Covid-19 may damage
sperm quality and reduce fertility in men, according to a new study based on
experimental evidence.
The viral disease –
which has swept the globe, claiming nearly 2.2 million lives – can cause
increased sperm cell death, inflammation and so-called oxidative stress,
researchers reported on Friday in the journal Reproduction.
"These findings
provide the first direct experimental evidence that the male reproductive
system could be targeted and damaged by Covid-19," the authors concluded.
Experts commenting on
the research, however, said the capacity of the virus to compromise fertility
in men remains unproven.
Covid-19 causes
respiratory illness, especially in older people and those with underlying
medical problems.
The world has seen
more than 100 million confirmed cases since the disease emerged in central
China at the end of 2019.
Transmitted through
respiratory droplets, the disease attacks the lungs, kidneys, intestines and
heart.
It can also infect
male reproductive organs, impairing sperm cell development and disrupting
reproductive hormones, earlier studies have shown. The same receptors the virus
uses to access lung tissue are also found in the testicles.
But the effects of the
virus on the ability of men to reproduce remained unclear.
Behzad Hajizadeh
Maleki and Bakhtyar Tartibian from Justus-Liebig-University in Germany searched
for biological markers that might indicate a negative impact on fertility.
Analysis done at
10-day intervals for 60 days in 84 men with Covid-19 was compared to data for
105 healthy men.
In the Covid-19
patients, sperm cells showed a significant increase in markers of inflammation
and oxidative stress, a chemical imbalance that can damage DNA and proteins in
the body.
"These effects on
sperm cells are associated with lower sperm quality and reduced fertility
potential," said Maleki in a statement.
"Although these
effects tended to improve over time, they remained significantly and abnormally
higher in the Covid-19 patients."
The more severe the
disease, the bigger the changes, he added.
The male reproductive
system "should be considered a vulnerable route of Covid-19 infection and
declared a high-risk organ by the World Health Organisation," Maleki said.
Experts not involved
in the study welcomed the research, but cautioned that more was needed before
drawing hard and fast conclusions.
"Men should not
be unduly alarmed," noted Alison Campbell, director of embryology of the
CARE Fertility Group in Britain.
"There is
currently no definitive evidence of long-lasting damage caused by Covid-19, to
sperm or male reproductive potential," she told the London-based Science
Media Centre.
The results could have
been skewed, she added, by the fact that men recovering from Covid were treated
with corticosteroids and antiviral therapies, while the control group was not.
Allan Pacey, a
specialist in male reproductive medicine at the University of Sheffield, raised
a "stong note of caution" on how the data was interpreted.
Some of the indicators
of decreased sperm quality could be due to factors besides Covid-19, he said,
noting that more men in the Covid-19 group were overweight.
The simple fact that
only one group was very sick – no matter the cause – also needed to be taken
into account, he added.
"We already know
that a febrile illness can impact on sperm production, regardless of what
caused it." - AFP
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