SPURRED BY COVID, PUBLIC HEALTH GETS PRECISE
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Feature
TODD HEISLER/THE NEW YORK TIMES/ REDUX/EYEVINE
F
A man has a nasal swab at a mobile COVID-19 testing site in Manhattan, New York City.
SPURRED BY COVID,
rom their offices in a high-rise build-
ing in Queens, epidemiologist Sharon
Greene and her colleagues watched
the COVID-19 pandemic sweep
PUBLIC HEALTH
through New York City in April 2020.
Using an open-source data-analytics
program called SaTScan, her team
mapped outbreaks as they unfolded
across individual neighbourhoods, almost in
GETS PRECISE
real time. This sophisticated approach relied
on detailed data from hospitals and laborato-
ries, and showed that the virus wasn’t affecting
all New Yorkers equally. That knowledge helped
Greene’s team at the New York City Department
of Health and Mental Hygiene to distribute
testing resources and protective gear such as
Inspired by precision medicine, some public-health masks and gloves to the right places.
researchers are trying to solve problems using big data and It was a different approach from New York
City’s typical pandemic response plan, which
technology. Others fear that these tactics could fail millions. advised largely blanket policies such as lock-
By Carrie Arnold downs and mass testing.
“Instead of just parking a testing van some-
where in an affected zip code, we can park it
at an intersection in the middle of the cluster,”
Greene says. “It’s hyper-local public health.” By
the middle of the year, cases in the city began
to drop.
18 | Nature | Vol 601 | 6 January 2022
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The tech-centric, targeted approach used by
Greene and other epidemiologists to address
COVID-19 is part of a burgeoning field known
as precision public health. The concept is a
modernization of the 150-year-old field of
epidemiology, similar to how precision med-
icine has transformed health care, says Muin
Khoury, director of the Office of Genomics and
Precision Public Health at the US Centers for Dis-
ease Control and Prevention (CDC) in Atlanta,
Georgia, and one of the idea’s biggest advocates.
The definition of precision public health is
sprawling and variable: for most researchers
in the field it includes a sweep of data-driven
techniques, such as sequencing pathogens
TED S WARREN/AP/SHUTTERSTOCK
to detect outbreaks and turbo-charging data
collection to monitor harmful environmental
exposures. It also encompasses an ambition to
target interventions to specific people who
need them.
For Caitlin Allen, an epidemiologist at
the Medical University of South Carolina in
Charleston, who organized a meeting on pre- Data-heavy approaches have helped researchers to track the COVID-19 pandemic.
cision public health in October last year, the
kernel of the idea is simple. “You’re doing all Soho, in central London. Physician John Snow of Salmonella, Listeria and Escherichia coli
the things you normally do in public health, worked just a few streets away. Snow went from were investigated and halted when they might
but the unique aspect is that we’re using big door to door and began to plot cholera cases otherwise have gone unnoticed.
data and predictive analytics to be more tar- on a map. He found that people who got their Khoury saw similar potential in other genetic
geted and tailored in these efforts,” she says. water from a pump on Broad Street were much technologies. As a paediatrician and geneticist,
The concept promises to save money and lives more likely to develop cholera. he had spent years studying a genetic condition
by targeting interventions to the right people. Snow’s statistics might seem pedestrian called familial hypercholesterolaemia (FH),
To Sandro Galea, an epidemiologist and dean to modern epidemiologists, but they were which causes extremely high cholesterol levels
of the Boston University School of Public Health, state-of-the-art in 1854. If Snow had had and can lead to heart attack and stroke. Despite
Massachusetts, and others, however, it sounds access to SaTScan, he would have used that, being readily recognized with basic screening
too good to be true. “We’re all looking for the Quackenbush says, and maybe brought the tests and a proven therapy (high-dose statins)
silver bullet, but there isn’t one,” says Galea. outbreak to a halt much more quickly. that reduces the risk of heart disease by 80%,
The debate over the merits of precision “We just have access to unprecedented many of those with FH go undiagnosed.
public health has typically taken place in the quantities of data,” Quackenbush says. With less than 1% of the population affected,
pages of academic journals. But funders are More than a century ago, the first municipal public-health investments to screen everyone
putting hundreds of millions of dollars behind public-health departments in cities such as would be impractical and wasteful.
precision-public-health initiatives, and some London and New York aimed to improve the To Khoury and others, FH seemed like the
researchers worry about the implications for health of large swathes of the population by perfect place for precision public health to
conventional public health. Spending on public building sewage systems, removing rubbish, shine. A US team is piloting a machine-learning
health is already sliding: although national purifying drinking water and collecting basic method that scans health records (including
health expenditure in the United States grew information on births and deaths. The efforts standard blood cholesterol measurements)
by 4.3% from 2008 to 2018, researchers found were broad both because all residents would and identifies those likely to have FH3. This
no change in public-health spending1. benefit from these interventions, and because strategy could help to ensure that individuals
Galea is concerned that the precision early sanitation workers had little information with FH get appropriate screening and treat-
approach is diverting attention away from on where to target their resources. ment without wasting resources on the 99%
regular public health. “I worry that this is As time passed, epidemiology grew more of people without FH.
becoming the great sucking sound where sophisticated and precise as researchers were Soon after Khoury’s initial blog post, the term
we focus all our energy on technological able to home in on specific clusters of disease start popping up everywhere. In June 2016, the
approaches and we don’t focus on more foun- and ever more detailed risk factors for future University of California, San Francisco, hosted
dational issues that will make a difference in illnesses2. the first precision-public-health conference.
the lives of millions,” Galea says. In that sense, the concept of precision In the same year, the Zika virus swept across
public health is not new — but the phrase is the Western Hemisphere. Health officials in
Think local recent. Khoury coined it in a March 2015 blog Miami, Florida, began preparing for it to reach
For John Quackenbush, a biostatistician at the post as he watched the genomics revolution the United States. Using a detailed geographic
Harvard School of Public Health in Boston, the take hold in medicine. He wanted to see that information system to map locally acquired
push for precision public health has existed same energy spill over into public health. cases, they were able to target mosquitoes with
since the birth of epidemiology. To some extent, it already had. In 1996, the insecticides sprayed across just two blocks of
In the 1850s, citizens of London stared CDC launched PulseNet, which used DNA Miami, rather than dousing whole neighbour-
down a different outbreak: cholera. The dis- fingerprinting of bacteria that caused food hoods or even the entire city.
ease killed millions of people in the nineteenth poisoning to detect large, diffuse outbreaks Precision approaches are taking off in
century. In 1854, a string of cases appeared in across county and state lines. Large outbreaks many more guises. The Bill & Melinda Gates
Corrected 11 January 2022 | Nature | Vol 601 | 6 January 2022 | 19
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Foundation has given a total of $271 million more challenging strategies that researchers Galea agrees. But he also points out that the
to the Child Health and Mortality Prevention know would improve people’s health, such first wave of the pandemic overwhelmed New
Surveillance network led by Emory University as universal health care, welfare support and York City before it could scramble adequate
to map out areas of greatest maternal-health reducing income inequalities, according to resources to mount a defence. Galea says
problems and childhood malnutrition across Mira Vegter, a social scientist at Wageningen that investments in basic public health, such
Africa and Asia. The goal is to help govern- University in the Netherlands. as improving housing and requiring paid sick
ments, charities and other advocates to create “We can be blinded by the data opportu- leave for workers, would have benefits during
evidence-based policies to target childhood nities at the expense of some of the more a pandemic — and ripple effects beyond.
disease where it is most severe. dynamic social questions,” she says. Besides, says Thomson, pathogen sequenc-
And in September 2019, the Rockefeller But in an emergency, there might not be ing and other techniques rely on the ability
Foundation launched a $100-million Precision time to rise to the challenge of addressing of public-health systems to step in and do
Public Health Initiative dedicated to using pre- complex social questions. As the COVID-19 something to stem the outbreak. “It’s great
dictive analytics to prevent health threats, and pandemic hit, some data-heavy techniques and it’s important but it has its limitations,
exploiting big data to address the social factors got the chance to prove their worth. especially when public-health departments
that lead to poor health, such as discrimination are overwhelmed,” she says.
and poverty. During the pandemic, the foun- Hi-tech health It’s easy to forget that access to basic health
dation created an interactive dashboard, Even before the pandemic, many public-health data, such as birth and death certificates and
containing detailed statistics on various departments, including New York City’s, had communicable-disease reporting, is the fuel
COVID-19 testing strategies, to help educators been honing real-time data analytics to trace that drives the public-health machine, says
determine the safest way to reopen schools. infectious-disease outbreaks4,5. Angeline Ferdinand, a public-health researcher
The idea seemed so promising that advo- As the coronavirus spread through New at the University of Melbourne, Australia.
cates began to wonder whether precision York, Greene’s goal was to focus on areas where Even basic data are lacking in some places, she
public health had any downsides. Its critics transmission was growing faster than the points out — let alone the ability to perform
would find plenty. citywide average. Over time, the work allowed whole-genome sequencing and the informa-
her to begin making short-term predictions ticians to put it to use. This could exacerbate
Woolly definition (called nowcasts) about future cases6. inequalities both within and between countries.
When you ask Galea what his problems are with “It’s hard to shift resources around in real
precision public health, he laughs as if to say, time,” Greene says. “If you can alert people Targeted treatment
“Where to start?” earlier, they have more of a chance to protect For Allen and Khoury, however, there are many
His biggest complaint is that no one has themselves, and the more likely you are to more ways in which new technologies and
defined exactly what precision public health is. prevent another infection.” genomic information could pinpoint those
One common description is ‘the right interven- As well as tracking cases of COVID-19, most in need of help.
tion to the right population at the right time’. epidemiologists around the world also began Take cancer, for example. Allen is piloting
But critics say this isn’t any different from to track how the SARS-CoV-2 virus itself was a project that analyses existing scans with
what John Snow did more than 150 years ago. spreading and changing, to help inform what machine learning to help identify individu-
Dubbing it ‘precision’ is at best extraneous and measures were likely to be most effective. Over als at high genetic risk of developing cancer,
at worst deceptive, Galea says. “This is what even if they don’t have a family history of the
public health does anyway.” “I think there’s a way to disease. These people could benefit from
What makes precision public health prob- more-intensive cancer screenings such as
lematic, he says, is that it focuses on new
marry this whizz-bang mammograms and colonoscopies. She recently
technologies instead of the bread-and-butter stuff with old-school completed a study that showed information
methods that have made the field so successful. public health.” collected by chatbots on medical websites
With decades of public-health funding cuts, could accurately predict whether a person met
Galea and his colleague Merlin Chowkwanyun criteria for genetic testing for several cancers7.
at the Columbia University Mailman School the past 15 years, public-health laboratories Whether or not researchers see a conflict
of Public Health in New York City say they around the world have been sequencing the between public health’s fundamental mission
understand why epidemiologists and other genomes of infectious pathogens — which and its new ‘precision’ arm, both sides agree
professionals need to use snappy terms to change slightly as they are passed between on one thing: public health will continue to be
secure even basic funding. However, they people — as a way to connect the dots on who of utmost importance in the coming decades.
worry that the seemingly subtle change to was infecting whom. “The goal is to improve the health of the
‘precision’ approaches conceals a broader It’s also how scientists noticed variants of whole population, using all the tools that we
shift away from public health’s historical SARS-CoV-2 emerging and spreading. Several have, whether we call them precision public
ideals of improving the well-being of even large databases of its genome sequences health or not,” Khoury says.
the most marginalized populations. allow virologists to watch in near real time as
The core of public health, says David coronavirus variants popped up and began Carrie Arnold is a science journalist based
Taylor-Robinson, a health-equities scientist at to circulate. “It’s like opening a window into near Richmond, Virginia.
the University of Liverpool, UK, is to improve a whole new world,” says Emma Thomson, a
1. Alfonso, Y. N., Leider, J. P., Resnick, B., McCullough, J. M. &
the health of populations. The ‘precision’ in virologist at the University of Glasgow, UK. Bishai, D. Health Aff. 40, 664–671 (2021).
precision public health, notes Taylor-Robinson, “You see so much more detail,” she says. 2. Institute of Medicine. in The Future of Public Health Ch.3
refers to individuals, not populations. Improv- Pathogen sequencing in public health has (National Academies Press, 1988).
3. Myers, K. D. et al. Lancet Digit. Health 1, E393–E402 (2019).
ing the health of individuals is clinical medicine, been a clear success, even to those wary of pre- 4. Latash, J. et al. Morb. Mortal. Wkly Rep. 69, 815–819 (2020).
not public health. In that sense, he says, cision methods. “To not use these technologies 5. Greene, S. K., Peterson, E. R., Kapell, D., Fine, A. D. &
“precision public health is an oxymoron”. strikes me as unambitious,” says Chowkwanyun. Kulldorff, M. Emerg. Infect. Dis. 22, 1808–1812 (2016).
6. Greene, S. K. et al. JMIR Public Health Surveill. 7, e25538
The danger of this contradiction is that it “I think there’s a way to marry this whizz-bang (2021).
becomes easier to lose sight of the lower-tech, stuff with old-school public health.” 7. Ritchie, J. B. et al. Hered. Cancer Clin. Pract. 19, 31 (2021).
20 | Nature | Vol 601 | 6 January 2022
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.Correction
This Feature gave an out-of-date affiliation
for Caitlin Allen. She is now an epidemi-
ologist at the Medical University of South
Carolina in Charleston.
Corrected 11 January 2022
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