Authors: Heather Jones, Future Science Group
This month’s top COVID-19 research articles include several studies citing the benefits of facemasks, as well as research investigating adaptive immunity to SARS-CoV-2 and a genome-wide study exploring COVID-19 severity.
In last month’s research round-up, we summarized a study published in the Lancet regarding a trial of hydroxychloroquine and chloroquine. The study authors have since retracted this article, as they were unable to complete an independent third-party peer review of the corporation responsible for the trial.
A randomized trial of hydroxychloroquine as post-exposure prophylaxis for COVID-19
Boulware et al., 2020 – N. Engl. J. Med.
A randomized placebo-controlled trial was conducted across the US and parts of Canada testing hydroxychloroquine as post-exposure prophylaxis. This involved adults who had been exposed to someone with COVID-19 being administered either hydroxychloroquine or a placebo within 4 days after exposure. The researchers observed no significant difference in the incidence of new illness compatible with COVID-19 among the participants, concluding that hydroxychloroquine did not prevent the onset of COVID-19 in this instance.
Identifying airborne transmission as the dominant route for the spread of COVID-19
Zhang et al., 2020 – PNAS
Although widely adopted social distancing and mandatory face coving have been implemented among other mitigation measures against the spread of SARS-CoV-2, the understanding of virus transmission remains uncertain. In order to improve our understanding of the route of transmission, researchers analyzed the trends associated with mitigation measures in Wuhan (China), Italy and New York City (USA). From the analysis, they concluded that mandatory use of face coverings influenced the pandemic trends in three epicenters by significantly reducing the number of infections, highlighting the importance of this practise alongside social distancing, quarantine and contact tracing.
Targets of T Cell responses to SARS-CoV-2 coronavirus in humans with COVID-19 disease and unexposed individuals
Grifoni et al., 2020 – Cell
In efforts to further our understanding of adaptive immunity to SARS-CoV-2, researchers used HLA class I and II predicted peptide “megapools” to identify circulating SARS-CoV-2 specific CD8+ and CD4+ T cells in COVID-19 convalescent patients. The results of the study reveal CD8+ and CD4+ T cells to be present in approximately 70% and 100% of patients, respectively. The researchers also discovered SARS-CoV-2-reactive CD4+ T cells in approximately 40–60% of unexposed individuals, suggesting cross-reactive T cell recognition between other circulating coronaviruses and SARS-CoV-2.
Compassionate use of remdesivir for patients with severe COVID-19
Grein et al., 2020 – N. Engl. J. Med.
In yet another trial of remdesivir, the authors describe the outcomes in a cohort of patients hospitalized with severe COVID-19 who were treated with the drug on a compassionate-use basis. Overall, they observed clinical improvement in 68% of the patients involved in the trial, and suggested the need for ongoing randomized, placebo-controlled trials of the therapy in order to measure its efficacy.
A modelling framework to assess the likely effectiveness of face masks in combination with ‘lock-down’ in managing the COVID-19 pandemic
Stutt et al., 2020 – Proc. R. Soc. Lond.
The last couple of months has seen an increase in the mandatory use of face masks in public across several countries, alongside a growing body of evidence citing its value in the fight against the pandemic. A recent paper published by the Proceedings of the Royal Society describes the results of two mathematical models to examine the dynamics of COVID-19 epidemics when face masks are worn by the public, with or without imposed ‘lock-down’ periods. The researchers revealed that when face masks are used by the public at all times, the effective reproduction number can be decreased below 1. The spread of disease is further reduced upon the addition of lockdown measures. These analyses may explain why some countries, where face masks are used by the public all the time, have experienced significantly lower rates of COVID-19 spread.
No evidence of rapid antiviral clearance or clinical benefit with the combination of hydroxychloroquine and azithromycin in patients with severe COVID-19 infection
Molina et al., 2020 – Med. Maladies Infect.
In a recent letter to the editor, a group of researchers responded to a paper published in March that reported benefits associated with hydroxychloroquine and azithromycin treatment. The authors of the letter outlined their observations of the use of these treatments in their own department, concluding that they found no evidence of a strong antiviral activity or clinical benefit of the drug combination for the treatment of their hospitalized patients.
Genome-wide association study of severe COVID-19 with respiratory failure
Ellinghaus et al., 2020 – N. Engl. J. Med.
Given the considerable variation in disease presentation among COVID-19 patients, researchers performed a genome-wide association study of 1980 COVID-19 patients with respiratory failure at seven hospitals across the disease epicenters of Italy and Spain. Upon analysis, they identified a specific gene cluster that could be a cause of genetic susceptibility to the virus in those with COVID-19-induced respiratory failure. They also reported a potential involvement of the ABO blood group system in the level of risk associated with SARS-CoV-2 infection.
A systematic review and meta-analysis published in the Lancet was conducted in order to investigate the optimum distance for avoiding person–person virus transmission and to assess the possible benefits of face masks and eye protection. This involved the analysis of data from 172 observational studies and 44 relevant comparative studies. The researchers concluded that their investigation supported physical distancing of 1 metre or more and suggest that their results inform the optimum use of facemasks, respirators and eye protection in public and healthcare settings while awaiting the results of robust randomized trials to further support these interventions.
Estimating the effects of non-pharmaceutical interventions on COVID-19 in Europe
Flaxman et al., 2020 – Nature
Following the large epidemics experienced across Europe, a team of researchers studied the impact of major non-pharmaceutical interventions in 11 European countries before lockdown measures were eased. While acknowledging the large number of factors influencing their results, including incomplete data and biases in reporting, the researchers concluded that, for the 11 countries considered in the study, the systematic measures put in place were sufficient to drive the reproduction number below 1, and have therefore been highly influential in reducing virus transmission. Further, they were able to estimate that 3.2–4.0% of the population across all 11 countries has been infected with SARS-CoV-2 up to 4 May.