The 5 most popular scientific papers of January 2021 in the Nature Index journals

A new approach to MS treatment based on COVID-19 vaccine tech and a sobering look at the fate of sharks and rays feature in these widely-discussed studies

  • Bec Crew

Mobula rays seen from the air swimming in Nopapu, Vava, Tonga.
Credit: Steve Woods Photography/Getty Images

The 5 most popular scientific papers of January 2021 in the Nature Index journals

A new approach to MS treatment based on COVID-19 vaccine tech and a sobering look at the fate of sharks and rays feature in these widely-discussed studies.

20 April 2021

Bec Crew

Steve Woods Photography/Getty Images

Mobula rays seen from the air swimming in Nopapu, Vava, Tonga.

January’s most talked-about natural-sciences papers highlight evolving knowledge about COVID-19 and its impacts more than a year since the first signs of it appeared in Wuhan, China in late 2019.

Also described in this list are the results of a study on sharks and rays – a group that has declined dramatically over the past few decades due to overfishing.

Here is an Altmetric ranking of January’s most popular papers in the natural sciences, published in the 82 high-quality journals tracked by the Nature Index.

1. “Immunological memory to SARS-CoV-2 assessed for up to 8 months after infection”


According to this study, led by researchers at the La Jolla Institute for Immunology Center for Infectious Disease and Vaccine Research (LJI) in California, COVID-19 survivors appear to carry protective immunity against the SARS-CoV-2 virus for at least eight months after the initial infection.

The finding is based on 254 samples from 188 COVID-19 cases across the United States, including 43 samples at six to eight months after infection. The majority of the cases were mild, but symptomatic.

Four major types of immune memory were tracked over an eight-month period after infection.

Virus-specific antibodies were found to persist in the bloodstream for months, declining moderately during this period. Memory B cells, a type of B lymphocyte known to circulate in the blood stream for many years after a viral infection, increased between one and eight months after infection.

Memory CD8+ T cells and memory CD4+ T cells were found to decline over the same period, but like the antibodies, were retained in large enough amounts to provide some level of protection against reinfection.

"The immune response decreases over time to a certain extent, but that's normal,” said Alessandro Sette from the LJI, who co-led the study with colleagues Shane Crotty and Daniela Weiskopf.

The paper has been covered by more than 300 online news outlets to date, and reached an estimated audience on Twitter of more than 28 million.

2. “A noninflammatory mRNA vaccine for treatment of experimental autoimmune encephalomyelitis”


Messenger RNA (mRNA) vaccines rose to prominence in 2020 in response to the COVID-19 pandemic. They work by delivering snippets of RNA that code for coronavirus proteins, which prompts the body to mount an immune response.

One of the most widely distributed COVID-19 vaccinations is an mRNA vaccine produced by pharmaceutical companies Pfizer in New York City and BioNTech in Mainz, Germany.

Researchers from BioNTech are part of the team behind this widely discussed Science paper, which explores the potential of using mRNA vaccines as a new treatment for multiple sclerosis (MS) and similar conditions.

In patients with MS, immune cells enter the brain and spinal cord and break down the fatty protein that insulates the nerve cells, called myelin, as well as the cells that produce myelin.

MS and other autoimmune diseases can be very difficult to treat. Patients differ greatly in terms of the presentation, duration and progression of the symptoms, and rarely respond to treatment, which can involve a combination of medication, physical and occupational therapy, exercise and rest, in the same way.

This paper describes a different approach. Researchers in Germany injected mRNA into mice with an MS-like condition. The mRNA were engineered to instruct certain cells to produce a myelin-like substance in a way that is tolerated by the immune system, rather than attacked by it.

The treatment was found to delay the onset and reduced the severity of the MS-like disease in mice without showing symptoms of immune suppression.

The paper has been covered by 50 online news outlets to date, and reached an estimated audience on Twitter roughly 30 million. Audiences in the United States were the most highly engaged, according to Altmetric.

3. “Evolution of antibody immunity to SARS-CoV-2”


The SARS-CoV-2 virus, which causes COVID-19, is mutating. Variants such as D614G, a mutation in the spike protein of SARS-CoV-2, which helps the virus particles to penetrate cells, have been closely monitored by researchers since last year, because they have the potential to make the virus more transmissible.

D614G has quickly become the dominant variant in the global COVID-19 pandemic. Researchers and healthcare providers are investigating whether the antibodies produced in people who have been infected with or vaccinated against this variant can impart some level of protection against future viral variants.

As explained in a later Nature report, antibody-producing B-cells can evolve through natural selection to make antibodies that bind more tightly to their target, a process known as maturation.

This paper, with Christian Gaebler from the Laboratory of Molecular Immunology at the Rockefeller University in New York as lead author, found that 83% of these ‘mature’ antibodies showed an increased rate of recognizing and binding to proteins from new SARS-CoV-2 variants.

The paper has been covered by 171 news outlets to date, and has reached an audience on Twitter of more than 15 million. Its findings along with other studies’ have been interpreted as suggesting that vaccines might be effective against past and future coronavirus variants.

“Getting vaccines that will tackle the variants that are currently circulating is an eminently solvable problem,” Paul Bieniasz, co-author and virologist at the Rockefeller University, whose laboratory is studying variants, told Nature. “It might be that we already have that solution.”

4. “Half a century of global decline in oceanic sharks and rays”


Since 1970, open-ocean shark and ray populations have shrunk by 71 percent. According to this study, with Nathan Pacoureau from the Earth to Ocean Research Group at Simon Fraser University in British Columbia, Canada as lead author, this significant decline has resulted from overfishing.

Pacoureau and his colleagues used two biodiversity indicators for oceanic sharks and rays based on data tracking species’ population changes and relative extinction risk.

They estimated, for example, that in 1980, two-thirds of oceanic shark species fell into the International Union for Conservation of Nature Red List of Threatened Species category of least concern, and only nine were threatened. The basking shark (Cetorhinus maximus) was the only species that was retrospectively classified as endangered.

Today, more than three-quarters of these species are threatened, based on steep population reductions, the study reports, listing the oceanic whitetip shark (Carcharhinus longimanus), scalloped hammerhead (Sphyrna lewini) and great hammerhead (Sphyrna mokarran) as critically endangered.

The results are sobering enough, but may not reflect the full reality, according to David Sims, professor of marine ecology at the University of Southampton, UK, who was not involved in the study.

“It’s particularly worrying that unreported catches weren’t included in the study’s analyses,” Sims writes for The Conversation. “This means the number of sharks and rays killed by fishing boats is likely to be an underestimate and the actual declines of these species may be even worse.”

The paper has been covered by 307 online news outlets to date, and reached an estimated audience on Twitter of more than 7 million.

5. “Neuroinvasion of SARS-CoV-2 in human and mouse brain”

The Journal of Experimental Medicine

The possibility that the SARS-CoV-2 virus can penetrate the brain is a topic of urgent focus for researchers.

This paper, with Eric Song from the Department of Immunobiology at the Yale School of Medicine in New Haven, Connecticut as lead author, used mouse brain tissue and human brain organoids – miniature brains, the size of sesame seeds, grown from human stem cells – to provide evidence that the virus can directly infect the central nervous system and replicate, a finding consistent with other recent high-profile papers.

The team also analyzed autopsies and brain samples from three patients who had died of COVID-19 and detected SARS-CoV-2 in the neurons of one of them.

One of the authors, Akiko Iwasaki, a professor of immunobiology and molecular, cellular and developmental biology at Yale School of Medicine, said future studies are needed to investigate what might predispose some patients to infections of the central nervous system, and “the route of SARS-CoV-2 invasion into the brain and the sequence of infection in different cell types within the central nervous system”.

The paper has been mentioned by 30 news outlets to date and has reached an audience on Twitter of roughly 10 million.