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 Coronavirus does not threaten U.S. blood supply
Current guidelines for screening U.S. blood donors for symptoms of
COVID-19 and for a history of recent infections are effectively
protecting the blood supply from contamination with the new
coronavirus, researchers say. In a study conducted for the National
Institutes of Health, researchers tested nearly 18,000 "minipools"
of blood samples – that is, blood samples pooled from total of
roughly 258,000 donors from across the country. Only three minipools
contained genetic material from the virus, according to a report
published in the journal Transfusion. In all three, the viral levels
were low. In the one minipool that could be tested for infectivity,
the virus material was noninfectious, the researchers said. "Other
studies have shown that in rare cases where a blood sample tested
positive, transmission by blood transfusion has not occurred,"
coauthor Sonia Bakkour of the University of California, San
Francisco, said in a statement. "Therefore, it appears safe to
receive blood as a transfusion recipient and to keep donating blood,
without fear of transmitting COVID-19 as long as current screenings
are used." (https://bit.ly/3iblpG9)
High vitamin D levels do not protect against COVID-19
Low levels of vitamin D have been tied to higher risks for COVID-19
and more severe illness, although no studies have proved that
vitamin D deficiency is actually to blame. A study published on
Tuesday in PLoS Medicine suggests that boosting vitamin D levels
with supplements would not help. Researchers studied more than 1.2
million people of European ancestry from 11 countries, some of whom
had genetic variants that result in naturally higher levels of
vitamin D. People with these variants did not have a lower risk for
coronavirus infection, hospitalization, or severe COVID-19, the
researchers reported. Their results suggest that boosting vitamin D
levels in deficient people probably would not help combat the
coronavirus, and they do not believe randomized trials testing
vitamin D supplementation would be worthwhile. Other experts,
however, would still like to see such trials, especially in people
of African and other non-European ancestries. (https://bit.ly/3g62hqA)
Immune system workaround helps blood cancer patients with COVID-19
In blood cancer patients who lack antibody-producing cells, other
immune cells can compensate to help fight the coronavirus, new
research shows. People with blood cancers – such as leukemia,
lymphoma, and myeloma - often lack antibody-making immune cells
called B cells, particularly after treatment with certain
medications. Without enough B cells and antibodies, they are at risk
for severe COVID-19. But other immune cells, called T cells, learn
to recognize and attack the virus, according to a report published
in Nature Medicine.
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 Blood cancer patients in
the study were more likely to die from COVID-19
than patients with solid tumors or without
cancer. But among the blood cancer patients,
those with higher levels of CD8 T cells were
more than three times more likely to survive
than those with lower levels of CD8 T cells. The
authors speculate that CD8 T cell responses to
COVID-19 vaccines might protect blood cancer
patients even if they do not have typical
antibody responses. "This work can help us
advise patients while we wait for more vaccine
specific studies," said co-author Dr. Erin Bange
of the University of Pennsylvania in a
statement. While patients' vaccine response
"likely will not be as robust as their
friends/family who don't have blood cancers, it
is still ... potentially lifesaving," Bange
added. (https://go.nature.com/2STOVWf)
In some long COVID cases, air gets trapped in
lungs
Some COVID-19 survivors with persistent
breathing symptoms have a condition called "air
trapping," in which inhaled air gets stuck in
the small airways of the lung and cannot be
exhaled. Researchers studied 100 COVID-19
survivors who were still having respiratory
problems, like coughs and shortness of breath,
an average of more than two months after their
diagnosis. Overall, 33 had been hospitalized,
including 16 who had needed intensive care. The
amount of lung area showing so-called
ground-glass opacities on imaging studies – a
typical sign of lung damage from COVID-19 – was
higher in the hospitalized group than in those
with milder disease, and it was even higher in
patients who had required intensive care.
COVID-19 severity made little difference in the
average percentage of lung affected by air
trapping, however. It was 25.4% in patients not
hospitalized, 34.5% in those who were
hospitalized without intensive care, and 27.2%
in patients who had been critically ill. By
comparison, that proportion was 7.3% in a group
of healthy volunteers. The air trapping was
largely confined to patients' narrowest airway
passages, according to a report posted on
Saturday on medRxiv ahead of peer review. "The
long-term consequences" of these patients' small
airways disease "are not known," the authors
said. (https://bit.ly/3pcekXo)
Open https://tmsnrt.rs/3c7R3Bl in an external
browser for a Reuters graphic on vaccines in
development.
(Reporting by Nancy Lapid; Editing by Bill
Berkrot)
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