Copy-editor: Rob Camp
Paper of the Day
Garcia-Beltran WF, Lam EC, St. Denis K, et al. Circulating SARS-CoV-2 variants escape neutralization by vaccine-induced humoral immunity. medRxiv 2021, posted 18 February. Full-text: https://doi.org/10.1101/2021.02.14.21251704
While many strains, such as B.1.1.7, B.1.1.298, or B.1.429, continue to be potently neutralized despite the presence of individual receptor-binding domain (RBD) mutations, other circulating SARS-CoV-2 variants escape vaccine-induced humoral immunity. The P.2 variant, which contains an E484K mutation within the RBD region, was capable of significantly reducing the neutralization potency of fully vaccinated individuals. Similarly, the P.1 strain, which has three RBD mutations, more effectively escaped neutralization. Finally, B.1.351 variants exhibited remarkable resistance to neutralization, largely due to three mutations in RBD but with a measurable contribution from non-RBD mutations. The magnitude of the effect is such that B.1.351 strains escape neutralizing vaccine responses like SARS-CoV-1 (SARS 2002/2003) and bat-derived WIV1-CoV, suggesting that a relatively small number of mutations can mediate potent escape from vaccine responses. Alejandro Balazs, Wilfredo F. Garcia-Beltran and colleagues emphasize the need to develop broadly protective interventions against the evolving pandemic.
Resende PC, Delatorre D, Gräf T, et al. Evolutionary Dynamics and Dissemination Pattern of the SARS-CoV-2 Lineage B.1.1.33 During the Early Pandemic Phase in Brazil. Front. Microbiol 2021, 17 February. Full-text: https://www.frontiersin.org/articles/10.3389/fmicb.2020.615280/
Paula Cristina Resende et al. investigated the origin of the major and most widely disseminated SARS-CoV-2 Brazilian lineage B.1.1.33 that evolved from an ancestral clade, here designated B.1.1.33-like. The B.1.1.33-like lineage may have been introduced from Europe or may have arisen in Brazil in early February 2020 and a few weeks later gave origin to the lineage B.1.1.33.
Kistler KE, Bedford T. Evidence for adaptive evolution in the receptor-binding domain of seasonal coronaviruses OC43 and 229e. Elife. 2021 Jan 19;10:e64509. PubMed: https://pubmed.gov/33463525. Full-text: https://doi.org/10.7554/eLife.64509
Kathryn Kistler and Trevor Bedford provide evidence that at least two of the seasonal coronaviruses, OC43 and 229E, are undergoing adaptive evolution in regions of the viral spike protein that are exposed to human humoral immunity. This suggests that reinfection may be due, in part, to positively selected genetic changes in these viruses that enable them to escape recognition by the immune system.
Kissler S, Fauver JR, Mack C, et al. Densely sampled viral trajectories suggest longer duration of acute infection with B.1.1.7 variant relative to non-B.1.1.7 SARS-CoV-2. dash.harvard.edu 2021, accessed 17 February. Full-text: https://dash.harvard.edu/handle/1/37366884
B.1.1.7 may cause longer infections with similar peak viral concentration compared to non-B.1.1.7 variants. This extended duration may contribute to B.1.1.7 SARS CoV-2’s increased transmissibility. Yonatan Grad, Stephen Kissler and colleagues assessed longitudinal PCR tests performed in a cohort of 65 individuals infected with SARS-CoV-2 undergoing daily surveillance testing, including seven infected with B.1.1.7.
|Mean duration of the
(90% credible interval)
|Mean duration of the
|Mean overall duration of infection
(proliferation + clearance phase)
|Peak viral concentration||19,0 Ct
|log10 RNA copies/ml||8,5
Tan ZP, Silwal L, Bhatt SP, et al. Experimental characterization of speech aerosol dispersion dynamics. Sci Rep 11, 3953 (2021). Full-text: https://www.nature.com/articles/s41598-021-83298-7
Relative to sneezing and coughing, non-symptomatic aerosol-producing activities such as speaking are highly understudied. Here, Vrishank Raghav, Zu Puayen Tan and colleagues of Auburn University, US, delve into the details of jet phases and puff phases. One of their conclusions: speaking may represent a higher transmission risk than coughs and sneezes. Sneezing and coughing are singular events with a plume-front that passes by quickly, whereas speaking is a prolonged activity continuously producing plumes of aerosols.
Shriner SA, Ellis JW, Root JJ, Roug A, Stopak SR, Wiscomb GW, et al. SARS-CoV-2 exposure in escaped mink, Utah, USA. Emerg Infect Dis. 2021 Mar. Full-text: https://doi.org/10.3201/eid2703.204444
Free-range mink, presumed domestic escapees, exhibited high antibody titers, suggesting a potential SARS-CoV-2 transmission pathway to native wildlife. Interactions or shared resources between escaped mink and wild mink or other wildlife species represent potential transmission pathways for spillover of SARS-CoV-2 into wildlife and could lead to health consequences or establishment of new reservoirs in susceptible wildlife
Illingworth C, Hamilton W, Warne B, et al. Superspreaders drive the largest outbreaks of hospital onset COVID-19 infection. OSF Preprints 2021, posted 15 February. Full-text: https://osf.io/wmkn3/
Chris Illingworth et al. provides a detailed retrospective analysis of nosocomial SARS-CoV-2 transmission. Their data were consistent with a pattern of superspreading, where 20% of individuals caused 80% of transmission events.
Arnold C. Covid-19: How the lessons of HIV can help end the pandemic. BMJ 2021, published 16 February. Full-text: https://doi.org/10.1136/bmj.n216
Harm reduction, which proved its worth in HIV/AIDS, can help stem the COVID-19 pandemic by helping people change their behavior. Carrie Arnold explains how.
Neeland MR, Bannister S, Clifford V, et al. Innate cell profiles during the acute and convalescent phase of SARS-CoV-2 infection in children. Nat Commun 12, 1084 (2021). Full-text: https://www.nature.com/articles/s41467-021-21414-x
Melanie Neeland et al. provide a comprehensive characterization of innate cells responding during the acute and convalescent phase of mild pediatric COVID-19. The authors report acute and convalescent innate immune responses in 48 children and 70 adults infected with, or exposed to, SARS-CoV-2. The authors found that infection in children is characterized by increased activation of neutrophils and low circulating proportions of all monocyte subsets, dendritic cells and natural killer cells, in contrast to SARS-CoV-2-infected adults who showed reductions in the non-classical monocyte fraction only.
Kupferschmidt K. Unprotected African health workers die as rich countries buy up COVID-19 vaccines. Science 2021, published 17 February. Full-text: https://www.sciencemag.org/news/2021/02/unprotected-african-health-workers-die-rich-countries-buy-covid-19-vaccines
While we are discussing how soon we can immunize everyone in the EU or the US, health workers continue to die in countries with zero doses administered so far.
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