Copy-editor: Rob Camp
Vaccine
Paper of the Day
Levine-Tiefenbrun M, Yelin I, Katz R, et al. Decreased SARS-CoV-2 viral load following vaccination. MedRxiv 2021, posted 8 February. Full-text: https://www.medrxiv.org/content/10.1101/2021.02.06.21251283v1
Roy Kishony, Matan Levine-Tiefenbrun and colleagues analyzed positive SARS-CoV-2 test results following the first shot of the Pfizer-BioNTech vaccine. They found that the viral load is reduced 4-fold for infections occurring 12-28 days after the first dose of vaccine. These reduced viral loads might hint to lower infectiousness, further contributing to vaccine impact on virus spread.
Xie X, Liu Y, Liu J, et al. Neutralization of SARS-CoV-2 spike 69/70 deletion, E484K and N501Y variants by BNT162b2 vaccine-elicited sera. Nat Med 2021, published 8 February. Full-text: https://www.nature.com/articles/s41591-021-01270-4
In this in vitro study, the neutralization GMT of the serum panel against a virus with three mutations from the variant first detected in South Africa (E484K + N501Y + D614G) was slightly lower than the neutralization GMTs against a N501Y virus or a virus with three mutations from the UK variant (Δ69/70 + N501Y + D614G). The authors tested a panel of human sera from 20 participants in the Pfizer-BioNTech vaccine trial, drawn 2 or 4 weeks after immunization with two 30-μg doses of Comirnaty spaced 3 weeks apart.
Variants
Althaus C, et al. Transmission of SARS-CoV-2 variants in Switzerland. Institute of Social and Preventive Medicine (ISPM), University of Bern 2021, reported 5 February. Full-text: https://ispmbern.github.io/covid-19/variants/
For 5 February, the authors estimated the proportion of SARS-CoV-2 variants (501Y, B.1.1.7) to have reached 67% in Geneva and 35% in Zurich. They also estimated the increase in transmissibility slightly above 50%.
Epidemiology
Davies N, Abbott S, Barnard C, et al. Estimated transmissibility and severity of novel SARS-CoV-2 Variant of Concern 202012/01 in England. CMMID Repository 2021, updated 6 February. Full-text: https://cmmid.github.io/topics/covid19/uk-novel-variant.html?s=09
The authors estimate that B117 is 43–82% (range of 95% credible intervals 38–106%) more transmissible than pre-existing variants of SARS-CoV-2. We find that without stringent control measures, COVID-19 hospitalizations and deaths are projected to reach higher levels in 2021 than were observed in 2020. Control measures of a similar stringency to the national lockdown implemented in England in November 2020 would be unlikely to reduce the effective reproduction number Rt to less than 1, unless primary schools, secondary schools, and universities are also closed.
Virology
Ozono S, Zhang Y, Ode H, et al. SARS-CoV-2 D614G spike mutation increases entry efficiency with enhanced ACE2-binding affinity. Nat Commun 12, 848 (2021). Full-text: https://www.nature.com/articles/s41467-021-21118-2
The D614G mutation increases cell entry by acquiring higher affinity to ACE2. The mutation does not affect neutralization by antisera against prototypic viruses.
Immunology
Hoagland DA, Møller R, Uhl SA. Leveraging the antiviral type-I interferon system as a first line defense against SARS-CoV-2 pathogenicity. Immunity 2021, published 29 January. Full-text: https://www.cell.com/immunity/fulltext/S1074-7613(21)00040-6
A longitudinal hamster cohort revealed a wave of inflammation including a Type-I interferon (IFN-I) response that was evident in all tissues regardless of viral presence but was insufficient to prevent disease progression. Bolstering the antiviral response with intranasal administration of recombinant IFN-I reduced viral disease, prevented transmission, and lowered inflammation in vivo. The authors conclude that intranasal IFN-I might be an effective means of early treatment.
Valenzuela Nieto G, Jara R, Watterson D, et al. Potent neutralization of clinical isolates of SARS-CoV-2 D614 and G614 variants by a monomeric, sub-nanomolar affinity nanobody. Sci Rep 11, 3318 (2021). Full-text: https://www.nature.com/articles/s41598-021-82833-w
The authors describe a novel simple method for the selection of nanobodies from E. coli bacterial display libraries, resulting in the selection of 30 nanobodies. They demonstrate that the nanobody W25 can recognize full-length Spike and RBD protein by ELISA and therefore predict that it might be suitable as a diagnostic reagent.
Long COVID
Raven K. Long-COVID – the nightmare that won’t end – a researcher’s first hand perspective. Peacock Lab 2021, published 6 February. Full-text: https://professorsharonpeacock.co.uk/long-covid-the-nightmare-that-wont-end-a-first-hand-perspective
“I’ve given an account of my own experience with long COVID, which I hope will help to raise awareness of this debilitating illness, but it’s estimated there could be 300.000 other sufferers in the UK (3), with more joining those ranks every day. Some features are shared with others, others differ. But I think for all of us recognition, help, and research are key. And we need them desperately.”