauszufinden, wie verbreitet sie sind, muss das Virenerbgut untersucht werden. Doch wird das ausreichend getan?


Theile G. Auch die Schweiz nimmt Corona jetzt ernst. Der Spiegel 2021, published 14 January. Full-text:

Der Sonderweg ist teilweise zu Ende: Britische Urlauber haben die hochansteckende Virusvariante ins Land gebracht – nun verkündet die Schweizer Regierung einen härteren Shutdown. Skipisten bleiben aber auf. (Sono pazzi!, Ed.)


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