The New York Times - USA (2020-10-17)

THE NEW YORK TIMES, SATURDAY, OCTOBER 17, 2020 Y A

In a flurry of memos released
this week and last, the White
House physician, Dr. Sean Conley,
stated that President Trump no
longer posed a transmission risk
to others — an assessment, he
noted, that was largely precipi-
tated by the results of a bevy of
“advanced diagnostics.” The dec-
larations have helped clear Mr.
Trump to return to the campaign
trail, including a town-hall-style
event hosted by NBC News on
Thursday evening.
Outside experts have also said
that Mr. Trump, who reportedly
began feeling sick about two
weeks ago, is probably no longer
infectious. But most have based
such assessments on the trajec-
tory of the president’s symptoms
— not the results of his tests.
There exists no test that can
definitively determine whether
someone who caught the corona-
virus is still contagious. “We do
not have a test for cure, and we do
not have a test for infectiousness,”
said Omai Garner, a clinical micro-
biologist at the University of Cali-
fornia, Los Angeles.
Experts have criticized the ad-
ministration’s overreliance on
tests to keep the coronavirus out
of Mr. Trump’s inner circle. Now,
they said, the White House ap-
pears to be leaning too heavily on
tests to break the president out of
isolation.
Not all coronavirus tests are de-
signed to detect the same parts of
the virus. And a negative on one
test does not necessarily guaran-
tee a negative on another.
“We don’t just look at these
tests in the context of ‘Coronavi-
rus, yes or no,’ ” said Karissa Cul-
breath, a clinical microbiologist at
TriCore Reference Laboratories
in New Mexico. “Each test looks
for a different aspect of the virus.”
As recently as Tuesday, for in-
stance, a rapid test called the Bi-
naxNOW was unable to detect the

coronavirus in Mr. Trump. But re-

sults yielded from a laboratory

test, which used a slower but more

accurate technique called poly-

merase chain reaction, or P.C.R.,

showed he still carried genetic

material from the virus at low lev-

els in his body.

The White House also reported

using two experimental ap-

proaches on Mr. Trump: a viral

culture, in which researchers in a

laboratory tried to grow the co-

ronavirus from a sample taken

from the president, and a test for

subgenomic RNA, a proxy for the

presence of actively replicating vi-

rus.

Many types of P.C.R. and anti-

gen tests for the coronavirus have

received a green light from the

Food and Drug Administration.

But viral culture and probes for

subgenomic RNA are not cur-

rently part of the standard testing

tool kit, Dr. Culbreath said.

P.C.R.-based tests are some of

many among a suite of so-called

molecular tests, which hunt for

genetic material exclusive to the

coronavirus. These tests include

an amplification step, wherein the

genetic material is copied over

and over until it reaches detect-

able levels, revealing even very

small amounts of the virus.

Some P.C.R.-based tests can

also give an indication of how

much virus is lingering in the

body — a number called the cycle

threshold, or C.T., which increases

as the virus becomes scarcer.

A recent P.C.R. test taken by Mr.

Trump yielded a C.T. of 34.3, after

steadily increasing for several

days. Researchers have had trou-

ble growing the virus out of sam-

ples taken from people whose

P.C.R. tests crest above the low

30s. But exceptions to this trend

do exist, and cycle-threshold read-

ings are often inconsistent among

different types of P.C.R.-based

tests, and even among laborato-

ries using the same test.

“We cannot say, ‘A C.T. value of

34 does not make someone infec-

tious’ across the board,” Dr. Cul-

breath said. “It’s not a universal

answer.”

Tests like the BinaxNOW, on the

other hand, are antigen tests,

which search for bits of proteins,

or antigens, made by the corona-

virus. Unlike P.C.R.-based tests,

antigen tests do not include a step

in which they amplify their tar-

gets, making them faster and

more convenient but less reliable

at finding the virus when it is in

low abundance. Some P.C.R.-

based tests are thought to be

many thousands times more sen-

sitive than antigen tests.

It’s thus very possible to be anti-

gen negative but P.C.R. positive,

while still harboring the virus in

the body, Dr. Culbreath said.

The BinaxNOW has emergency

clearance from the F.D.A., but only

when administered within seven

days after the onset of symptoms.

Researchers do not yet know how

the test will perform in people out-

side this window. Mr. Trump re-

ceived several of these tests dur-

ing his second week of illness, all

of which returned negative re-

sults.

“The tests have to be used when

they’re supposed to be used,” said

Andrea Prinzi, a clinical micro-

biologist at the University of Col-

orado, Anschutz. “That’s when

they’re going to help you the

most.”

Both P.C.R. and antigen tests

have another limitation: They

look for hunks of the virus’s anat-

omy — debris from the pathogen

— and cannot determine whether

the virus is still active. Some peo-

ple who have been infected by the

coronavirus may register as

P.C.R. positive for weeks, even

months, after they are no longer

contagious or ill, simply because

tests are picking up on harmless

souvenirs of an infection long

past.

“Neither is a measure of actual,

live virus,” Dr. Garner said, of

P.C.R. and antigen tests.

That’s where viral culture

comes in. Scientists can take a

sample from a person’s airway

and then try to coax the coronavi-

rus into infecting cells in a lab. But

these procedures are not widely

available to the public, because

they have to be performed in a

high-containment facility by peo-

ple specifically trained to work

with deadly pathogens.

These restrictions have led sev-

eral scientists to experiment with

P.C.R.-based tests that search spe-

cifically for subgenomic RNA as a

possible proxy for active virus.

Subgenomic RNA is a type of ge-

netic material that is produced

only after the coronavirus has in-

fected a human cell. The com-

pound can thus act as a sort of mo-

lecular beacon that can alert re-

searchers to a virus that has

started to reproduce itself, with-

out the need to grow the danger-

ous pathogen.

Dr. Conley’s memos about Mr.

Trump appear to indicate that the

president is no longer producing

samples with detectable subge-

nomic RNA. Researchers have

also tried to culture the coronavi-

rus outside of his body, although

few details on this have been

shared. Virus that can be cultured

is not necessarily transmittable,

or vice versa.

Neither viral culture nor subge-

nomic RNA tests are approved for

widespread use, Dr. Garner noted.

Researchers doing these studies

might not perform their experi-

ments in the same way, making

any results difficult to interpret

without more information how,

and by whom, they were obtained.

Guidelines published by the

Centers for Disease Control and

Prevention stipulate that symp-

toms — not test results — should

be the primary motivator for end-

ing a person’s isolation. People

with mild or moderate Covid-

should isolate for least 10 days af-

ter their symptoms start. That

timeline could extend up to 20

days if their symptoms are severe.

Before advising someone to end

their isolation for Covid-19, “I

would want to know about their

symptoms,” said Dr. Krutika Kup-

palli, an infectious disease physi-

cian in South Carolina. While in-

formation on tests wouldn’t hurt,

that data should be considered

secondary to how the patient is

feeling. Otherwise, the tests might

be not just unhelpful, but also a

“waste of resources,” Dr. Kuppalli

said.

“If the president meets C.D.C.

guidelines, he can come out of iso-

lation,” said Dr. Alexander McAd-

am, director of the infectious dis-

eases diagnostic laboratory at

Boston Children’s Hospital. “But I

don’t see testing as a get-out-of-

jail-free card.”

MEDICAL RESEARCH

Negative Tests Are Not a Full Picture,

Experts Say, Pointing to Limitations

By KATHERINE J. WU

On Tuesday, a laboratory test found that President Trump carried low levels of the virus, but a rap-

id test came back negative. Researchers say that different techniques can have different results.

DOUG MILLS/THE NEW YORK TIMES

There’s no way to

know if a person is

still infectious.

Tracking an OutbreakThe Politics and the Science

WASHINGTON — In late Sep-
tember, a Nobel Prize-winning
economist emailed Dr. Scott W. At-
las, a White House coronavirus
adviser, in what he saw as a last-
ditch effort to persuade the Trump
administration to embrace a
sharp increase in testing and iso-
lating infected patients. The plan,
meant to appeal to a president
who has complained that positive
tests make his administration
look bad, would not “generate any
new confirmed cases.”
Dr. Atlas, a radiologist, told the
economist, Paul Romer of New
York University, that there was no
need to do the sort of testing he
was proposing.
“That’s not appropriate health
care policy,” Dr. Atlas wrote.
Dr. Atlas went on to mention a
theory that the virus can be ar-
rested once a small percentage of
the United States population con-
tracts it. He said there was a “like-
lihood that only 25 or 20 percent of
people need the infection,” an ap-
parent reference to a threshold for
so-called herd immunity that epi-
demiologists have widely dis-
puted.
The call for more widespread
testing and isolation, Dr. Atlas
wrote, “is grossly misguided.”
The exchange highlights the re-
sistance in the White House to-
ward adopting a significantly ex-
panded federal testing program,
including efforts to support in-
fected patients in isolation and
track the people they have been in
contact with, even as cases and
deaths continue to rise nation-
wide. That resistance has become
a sticking point in negotiations
over a new economic stimulus
package, with the administration
and top Democrats yet to agree on
the scope and setup of an ex-
panded testing plan.
Many public health experts,
and some economists like Mr.
Romer, say that a far more sweep-
ing program would save lives and
bolster the economy by helping as
many Americans as possible learn
quickly if they are infected — and
then take steps to avoid spreading
the virus.
Dr. Atlas and other administra-
tion officials playing influential
roles in the government’s virus re-
sponse effectively say the oppo-
site: that more widespread test-
ing would infringe on Americans’
privacy and hurt the economy, by
keeping potentially infected work-
ers who show no symptoms from

reporting to their jobs.

Congressional Democrats have

grown so frustrated with the ad-

ministration’s testing efforts that

as part of any agreement on a new

aid package, they insisted on lan-

guage that would force the gov-

ernment to carry out a far more

prescriptive national program for

administering and distributing

tests.

While White House negotiators

resisted those demands for

months, Treasury Secretary

Steven Mnuchin has said he will

accept such wording with minor

edits. Top Democratic staff, in-

cluding the top health adviser to

Speaker Nancy Pelosi of Califor-

nia, walked Mr. Mnuchin through

the party’s proposal on Friday, ac-

cording to a person familiar with

the discussion, but they had yet to

announce agreement on language

by early evening.

In an interview on Thursday,

Dr. Atlas, who is not involved in

the stimulus talks, said that the

United States had a “massive”

testing program over all, but that

it should be used strategically to

protect vulnerable populations,

like nursing home residents — not

young, healthy individuals who he

said were at low risk of contract-

ing the disease. He said that large-

scale government test and isolate

programs infringed on civil liber-

ties, and that new research had

persuaded him that herd immuni-

ty might be achieved once 20 or 40

percent of Americans are in-

fected.

“The overwhelming majority of

people who get this infection are

not at high risk,” Dr. Atlas said in

the interview. “And when you

start seeking out and testing

asymptomatic people, you are de-

stroying the workforce.”

Many congressional Republi-

cans, who prefer to leave testing

decisions to states, share Dr. At-

las’s concerns about federal test-

ing programs, a complication if

Mr. Mnuchin and Ms. Pelosi do

agree on a nearly $2 trillion eco-

nomic stimulus deal.

Mr. Mnuchin said on Thursday

that the pair had settled on spend-

ing an additional $75 billion for

testing and tracing. But the sides

have not yet reached agreement

on the language that Democrats

have demanded for a national

testing strategy, including time-

lines and benchmarks for allocat-

ing testing supplies and testing

communities heavily affected by

the virus. Democrats have been

wary that the administration

would actually spend the money

as intended without specific legis-

lative parameters.

Ms. Pelosi said she had not re-

ceived proposed changes from Mr.

Mnuchin as of early Friday

evening, saying in an interview on

MSNBC, “we’re making progress

— we have to have clarification in

language.” The pair are scheduled

to speak Saturday evening.

“The devil and the angels are in

the detail,” she said, adding that

she was opposed to “giving the

president a slush fund” instead of

“a prescription for what we need,

what scientists tell us to need to

stop the spread of this virus.”

Experts from a wide range of

fields have repeatedly denounced

the lack of testing in the United

States. Despite Mr. Trump’s re-

peated affirmations that the coun-

try has done more testing than

any other nation, researchers

have noted that 991,000 or so tests

done each day were still not

enough to keep in check a virus

that has infected more than eight

million people nationwide. Tests

can individually diagnose people

who might unknowingly carrying

the virus. At the population level,

they can also help health officials

monitor any spread and pinpoint

and quash outbreaks before they

spin out of control.

Others have cautioned against

an overreliance on testing as a

preventive measure, noting that,

in the absence of standards like

physical distancing and mask

wearing, testing alone cannot

fully contain a virus that spreads

wherever people tend to gather,

regardless of whether those in-

fected are exhibiting symptoms.

“No testing scheme, no test is

perfect. There will always be peo-

ple who go undetected,” said Dr.

David Dowdy, an infectious dis-

ease epidemiologist at Johns Hop-

kins University who has re-

searched and written about herd

immunity. “The best way to pro-

tect the most vulnerable is to re-

duce the amount of virus that’s in

the population that can get

through all of those testing

schemes and cause destruction.”

Dr. Atlas’s position has been

challenged by medical advisers

around him who have back-

grounds in infectious disease re-

sponse, revealing a significant rift

in the White House over the right

approach. Dr. Deborah L. Birx, the

White House’s coronavirus re-

sponse coordinator, has pushed

for aggressive, broad testing even

among young and healthy people,

often clashing with Dr. Atlas in

meetings.

“I would always be happy if we

had 100 percent of students tested

weekly,” Dr. Birx said on Wednes-

day in an appearance at Penn

State University, “because I think

testing changes behavior.”

Dr. Atlas at one point influenced

the administration’s efforts to in-

stall new Centers for Disease Con-

trol and Prevention guidance that

said it was not necessary to test

people without symptoms of

Covid-19 even if they had been ex-

posed to the virus, upsetting Dr.

Birx and Dr. Robert R. Redfield,

the C.D.C. director.

The administration’s efforts to

fund federal and state testing

have long been fraught. In July, as

administration officials and top

Senate Republicans clashed over

the contours of their initial $1 tril-

lion proposal, the White House ini-

tially balked at providing billions

of dollars to fund coronavirus test-

ing and help federal health agen-

cies.

Since the early days of the pan-

demic, Mr. Romer has argued for a

wide-scale testing program, cost-

ing as much as $100 billion. He had

hoped to persuade Dr. Atlas that if

officials could quickly identify and

isolate people carrying the virus,

they would slow its spread and al-

low normal economic activity to

resume more quickly.

In his email, sent to Dr. Atlas’s

personal account, Mr. Romer pro-

posed additional testing and isola-

tion efforts that could allow far

more Americans to return to work

and shopping, generating eco-

nomic activity that would be 10 or

100 times larger than the cost of

the testing program itself.

In an interview, he said he also

“went out on a limb” to propose a

version of an expanded testing

plan that might appeal to Mr.

Trump, who said this year that he

had instructed federal officials to

slow the rate of testing because

“by having more tests, we have

more cases.”

Mr. Romer wrote that an in-

crease in positive test results

could be “interpreted as a sign of a

policy failure." He said the admin-

istration could instead consider a

plan to send Americans tests they

could administer themselves at

home, then allow people to volun-

tarily self-isolate if they tested

positive, which would not offi-

cially generate new “confirmed”

cases.

Dr. Atlas replied that the push

for such testing was the result of

“a fundamental error of the public

health people perpetrated on the

world.”

Mr. Romer said he was taken

aback by the answer: “Atlas just

responded in a way that just hon-

estly made it seem like he was in

over his head,” he said.

POLICY DEBATE

White House Opposes Expanded Virus Testing, Complicating Aid Talks

This article is by Jim Tankersley,
Noah Weilandand Emily Cochrane.

Since the early days of the pandemic, Paul Romer, a Nobel Prize-winning economist of New York

University, has been arguing for a wide-scale testing program, costing as much as $100 billion.

ALEX WELSH FOR THE NEW YORK TIMES

Katherine J. Wu contributed re-
porting from New York.

Screening the

asymptomatic is a

sticking point.