By Jia You

Genomicist Neil Hall sparked an on-

line tempest this summer by pro-

posing a “Kardashian Index,” or

K-index—a comparison of a scien-

tist’s number of Twitter followers

with their citations. Scientists with

a high score on the index, named after the

reality TV star Kim Kardashian, one of the

most popular celebrities on the social me-

dia platform, should “get off Twitter” and

write more papers, suggested Hall, who

works at the University of Liverpool in the

United Kingdom.

Though Hall says he meant his K-index

lightheartedly, his article in Genome Biol-

ogy sparked a Twitter storm of criticism.

So just who are the Kardashians of science,

and is Hall’s criticism justified? Hall tact-

fully declined to provide a K-index for any-

one specific, but Science was curious about

the names and the numbers. We have

compiled a list of the 50 most followed sci-

entists on the social media platform and

their academic citation counts—and calcu-

lated their K-index.

Rather than identifying “Science

Kardashians”—those who are, as Hall put

it, “famous for being famous”—the list

reveals that a majority of science Twitter

stars spend much, if not all, of their time

on science communication. For them,

Twitter popularity can amplify their efforts

in public outreach. A case in point is Neil

deGrasse Tyson, director of the Hayden

Planetarium in New York City and host of

the science TV show Cosmos: A Spacetime

Odyssey. With more than 2.4 million fol-

lowers and fewer than 200 citations, the

astrophysicist is the top-ranking celebrity

scientist on Twitter—and has the highest

K-index of anyone on the list. Yet few would

consider his Twitter fame unwarranted.

Although the index is named for a

woman, Science’s survey highlights the

poor representation of female scientists

on Twitter, which Hall hinted at in his

commentary. Of the 50 most followed sci-

entists, only four are women. Astronomer

Pamela Gay of Southern Illinois Univer-

sity, Edwardsville, whose more than 17,000

Twitter followers put her 33rd on the list,

says that doesn’t surprise her because so-

ciety still struggles to recognize women as

leaders in science. Female scientists are

also more likely to face sexist attacks on-

line, she adds. “At some point, you just get

fed up with all the ‘why you are ugly’ or

‘why you are hot’ comments.”

Twitter stardom need not exclude re-

search achievements, as our top 50 Twit-

ter list shows. Many have thousands of

citations and seven of the people listed

also appear on two recent citation-based

rankings of influential scientists. (Find an

expanded story, the full top 50 list, and de-

tails on how we compiled the story’s data at

http://scim.ag/Twitterstars.) Even so, most

high-performing scientists have not em-

braced Twitter. Science sampled Twitter

usage among 50 randomly chosen living

scientists from Scholarometer’s top 100

authors ranking. Only a fifth of the scien-

tists have an identifiable Twitter profile.

Even some who do dislike the medium.

Chad Mirkin of Northwestern University

in Evanston, Illinois, the highest ranking

chemist on Scholarometer’s list, consid-

ers Twitter a waste of precious time that

he’d much prefer spending on reading and

writing scientific papers. “A lot of social

media is … time spent aggrandizing one’s

accomplishment,” says Mirkin, who regis-

tered on Twitter just to keep up with his

son’s tennis scores.

So why do the highly cited researchers

who are also Twitter science stars make

the time to engage in social media? Geneti-

cist Eric Topol of the Scripps Research In-

stitute in San Diego, California (17th place;

44,800 followers), who boasts more than

150,000 citations, says he once thought the

social media platform was only for “silly

stuff” like celebrity news. Then he tried

NEWS | IN DEPTH

1440 19 SEPTEMBER 2014 • VOL 345 ISSUE 6203 sciencemag.org SCIENCE

SCIENTIFIC COMMUNITY

Who are the science stars of Twitter?Science communicators and some highly cited researchers, but few women, make top 50 list

Twitter’s scientific celebrities

The top 20 of the 50 most followed scientists on Twitter

Neil deGrasse Tyson 2,400,000 151 11129 Astrophysicist

Brian Cox 1,440,000 33,301 1188 Physicist

Richard Dawkins 1,020,000 49,631 740 Biologist

Ben Goldacre 341,000 1,086 841 Physician

Phil Plait 320,000 254 1256 Astronomer

Michio Kaku 310,000 5,281 461 Theoretical physicist

Sam Harris 224,000 2,416 428 Neuroscientist

Hans Rosling 180,000 1,703 384 Global health

scientist

Tim Berners-Lee 179,000 51,204 129 Computer scientist

P. Z. Myers 155,000 1,364 355 Biologist

Steven Pinker 142,000 49,933 103 Cognitive scientist

Richard Wiseman 134,000 4,687 207 Psychologist

Lawrence M. Krauss 99,700 10,155 120 Theoretical physicist

Atul Gawande 96,800 13,763 106 Surgeon/public

health scientist

Oliver Sacks 76,300 13,883 83 Neurologist

Dan Ariely 73,000 16,307 76 Psychologist/

behavioral economist

Eric Topol 44,800 151,281 23 Geneticist

Brian Greene 38,700 11,133 45 Theoretical physicist

Marcus du Sautoy 34,200 1,461 77 Mathematician

Sean M. Carroll 33,200 14,208 36 Theoretical physicist

SCIENTIST FOLLOWERS CITATIONS K-INDEX EXPERTISE

Published by AAAS

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Twitter during a TEDMED conference in

2009, as a tool to gauge reactions to his

talk. Now, he starts his workday brows-

ing through his Twitter feed for news and

noteworthy research in his field. During

the day, he checks Twitter several times

and spends another 10 to 20 minutes on

an evening roundup. “It actually may be

the most valuable time [I spend] in terms

of learning things that are going on in the

world of science and medicine,” says Topol,

who reciprocates by daily tweeting papers,

presentations, and more to his followers.

Psychologist Daniel Gilbert of Harvard

University (36th; 15,500 followers) views

Twitter as a natural extension of his public

outreach efforts, which include hosting the

PBS science documentary, This Emotional

Life. “It’s another teaching tool,” he says.

Jonathan Eisen of the University of

California, Davis (25th; 24,900 follow-

ers), says that consistently tweeting on-

going research at his lab has helped attract

graduate students as well as two grants for

science communication. He suggests an

active social media presence might even

aid applications for research funding, as

it demonstrates a commitment to public

outreach. But the spontaneity of Twitter

can backfire, too. Eisen, for one, has live-

tweeted brusque criticism at academic

conferences that came back to bite him.

“You can seem like a jerk, an idiot, or both,”

he says.

The K-index gets it wrong by suggest-

ing that science communication and re-

search productivity are incompatible, says

Albert-László Barabási, a network theo-

rist at Northeastern University in Boston

who studies social media. Research on

altmetrics—alternative metrics for mea-

suring scientific impact—has found no

link between social media metrics such as

number of tweets and traditional impact

metrics such as citations, he says. “We

should really not mix the two … because

they really probe different aspects of a sci-

entist’s personality.”

For his part, Hall says others have read

too much into his satire, which originated

after seeing conference organizers factor

Twitter follower numbers into speaker con-

siderations. “I don’t mean to criticize any-

one for having a lot of Twitter followers,”

he says. “My criticism is only of using it as

a metric on research scientists.”

It might be premature, in any case, for

the scientific community to worry about

“Science Kardashians” when it faces a

more pressing challenge of staying rel-

evant in public discussions. Even Tyson’s

Twitter popularity is dwarfed by that of the

real Kim Kardashian, who boasts 10 times

as many followers. ■

By Jon Cohen

As the Ebola outbreak in West Africa

accelerates, the containment measures

that worked in the past, such as isolat-

ing those who are infected and tracing

their contacts, clearly have failed. This

has spurred hopes that biomedical

countermeasures, such as monoclonal anti-

bodies and vaccines, can help save lives and

slow spread. But as President Barack Obama

calls for an aggressive ramp up of the U.S.

government’s response (see p. 1434), resolve

is colliding with a grim reality: The epidemic

is outpacing the speed with which drugs and

vaccines can be produced.

Administration officials have begun work-

ing with industry to speed manufacturing of

experimental drugs and vaccines. “We’re try-

ing to do everything we can to scale up prod-

uct,” says Nicole Lurie, assistant secretary

for preparedness and response at the U.S.

Department of Health and Human Services

(HHS). But the logistical obstacles are huge,

and makers are getting a late start.

An Ebola vaccine made by GlaxoSmith-

Kline (GSK) in Rixensart, Belgium, is the fur-

thest along, having entered phase I human

trials on 2 September. GSK has committed

to manufacturing up to 10,000 doses of the

vaccine, which consists of an Ebola surface

protein stitched into a weakened chimpan-

zee adenovirus, by the end of the year. If it

passes muster in the early studies, it could

be given to health workers as soon as No-

vember. But hundreds of thousands of doses

would be needed to slow the outbreak. That

“would take one-and-a-half years at the scale

we’re working at,” says Ripley Ballou, who

heads the Ebola vaccine program for GSK.

The scientific hurdles are not particularly

high. Companies have made similar vac-

cines at high volume, and animal studies

have shown that Ebola virus is fairly easy

to defeat with the proper immune response.

“Although Ebola is a very scary, hemorrhagic

virus, all you need is fairly modest neutraliz-

ing antibody response and you’re protected,”

says John Eldridge, chief scientific officer at

Profectus BioSciences, a Maryland and New

York–based company making an Ebola vac-

cine that has struggled to attract funding.

Ballou says GSK is considering several

options for speeding production. But first

the company wants to be sure that there’s

a market for the vaccine. He says when the

company contacted the World Health Or-

ganization at the start of this outbreak in

March, no one showed much interest. “The

answer was, ‘Thanks, we’ll get back to you.’ ”

NewLink Genetics of Ames, Iowa, has a

second vaccine in a phase I trial that con-

sists of a crippled vesicular stomatitis virus

(VSV), which infects livestock, with the gene

for the Ebola virus surface protein. Only

1500 doses exist. Profectus makes a similar

vaccine that should be ready for human test-

ing next June. Like GSK, Profectus needs

a commitment from a funder before it can

scale up production from the planned 5000

to 20,000 doses, Eldridge says.

In principle, vaccine production is

Ebola vaccine: Little and late Scaling up production of Ebola vaccines and treatments will take many months

INFECTIOUS DISEASE

Okairos uses a

“wave bag” to shake up cells

and produce small lots of vaccine.

Published by AAAS