14 SUNDAY, AUGUST 9, 2020BY NOW,most readers have surely heard of
the science of disease modeling or the “R-
naught,” the mathematical concept that ex-
presses the number of new infections that a
typical infectious person generates.
If the R-naught, or the basic reproduc-
tive number, is above one, then every per-
son with Covid-19 will, on average, infect
one or more people, and the prospect of be-
ing released from our pandemic purgatory
diminishes. By contrast, if that number is
below one, then, like a skier who has
reached the top of a cable lift and whose
only way out is down, we can soon look for-
ward to resuming our pre-Covid lives.
Since SARS-CoV-2 emerged in or near an
animal market in Wuhan, China, in the clos-
ing months of 2019, we’ve been mesmer-
ized by this number and the modelers, such
as Neil Ferguson at Imperial College, Lon-
don, whose ability to plot the shifts of the
R-naught have made them the secular
sages of the pandemic.
Among their number is Adam
Kucharski, an associate professor at the
London School of Hygiene & Tropical Medi-
cine who sits on a key scientific committee
advising the British government on its re-
sponse to the pandemic. For Kucharski the
R-naught holds the key to what he calls the
“rules of contagion” — rules that he asserts
apply not only to biological infections but to
social contagions and stuff that spreads on-
line (think financial panics, gun crime and
ice-bucket challenges).
But do they? Is contamination with a liv-
ing virus — which presupposes the messy
materiality of actual bodies — the same as
a “virtual infection” with a piece of aber-
rant malware, or a catchy idea propagated
via social media?
Up to a point. In this smart and engaging
tour of epidemiology, written before the
pandemic, Kucharski makes a convincing
case that just as the arc of an epidemic de-
pends on the transmissibility of a virus and
a population’s susceptibility to infection, so
online contagions obey similar rules. It all
goes back to his hero, the early-20th-cen-
tury British malariologist Ronald Ross, and
his theory of “independent” and “depend-
ent happenings.” The first type includes
noninfectious diseases, such as brain can-
cer, accidents or divorce. If it happens to
you, it generally doesn’t affect anyone else.
However, with dependent happenings,
what happens to one person is a result of
what has happened to others. In the sim-
plest type of outbreak, affected people pass
along the condition and, once affected, re-
main so. In this situation the happening will
gradually permeate through the popula-
tion and eventually plateau. Such epi-
demics follow the shape of a letter S, grow-
ing exponentially at first and then leveling
off. By contrast, many infectious disease
epidemics tend to look like inverted V’s be-cause once people have been infected and
have recovered, they are immune to fur-
ther infection and the pool of susceptible
people shrinks.
But whereas with contagious disease if
you have good data you can estimate just
how many people have been infected and
how many are still susceptible — and hence
the R-naught — this is not the case with fi-
nancial contagions, where those affected
can always borrow more money to lever-
age further trades. Nor is it true of conspir-
acy theories and other idiotic ideas that cir-
culate online, for which there appears to be
no end to people’s gullibility or susceptibil-
ity. (Worst of all, Kucharski says, is the gull-
ible celebrity, who is both susceptible and
hugely influential.)
The good news is that some social media
platforms are finally recognizing they have
a duty to inoculate users against such igno-
rance by slapping prominent warnings on
erroneous and incendiary posts — or in the
extreme cases, removing them. When it
comes to Covid conspiracy theories, such
as the daft idea that the virus is spread by
5G cell towers, users can also be directed to
independent fact-checking sites, such as
Full Fact.
“Along the way,” Kucharski writes,
“we’re finding new ways to speed up bene-
ficial ideas and slow down harmful ones.”
Unfortunately, as with the search for a vac-
cine against Covid, that is easier said than
done. 0It’s Catching
A scientist explores contagion, in bodies and in minds.
By MARK HONIGSBAUM
THE RULES OF CONTAGION
Why Things Spread — and Why They Stop
By Adam Kucharski
341 pp. Basic Books. $30.
MARK HONIGSBAUMis a medical historian and
the author of “The Pandemic Century: One
Hundred Years of Panic, Hysteria, and Hu-
bris.”
RICHARD A. CHANCEHEAVILY PREGNANT WITHa second child,
Heather Lanier deliberately read a book
by a mother whose infant son was dying.
She’s not a masochist, only a realist.
“I needed this story,” Lanier writes. “I
needed to get as close as possible to the ab-
solute worst that I feared.”
Lanier’s memoir is now on the short list
of books I’ll give, when the time comes, to
my own pregnant daughters. It’s not just
because a wise woman ought, in this as in
all else, to be prepared for disaster even as
she hopes for delight. It’s not even because
Lanier’s writing is clean and beautiful.
In this story of her rare girl, Lanier
shines a clear light on what we sign up forwhen we allow a human soul to come
through us and into the world, in whatever
“interesting and beautiful package” that
soul might find.
“I tried to make a superbaby,” Lanier
confesses. Within 20 pages we’ve wit-
nessed the birth of a too-tiny girl
and eavesdropped on the first
of a series of grim conversa-
tions with doctors, some of
them astonishingly insen-
sitive: “Your child will be
significantly disabled. If
she lives at all.”
One doctor notes Fiona’s
diminutive size, her wide-set
eyes and Y-shaped butt crease,
and concludes that something is
wrong. “It’s either bad seed,” he
says, “or bad soil.”
Wolf-Hirschhorn syndrome, the genetic
disorder that afflicts Lanier’s daughter, is
characterized by the deletion of genetic
material, leading to a constellation of se-
vere physical and mental disabilities.
Pregnant women who have adhered to
superbaby regimens announce their new-
borns’ perfect Apgar scores on Facebook.
New mothers told of minor imperfections
blame themselves. Bad seed, bad soil.
So sure are we that the sine qua non of a
life worthy of love lies in meeting certain
standards of “normality” that the prenatal
detection of much milder disabilities or
reparable defects will prompt a conversa-
tion. About choices.
“Abort it and try again,” the evolution-
ary biologist Richard Dawkins wrote to a
mother pregnant with a Down syndrome
child.
“Among my fellow Wolf-Hirschhornsyndrome parents, I’ve heard horror
stories,” Lanier writes. “One woman re-
ceived her daughter’s diagnosis in utero
and was told by her OB that she ‘should’
terminate. At 26 weeks pregnant, she was
given three out-of-state locations to call
immediately. (She never did.) Another
mother, also pregnant, met with a genet-
icist who repeatedly used the word ‘bur-
den,’ explaining that her daughter would
not only be a burden to the family but to
society.”
“I didn’t sign up for this,” Lanier cries to
her sister, and then corrects herself: Of
course she did. The parent signs up for
whatever the child brings.
Fiona was born before her disability
could be discovered. Her parents received
hints from presumably well-meaning phy-
sicians that there remained options by
which they might liberate themselves
from the burden of their daughter. “Here’s
something a parent of a typical child prob-
ably never has to suffer through,” Lanier
writes crisply. “A conversation with a doc-
tor in which the doctor wonders aloud
whether a child like theirs can be ethically
killed.”
It is love that makes such choices un-
thinkable. Fiona is not a diagnosis but a
person, and a beguiling one. OK, so she
doesn’t hit the developmental mile-
stones that other babies do —
those enormous babies, freak-
ish in their roly-poly athleti-
cism, that Lanier observes
with wonder and envy at
church or the pediatrician’s
office. Her girl lies there,
tiny and still, gazing about
with onyx eyes. She doesn’t
roll over or sit up, babble or
crawl. But she does grow. She
giggles. (“They were faint, like
bubbles from the tiniest fish.”) A
speech therapist observes that
she can combine two elements — grunt
plus gesture — to convey meaning. This
means Fiona has language.LANIER TEASES OUTthe glory, charm and
humor of these moments, letting us adore
her child with her. And then she delivers a
hard jab to the sternum: “I was learning:
The simple act of loving her was counter-
cultural.”
Refreshingly, Lanier’s husband, Justin,
an Episcopal priest, is given room to
demonstrate the ways in which practic-
ing a religion prepares one usefully for a
crisis. His training in Christian contem-
plative prayer and Zen meditation gives
him strength that Lanier both leans on
and is grateful for. As mother and writer,
she draws on a liberal, questioning but
questing faith, and brings to both voca-
tions the humane message of Christ on
his cross and Siddhartha’s 49 days be-
neath the Bodhi tree: You, my beloved
child, are worth this much... and
more. 0Baby of Mine
A mother recounts a family’s love for their ‘rare girl.’
By KATE BRAESTRUPRAISING A RARE GIRL
A Memoir
By Heather Lanier
320 pp. Penguin Press. $27.KATE BRAESTRUPis the author of “Here if You
Need Me,” “Anchor and Flares” and “Begin-
ner’s Grace.”Heather LanierPHOTOGRAPH BY JUSTIN LANIER