The Week - USA (2021-03-05)

Health & Science NEWS 23^

Kids are half as susceptible...
People under age 20 may be almost half as
susceptible to coronavirus as their elders—
and less likely to transmit the disease to
others. That’s the conclusion of a new
Israeli study, which fitted statistical mod-
els of transmission to a data set of Covid
testing results from 637 households. The
researchers calculated that under-20s were
43 percent as susceptible as those over 20,
and 63 percent as likely to spread the virus
to others. They also found that children
were more likely to receive a negative PCR
test result despite being infected, suggest-
ing they have a lower viral load. Lead
researcher Itai Dattner, from the University
of Haifa, tells ScienceDaily.com that under-
standing children’s role in transmission is a
“top priority” for efforts around the world
to reopen or keep open schools. Why
children aren’t as affected remains unclear.
But another study has quashed the theory
that it is because they are more likely than
adults to have antibodies to common-cold
coronaviruses. On analyzing those anti-
bodies, University of Pennsylvania research-
ers found that they neither disarmed the
virus nor mitigated its symptoms.

...But MIS-C cases are rising
Doctors across the country have been see-
ing a significant increase in the number of
chil dren sickened with a dangerous syn-

drome linked to the coro na virus, The New

York Times reports. The syndrome, called

multi system inflam ma tory syn drome in

children, or MIS-C, remains rare: The Cen-

ters for Disease Con trol has recorded 2,060

cases in 48 states, Puer to Rico, and the

District of Colum bia, including 30 deaths.

The median age of those affected was 9.

But the data show cases climbing since mid-

October, and doctors say more of MIS-C

patients require treatment in the intensive-

care unit. “A higher percentage of them

are really critically ill,” said Dr. Roberta

DeBiasi, chief of infectious diseases at Chil-

dren’s Na tional Hos pi tal in Wash ing ton,

D.C. Symptoms—which seem to be con-

nected to coro na virus infections—start with

fever, rash, red eyes, and gastrointestinal

problems, and can progress to heart dys-

func tion. Most of the affected kids survive,

but doctors do not know if they will suf-

fer lingering health problems in coming

months or years. It’s unclear why MIS-C

cases are rising, but it may correspond to

the overall surge in coro na virus cases after

the holidays.

A drug to fight obesity

In what scientists say is a “game changer”

for obesity, an appetite- suppressing drug

has helped people lose up to 20 percent of

their body weight. The treatment, semaglu-

tide, is already used for type 2 diabetes. It

is a synthetic version of GLP-1, a naturally

occurring hormone released by the body

after a filling meal. In a new trial involv-

ing 2,000 people in 16 countries, scientists

administered a much higher dose of sema-

glutide to people wanting to lose weight.

Over 15 months, the participants who

received the drug lost an average of almost

15 percent of their body weight compared

with only 2.4 percent for those who got a

placebo. Almost a third of recipients lost

20 percent of their weight. Those who lost

weight also saw substantial reductions in

risk factors for heart disease and diabetes,

such as high blood-pressure and blood-

sugar levels. Lead author Robert Kushner,

from Northwestern University, tells The

New York Times the findings mark “the

start of a new era of effective treatments

for obesity.”

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The virus is less likely to infect them.

After a nearly seven-month, 293-million-

mile journey—with a heart- stopping final

descent—NASA’s Perseverance rover

safely landed on Mars last week to begin

a new search for signs of past Martian life.

The $2.7 billion, car-size explorer is fitted

with an array of sophisticated equipment—

including cameras, lasers, and ground-

penetrating radar—that scientists hope will

find chemical evidence of fossilized micro-

bial life. Project scientist Ken Farley tells

The Wash ing ton Post that the mission—the

most ambitious yet of NASA’s 20 trips

to the Red Planet—will “really make the

first step in answering the question of

whether life exists elsewhere.” If there is

proof that microbes arose on Mars billions

of years ago, when it was warmer and

wetter, it will strongly suggest we are not

alone in the universe. The vehicle carrying

Perseverance entered the Martian atmo-

sphere at 12,000 mph and decelerated

using a 70-foot-diameter parachute and

rocket thrusters. Then a “sky crane” low-

ered the rover into the Jezero crater—the

site of an ancient Martian lake. Because

of the 11- minute signal delay between

Earth and Mars, the whole process was

autonomous. After some equipment tests,

Perseverance will attempt a first: launching

a tiny solar- powered helicopter, Ingenuity,

into the thin Martian atmosphere. The

rover will then trundle over to the old

lake’s delta to begin its search in earnest.

Perseverance begins its search for life

Actual image of the rover being lowered to Mars

Scientists broadly agree

that a large extraterres-

trial object slammed into

Earth 66 million years

ago, wiping out the dino-

saurs. But a new study

proposes that instead of

an asteroid, the planet

was bombarded by

high-speed chunks of an

icy comet that broke apart when it flew

too close to the sun. The researchers,

from Harvard, argue that Jupiter’s grav-

ity pulled a comet into the solar system

and then slung it toward the sun. They

say that when this unfortunate comet

was then torn asunder by solar forces, it

could have produced enough

shards—of the right size, rate,

and trajectory—to cause

the cataclysm that wiped

out the dinosaurs. They

note that the impactor

was composed of car-

bonaceous chondrites, a

rocklike material found

in only 10 percent of

asteroids. Many scientists

aren’t buying it. They say

the study overestimates how often com-

ets are pulled apart by the sun, and that

the shards wouldn’t do enough damage.

But co- author Amir Siraj insists that what

type of space rock created the Chicxulub

crater in the Yucatan Peninsula in Mexico

remains “an open question.”

A very bad day for the dinosaurs

Was the dinosaur-destroyer a comet?