14 | New Scientist | 6 February 2021
News
NEARLY 1 million people are now
taking pre-exposure prophylaxis
(PrEP), drugs that can slash the risk
of HIV infection. While early use
was mostly limited to Western
nations, the number of users
in sub-Saharan Africa (SSA) has
greatly risen, now accounting for
more than half of global users.
Kate Segal at AVAC, a New York-
based non-profit organisation
focused on global HIV prevention,
presented the latest data on PrEP
use at the virtual HIV Research
for Prevention Conference on
26 January. She said there had
been a major expansion of PrEP
users in 2020, with a rise of more
than 300,000 from the previous
year. In SSA, expanded access saw
new users jump from 4154 in 2016
to more than 517,000 in 2020,
or 56 per cent of the global total.
Out of the 10 countries with
the highest number of PrEP users,
seven are in SSA. South Africa
surpassed 100,000 users as of
December 2020, while Kenya has
about 83,000, followed closely
by Zambia and Uganda.
Segal attributed the trend
to investments from the USPresident’s Emergency Plan For
AIDS Relief, a major funder of
HIV programmes across SSA,
along with commitments by
many governments in the region
to offer wide access to PrEP.
“In South Africa and Kenya,
credit policies [to fund access],
and guidelines were adopted,
ambitious targets were set and
sufficient resources were allocated
by national governments to meetthem,” Segal told New Scientist.
She says that SSA countries have
ensured the drugs are available to
the general population, as well as
groups at greater risk of infection,
such as men who have sex with
men and sex workers. This
contrasts with the approach in
countries such as the UK, which
has long resisted providing
general access to PrEP.
Segal says access can be further
expanded in SSA, such as by
making PrEP available at local
pharmacies and informing the
public about the drug. “Many ofthe general population still don’t
know that PrEP exists or what it
is or how to access it. So we really
need to normalise it and increase
demand,” she says.
John Nkengasong at the Africa
Centres for Disease Control and
Prevention says the coronavirus
pandemic may hamper these
efforts. “Covid-19 has impacted
all our health programmes, not
just HIV,” he says.
But in Nigeria, where PrEP users
grew from 76 in 2016 to nearly
32,000 in 2020, there is optimism
that the decision to centrally
coordinate HIV programmes will
further expand access to PrEP.
Ifeanyi Nsofor, CEO of Nigerian
public health consultancy
EpiAfric, says that with HIV
prevalence significantly falling in
Africa, efforts are now turning to
prevention measures such as PrEP,
especially among young people.
“Focus should be on prevention
and scaling up youth-friendly
health facilities and deploying
technology to provide information
on PrEP and other issues to
adolescents via mobile phones
and social media,” he says. ❚Paul AdepojuDANIEL^ BORN/THE
TIMES
/GALLOIMAGES
/GETTY^ IMAGESTechnologyAI can predict the
emotions a painting
will evoke in usMONET’S paintings of gardens can
make a viewer feel content, while
Dali’s surreal melting clocks elicit
fear or confusion. Now, an AI art
critic can predict the emotions that
famous paintings will evoke and
can sometimes explain them as
convincingly as a human.
AI image analysis often focuses
on describing what is going on in
pictures, but the subjective feelings
that works of art arouse have just asbig an effect on human behaviour,
says Panos Achlioptas at Stanford
University in California.
Being able to predict and
emulate these responses could
help machines interact with us
more seamlessly, says Achlioptas,
so his team built a large data set
of human reactions to art using
online surveys.
They asked more than 6000
participants to choose the dominant
emotion elicited by 81,
paintings in the ArtEmis data set
and write a caption describing
what it was about the artwork that
guided their decision. Each paintingwas analysed by at least five people.
The images, emotion labels and
captions were used to train an AI,
which was then challenged to
predict what emotion paintings it
hadn’t seen before would evoke
and provide short explanations.
Judging its output is inherently
difficult, says Achlioptas, because
there is no right answer. A majority
of annotators agreed on the
dominant emotion in just 45 percent of the ArtEmis paintings.
So the researchers carried out
a form of Turing Test by showing
people a painting alongside a
caption from the AI and one from
an annotator, and asking them
to guess which was written by a
person. The AI’s captions passed
as human 50 per cent of the time
(arxiv.org/abs/2101.07396).
Achlioptas admits that the AI’s
captions aren’t as diverse or creative
as human ones, but says the early
results are promising and the data
has been made open source so
others can improve on the models. ❚
Edd GentMedicineAfrica leads HIV prevention effort
Half the people taking PrEP to reduce risk of HIV infection are in African nations
“Judging the AI’s output is
inherently difficult because
there is no right emotional
response to an artwork”Pre-exposure prophylaxis
can drastically cut the risk
of HIV infections