FOR BREAKING NEWS VISIT WWW.QNS.COM JUNE 18, 2020 • HEALTH • THE QUEENS COURIER 35
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REUTERS/Andrew Kelly
Summer may slow coronavirus but is unlikely to stop it
BY KATE KELLAND, MANAS MISHRA
AND CHRISTINE SOARES
Reuters
Th e arrival of warmer weather in the
Northern Hemisphere raises the question
of whether summer could slow the spread
of the coronavirus outbreak. Here is what
science says.
While warmer weather typically ends
the annual fl u season in temperate
zones, climate alone has not stopped the
COVID-19 pandemic from sweeping any
part of the globe. In fact, outbreaks in hot
and sunny Brazil and Egypt are growing.
Still, recent data about how sunlight,
humidity and outdoor breezes aff ect the
virus gives some reason for optimism that
summer could slow the spread.
IS THE NEW CORONAVIRUS
‘SEASONAL?’
Th e virus has not been around long
enough to be certain. Respiratory infections
like fl u and the common cold follow
seasonal patterns in temperate regions.
Environmental conditions including cold
weather, low indoor humidity, and spending
more time indoors can all hasten the
spread of an epidemic. Real-world evidence
about the eff ect of weather on the
new virus is mixed.
One study of 221 Chinese cities found
that temperature, humidity and daylight
did not aff ect speed of spread. Two
other studies did fi nd an eff ect, including
a look at new infections in 47 countries
that linked higher temperatures to
slower transmission in places like the
Philippines, Australia and Brazil.
“Th e Northern hemisphere may see a
decline in new COVID-19 cases during
summer and a resurgence during winter,”
concluded the authors of another study
of 117 countries, which found that each
1-degree of latitude increase in distance
from the Equator was associated with a
2.6 percent increase in cases.
The head of the World Health
Organization’s Emergencies Programme,
Mike Ryan, cautioned: “We cannot rely
on an expectation that the season or the
temperature will be the answer to the disease’s
spread.”
WHY DO RESPIRATORY DISEASES
SPREAD DIFFERENTLY IN SUMMER
AND WINTER? “Th e reason why cold
weather is presumed to cause spreading of
coughs, colds and fl u is that cold air causes
irritation in the nasal passages and airways,
which makes us more susceptible
to viral infection,” said Simon Clarke, an
expert in cellular microbiology at Britain’s
University of Reading.
Winter weather tends to inspire people
to spend more time indoors, although air
conditioning may also bring people back
inside in the summer.
In the lab, when temperatures and
humidity rise, coronavirus particles on
surfaces more quickly lose their ability to
infect people — and they are inactivated
especially fast when exposed to sunlight,
U.S. government researchers found.
It is still a good idea for people to
wash hands frequently, practice social
distancing and wear a mask in summer,
experts say. While virus particles coughed
or exhaled by an infected person will
disperse faster outdoors, one study found
a gentle breeze could carry saliva droplets
up to 6 m (19.69 feet).
WHAT ELSE ABOUT SUMMER
COULD SLOW THE VIRUS?
Vitamin D: Researchers are investigating
whether levels of immunity-regulating
vitamin D in people’s blood aff ect
how vulnerable they are to infection with
the new coronavirus or how sick they
become.
Th e majority of vitamin D in the body
comes from skin exposure to sunlight.
Pollen: A study in the Netherlands of
all “fl u-like” illnesses, including COVID-
19, in recent years concludes that pollen
concentrations are a better predictor than
sunlight of respiratory disease trends.
Clouds of pollen act as air fi lters, snagging
virus particles, and pollen activates
immune responses, even in people without
overt allergies. Th e study found that
fl u-like illness started to drop when pollen
in the air reached 610 grains per cubic
meter, a typical level from early spring to
October in most middle latitudes.
/WWW.QNS.COM
