science.org SCIENCEPHOTO: FABIAN BIMMER/REUTERS2016 in Nigeria’s Borno state. The continent
is still battling big outbreaks of vaccine-
derived polio, however, which occur in areas
of low immunization when the live but
attenuated virus in the oral polio vaccine
regains its ability to paralyze and spread.
The Global Polio Eradication Initiative is
hopeful that it can stop the spread of the
virus in Malawi quickly through a vaccina-
tion campaign, as it has done for several
other “imported” wild polio outbreaks.Winter study probes Great Lakes
ECOLOGY | Researchers from the United
States and Canada last week used sleds,
snowmobiles, airboats, and icebreakers to
fan out across the Great Lakes in a bid to
better understand how the five water bodies
function in the dead of winter and how cli-
mate change is reshuffling their ecosystems.
Scientists from 19 research institutions and
government agencies participated in the
Winter Grab, a weeklong push to collect
data at some 30 sampling sites. Fewer than
5% of Great Lakes studies have been done
in winter, in part because lakes were long
considered relatively dormant when covered
by ice—not to mention dangerous to access.
As a result, scientists know relatively little
about how lake organisms behave dur-
ing winter or how nutrient cycles vary by
season. As warmer winters shrink ice cover,
Winter Grab researchers hope their findings
will help spur more efforts to study lakes
around the world during the coldest months.Dinosaurs’ death came in spring
PALEONTOLOGY | The beginning of the end
for dinosaurs was likely one day in spring,
according to a study of fish fossils excavated
in North Dakota. To pinpoint the season of
the Cretaceous-Paleogene mass extinction
66 million years ago, paleontologists analyzed
the bones of filter-feeding fish from a site
called Tanis. There, the asteroid impact that
doomed dinosaurs kicked up a large river
wave, burying countless late-Cretaceous era
animals and plants. The fish had debris from
the impact lodged in their gills, evidence
that they had perished within minutes. The
researchers used carbon isotopes in the
bones to identify seasonal growth layers.
(The fish grew faster in spring, when foodNEWS
“
[Hong Kong’s] hospitals are
sandcastles in a tsunami.
”
University of Hong Kong virologist Siddharth Sridhar, in a tweet describing
the impact of the recent COVID-19 surge on the city’s health care system.The presidents of Ghana, Rwanda, and Senegal visited a modular vaccine lab in Germany.COVID Africa builds mRNA vaccine capacity
IN BRIEF
Edited by Kelly ServickT
he drive to help African countries produce vaccines with messenger
RNA (mRNA) technology got big boosts last week from the World
Health Organization (WHO) and the company BioNTech. The suc-
cess of mRNA COVID-19 vaccines made by the Pfizer-BioNTech col-
laboration and Moderna led to intense global demand, but African
countries have had little access because of limited supply and
high prices. Campaigns by several governments and nongovernmental
organizations failed to convince the companies to freely share their
technologies with economically strapped countries. So last year WHO
launched a hub in South Africa to produce mRNA vaccines indepen-
dently. The agency, which hopes the hub licenses a product by 2024,
last week announced plans to train scientists from South Africa, Egypt,
Kenya, Nigeria, Senegal, and Tunisia. BioNTech, which has been criti-
cized for trying to undermine the WHO effort, separately announced
that later this year it will train local scientists and send modular, ship-
ping container–size vaccine factories to Ghana, Rwanda, and Senegal.Wild poliovirus back in Africa
INFECTIOUS DISEASE | In a setback for
the global polio eradication campaign, a
wild poliovirus has leapt from Pakistan
to the African continent, where it has
paralyzed a 3-year-old girl in Malawi. The
case, announced on 17 February by theMalawi government, is the first wild polio
case in the country since 1992. Pakistan
and Afghanistan are the last two countries
that are endemic for the wild virus, which
means circulation there has never stopped.
Occasionally, however, the virus spills over
from these entrenched reservoirs. Africa’s
last known case of wild polio occurred in798 25 FEBRUARY 2022 • VOL 375 ISSUE 6583