A virologist studying the novel coronavirus enters the lab at the Szentgothai Research Center of Pecs University in Hungary on 13 May 2020.

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The top coronavirus research articles by metrics

A snapshot of the latest publication metrics and the research articles gaining most attention.

Nature Index

15 May 2020

COVID-19 is not just a global pandemic but also a research publishing phenomenon.

Not since the height of the AIDS epidemic in the 1990s have scientists and the medical profession joined forces on a single topic in this way. With so many people's lives directly affected, research has become news as perhaps never before.

Here we look at two key research metrics in relation to the pandemic: citations in the academic literature, and Altmetric score based on the attention an article attracts in online news and social media.

Until recently, a 2014 Scientific American article on diversity had the highest Altmetric score of all time. That article’s Altmetric score accumulated over six years is 12,077.

The top COVID-19 study by Altmetric score, which investigated the origins of the virus and directly addressed speculation that it was deliberately synthesised in a lab in China, has a score of more than 34,000.

Each of the top five studies related to COVID-19 by Altmetric score, with their scores in the badges listed below, has an Altmetric score of at least 17,000, including one published just two weeks ago.

The top five COVID-19-related studies by citations, also listed below, and also drawn from the Dimensions by Digital Science COVID-19 app, have accumulated thousands of citations in a matter of months.

Interestingly, there is no crossover between the five most popular articles by Altmetric score and the top five by citations, suggesting a divergence in interests between research scientists and those who are primarily engaging with the topic through the media.

While social media and online news audiences are most drawn to research on the origin and spread of the virus, four out of five of the most-cited articles are reports on the symptoms, treatment, and outcomes of the earliest patients in Wuhan, and the other one concerns early transmission of the disease in Wuhan.

All five are among the earliest, if not the earliest, published studies on the virus, which their citations indicate have become foundational works in the burgeoning Sars-CoV-2/COVID-19 literature.

Top 5 papers by citations

1. "Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China"

The Lancet

Amassing more than 2,400 citations since being published on 24 January 2020, this Lancet paper provided an early look at the symptoms, treatment, and clinical outcomes of the first 41 COVID-19 patients admitted to hospital in Wuhan, China between 16 December 2019 and 2 January 2020.

Led by Huang Chaolin, vice president and chief physician of Jinyintan Hospital in Wuhan, the study found that 27 of the 41 patients had been exposed the virus at the Huanan seafood market, and all had pneumonia with “abnormal findings” on chest CT scans.

The study not only continues to be cited regularly, but has an impressive Altmetric score of 14,402, having been covered by 501 news outlets so far and reaching almost 29 million people on Twitter.

2. "A Novel Coronavirus from Patients with Pneumonia in China, 2019"

New England Journal of Medicine

On 31 December 2019, the Chinese Center for Disease Control and Prevention (China CDC) dispatched a rapid response team to collaborate with the Hubei provincial and Wuhan city health authorities to investigate the origins and spread of what was then referred to as a novel coronavirus.

This paper, led by Na Zhu from the National Institute for Viral Disease Control and Prevention at the China CDC, reported the results of the investigation, which provided strong evidence that it was responsible for an outbreak of pneumonia cases in Wuhan.

Since being published on February 20, the paper has earned an Altmetric score of almost 5,000, which is much lower than the most-cited paper, mentioned above. It’s been mentioned by 93 news outlets and has reached almost 18 million people on Twitter.

3. "Clinical Characteristics of 138 Hospitalized Patients with 2019 Novel Coronavirus–Infected Pneumonia in Wuhan, China"

The Journal of the American Medical Association

In February, researchers at the Zhongnan Hospital of Wuhan University in China published a detailed report on coronavirus symptoms and transmission in 138 patients admitted to the hospital in January.

The study, led by Dawei Wang from the hospital’s Department of Critical Care Medicine, revealed that coronavirus patients experience symptoms such as a dry cough, fever, fatigue, muscle pain, and breathing difficulties. It also found that 41% of the study patients had become infected with the SARS-CoV-2 virus while in hospital, with 26% requiring intensive care and 3.4% dying.

Since its publication, the paper has been mentioned by 238 news outlets and 6,269 twitter users, reaching an estimated 20 million people on the platform.

4. "Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study"

The Lancet

A study on 99 coronavirus patients who were admitted to Wuhan Jinyintan Hospital in China in January found that three-quarters had also contracted pneumonia.

Led by Nanshan Chen, chief physician in the respiratory department at the hospital, the study also reported that 17% of coronavirus patients developed fluid in their lungs and 11% died of multiple organ failure. Roughly half of the patients in the study had pre-existing chronic conditions, such as cardiovascular and respiratory diseases.

To date, the paper has mentioned by 210 news outlets, more than 3,408 twitter users and 28 blogs since it was published on 30 January.

5. "Clinical Characteristics of Coronavirus Disease 2019 in China"

New England Journal of Medicine

Collating early patient data is crucial in the early stages of an epidemic or pandemic, and this paper, published on 30 April, builds on earlier studies recording symptoms, affected demographics, treatment and clinical outcomes.

Led by Wei-Jie Guan from the State Key Laboratory of Respiratory Disease at Guangzhou Medical University, China, the study gathered data on 1,099 patients diagnosed with COVID-19 at 552 hospitals across China between 11 December 2019 and 29 January 2020.

The conclusion makes it plain why it is so difficult to control the spread of COVID-19. “During the first 2 months of the current outbreak, COVID-19 spread rapidly throughout China and caused varying degrees of illness,” the authors state. “Patients often presented without fever, and many did not have abnormal radiologic findings.”

The study, which has amassed more than 1,000 citations in just 2 weeks, also has a high Altmetric score of 10,376.

Top five papers by Altmetric score

1. "The proximal origin of SARS-CoV-2"

Nature Medicine

Controversy continues regarding the origin of COVID-19, fuelled by statements from US President Donald Trump, who said at a White House event on 30 April that he had seen evidence that the virus originated in a laboratory in Wuhan, China.

This Nature Medicine paper, led by Kristian G. Andersen, an immunologist at the Scripps Research Institute in California, and published on 17 March, reviewed the genomic data and concluded that it is "not a laboratory construct or a purposefully manipulated virus".

The paper has the highest Altmetric score of all COVID-19-related papers published since January 2020, bolstered by its viral reception on social media. To date, 74,087 Twitter users have tweeted about the study, reaching more than 25 million others on the platform. More than 500 news outlets covered the paper, and it's been referenced by 8 Wikipedia pages so far.

“The discussion is basically over," Andersen told Vanity Fair on May 8.

2. "Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1"

New England Journal of Medicine

When an infected person coughs — or even speaks — they expel tiny droplets known as aerosols into the air, which carry the Sars-CoV-2 virus (the cause of COVID-19). While the larger droplets tend to land on nearby surfaces, smaller ones can remain suspended in the air for hours, posing an infection risk.

This New England Journal of Medicine study, led by virologist Neeltje van Doremalen and colleagues at the US National Institute of Allergy and Infectious Diseases, analysed the stability of SARS-CoV-2 in aerosols and on various surfaces. They found that, under the right conditions, "the virus can remain viable and infectious in aerosols for hours and on surfaces up to days".

According to Altmetric, since being published on April 16, the paper has been picked up by 820 news outlets and more than 22,000 tweeters, reaching almost 24 million Twitter users. It's been referenced by 3 Wikipedia pages to date.

A preprint of the paper, posted on medRxiv on March 13, also has a high Altmetric score of 11,388.

3. "COVID-19 Antibody Seroprevalence in Santa Clara County, California"

medRxiv (preprint)

A controversial preprint has earned the third-highest Altmetric score among COVID-19-related papers published since January 2020.

Led by Eran Bendavid, an infectious diseases physician and an assistant professor of medicine at Stanford University, the study analysed samples from 3,300 volunteers in Santa Clara County, California to measure the prevalence of SARS-CoV-2 antibodies, which could indicate prior infection.

The results found that one in every 66 people had been infected with SARS-CoV-2.

“On the basis of that finding, the researchers estimate that between 48,000 and 82,000 of the county’s roughly 2 million inhabitants were infected with the virus at that time — numbers that contrast sharply with the official case count of some 1,000 people reported in early April,” Smriti Mallapaty reported for Nature.

The paper, which was published on April 30 and has yet to be formally peer-reviewed, has drawn strong criticism for its methodology, including from Trevor Bedford from the Department of Epidemiology at the University of Washington, who said on Twitter that he remains “sceptical” of the results.

The preprint has been tweeted by 30,467 people, reaching almost 38 million people on Twitter, according to Altmetric, and has been covered by 415 news outlets.

4. "Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period"

Science

Led by Stephen Kissler from the Department of Immunology and Infectious Diseases at the Harvard T.H. Chan School of Public Health, this much-discussed study sought to understand future transmission trends of the SARS-CoV-2 virus across the United States over the next five years.

The results, published in Science on April 14, predict that recurrent outbreaks will follow the current pandemic wave. The authors suggest that “prolonged or intermittent social distancing may be necessary into 2022”.

The study has been covered by 544 news outlets and more than 27,000 Twitter users, and Altmetric has estimated a reach on Twitter of almost 37 million.

More recently, Kissler and his team used postal code and location data from Facebook to find a link between New York neighbourhood infection rates and the number of daily trips taken by its residents.

5. "Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-CoV-2)"

Science

Roughly 86% of COVID-19 cases were undocumented before travel restrictions were put in place in Wuhan, China on 23 January 2020, according to this Science paper published on May 1, which sought to investigate how the virus managed to spread around the world in a period of three to four months.

Led by Ruiyun Li from the Department of Infectious Disease Epidemiology at Imperial College London, the study indicates that “containment of this virus will be particularly challenging”.

The authors, based in the United Kingdom, the US, China, and Hong Kong, conclude that a “radical increase” in the identification and management of currently undocumented infections is needed to fully control the spread of the virus.

As Jane Qiu writes for Nature, the undocumented cases Li’s group investigated include “those that are missed because authorities aren’t doing enough testing, or ‘preclinical cases’ in which people are incubating the virus but not yet showing symptoms”.

According to Altmetric, the study has been picked up by 360 news outlets so far, and more than 21,000 tweeters, reaching an estimated 37 million people across the platform.

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