704 18 FEBRUARY 2022 • VOL 375 ISSUE 6582 science.org SCIENCEing maskless just seems egregious.” Indeed,
the U.S. Centers for Disease Control and
Prevention has held firm in recommending
masks for indoor public spaces in areas of
high transmission—which is nearly all of
the country.
“I do feel it is on the early side” to lift
indoor mask requirements in most states,
says Emory University epidemiologist Jodie
Guest—though recommendations may be
a better option than requirements as case
numbers plummet, she adds.
Still, with the United States logging more
than 2000 daily deaths last week, “We can-
not say we are at a level that’s tolerable to
live with this virus,” Guest says. Her team
has been developing rough guidelines for
when a true endemic stage of COVID-19 has
been reached: daily case rates below 30 per
100,000, ICUs below 80% of capacity, vacci-
nation rates of at least 75%, and fewer than
100 COVID-19 deaths a day nationwide.
Deciding when to end
mask requirements in schools
is especially difficult, in part
because of continued (but
hard to prove) concerns the
coverings impede learning
and social development. “If
you ask a bunch of scientists,
‘Should kids wear face masks
in school?’ you’re probably
going to get a lot of disagree-
ment,” Andersen notes, “and
I don’t know who is right.”
Guest says she doesn’t
have as clear a sense of the
numerical thresholds that
could determine when schools should stop
mandating masks. “I would be hesitant [to
remove requirements] right now,” she says,
adding the step could soon be justified in
parts of the country.
Data to inform such debates may become
less available or reliable if governments pivot
too soon to an endemic view of the corona-
virus, scientists say. As pandemic restrictions
in Denmark relax, “people are becoming less
motivated to get tested and we are beginning
to downscale our test system,” Petersen says.
Some governments are limiting ef-
forts to find and report cases. Sweden,
long an outlier among European coun-
tries for its laissez-faire approach to the
pandemic, ended widespread testing at
mobile centers as cases declined from
their Omicron peak. The United King-
dom is reportedly weighing ending free
public testing for the virus in the coming
weeks. Meanwhile, the Canadian prov-
ince of Saskatchewan last week switched
from providing daily to weekly reports of
COVID-19 cases. And Tennessee last month
joined several states already reporting case
counts weekly. “Daily case counts matter,”
Guest says. “Every time I lose the ability to
have a number, it makes me nervous.”
Official counts are already becoming less
meaningful as the reliance on at-home test
increases, making other surveillance ap-
proaches all the more important. Last week,
researchers took to Twitter in outrage after
a U.K. news report claimed the United King-
dom might not continue to fund a long-
running study in which the Office for Na-
tional Statistics (ONS) conducts repeated
antibody surveys and SARS-CoV-2 testing of
more than 100,000 randomly selected house-
holds. “What that’s meant is that you’ve
had a way of seeing the prevalence in your
population that does not depend on people
accessing testing,” says Christina Pagel,
a health services researcher at University
College London.
Discontinuing the ONS study would also
obscure data on asymptomatic cases, dif-
ferences in disease burden
between different ethnic and
occupational groups, and the
impact of Long Covid, Pagel
says. She suspects the outcry
will sway the U.K. govern-
ment, which responded in
the news report by saying
no funding decision had
been made and it “obviously”
wanted to “maintain our
world-leading surveillance
capacity” for COVID-19.
But in the growing num-
ber of “back to normal”
messages, Pagel sees lead-
ers ignoring obvious next steps to protect
public safety. Even researchers who aren’t
speaking up to defend specific restrictions
are urging governments to step up their
COVID-19 fight, rather than scale it back.
They want aggressive new pushes to reach
the unvaccinated, distribute rapid tests, and
make COVID-19 treatments much more ac-
cessible, for example. “Frankly, I don’t re-
ally think that 2 to 3 weeks more of a mask
mandate is going to make much difference
in the long run,” says KJ Seung, a health
policy adviser at Partners In Health. “More
alarming to me is that our public health
system doesn’t seem to have any plan for
dealing with the next surge.”
“I don’t particularly want to be in a fu-
ture where I get COVID twice a year,” Pagel
adds. Averting that future may mean ad-
aptations such as technologies to improve
indoor air quality and strong virus surveil-
lance that can be ramped up at the first
sign of another surge. “Why would we not
make that effort?” she wonders. “It’s almost
like having that conversation is considered
a failure.” j“More alarming to
me is that
our public health
system doesn’t
seem to have
any plan for dealing
with the next surge.”
KJ Seung,
Partners In HealthNEWS | IN DEPTH
F
ish genetically engineered to glow
blue, green, or red under blacklight
have been a big hit among aquarium
lovers for years. But the fluorescent
pet is not restricted to glass displays
anymore. The red- and green-glowing
versions, more vivid than normal zebra-
fish even in natural light, have escaped fish
farms in southeastern Brazil and are mul-
tiplying in creeks in the Atlantic Forest, a
new study shows. It is a rare example of
a transgenic animal accidentally becoming
e s t a b l i s h e d i n n a t u r e , a n d a c o n c e r n f o r b i o -
logists, who worry the engineered exotic
fish could threaten the local fauna in one
of the most biodiverse spots on the planet.
“This is serious,” says ecologist Jean
Vitule at the Federal University of Paraná,
Curitiba. Vitule, who was not part of the
research, says the ecological impacts are
unpredictable. He worries, for example,
that the fluorescence-endowing genes
from the escapees could end up being in-
troduced in native fish with detrimental
effects, perhaps making them more visible
to predators. “It’s like a shot in the dark,”
he says.
The unwelcome visitors are well known
to scientists who have used zebrafish (Da-
nio rerio) for developmental and genetic
studies for decades. Native to Southeast
Asia, the match-size freshwater fish were
engineered to glow for research purposes
in the late 1990s by endowing them with
genes from fluorescent jellyfish (for blue
and green colors) and coral (for red). In
the 2000s, companies saw the potential
of the neon fish as pets. Trademarked as
Glofish, they became the world’s first ge-
netically engineered species to be commer-
cially available.Transgenic
fish invades
Brazilian
streams
Fluorescent aquarium
curiosity has escaped from
fish farms and may
threaten local biodiversity
ECOLOGYBy Sofia Moutinho