By Nancy Lapid (This September 21 story corrects link to source material in second item)
(Reuters) - The following is a roundup of some
of the latest scientific studies on the novel coronavirus and efforts to find
treatments and vaccines for COVID-19, the illness caused by the virus.
COVID-19 may damage immune cells in the bone
marrow
Even bone marrow may not be a safe harbor from
the ravages of COVID-19, according to a study that found previously
unrecognized changes in newly produced immune cells, called monocytes, released
into the blood from bone marrow. To learn more about how the body responds to
COVID-19, researchers obtained serial "snapshots" of patients' immune
health by analyzing their immune cells at multiple points during their hospital
stays. In COVID-19 patients with more severe disease, the monocytes do not
function properly, researchers reported last week in Science Immunology. It was
not yet clear whether the monocytes are being released from the bone marrow in
an altered state or whether the alterations happen after monocytes enter the
blood, coauthor Tracy Hussell of the University of Manchester in the UK told
Reuters. Either way, she said, treatments that prevent their release from the
bone marrow may help reduce the exaggerated immune response that contributes to
poor outcomes in patients with severe COVID-19. (bit.ly/3mziJls)
COVID-19 reinfections occur, but remain rare
Another case of reinfection after recovery
from COVID-19 has been reported, this time in a healthy young military
healthcare provider at a U.S. Department of Defense hospital in Virginia. He
was first infected by a patient in March. He recovered within 10 days and
"returned ... to excellent health," his doctors reported on Saturday
in Clinical Infectious Diseases. Fifty-one days later, he was reinfected by a
household member. Genetic studies showed the first and second infections to be
from slightly different strains of the virus. The reinfection made him sicker,
perhaps because the second strain was more potent, or the household contact
infected him with a higher load of virus, doctors said. It was also possible
antibodies from the first infection may have triggered his immune system to
respond more strongly to the virus the second time his body encountered it.
COVID-19 reinfections are still rare, they said. Kristian Anderson, professor
of immunology and microbiology at Scripps Research in La Jolla, California,
recently told Reuters virus reinfections are always possible. "We don't
know at what frequency reinfections (with the new coronavirus) occur and how
that might change over time," Anderson said. Without further studies,
"we can't conclude what a single case of reinfection means for longevity
and robustness of COVID-19 immunity and relevance for a future vaccine,"
she added. (bit.ly/2RN3FT0)
Proven immunotherapy approach might be
possible in COVID-19
A proven approach to severe virus infections,
known as cytotoxic T cell therapy, may be applicable to COVID-19 despite a
potential hurdle, researchers said. The approach involves treating critically
ill patients with infusions of key immune cells known as T-lymphocytes obtained
from people who successfully fought off the same virus. These donor T cells
have learned to recognize and target the invading virus. But steroids, which
are being increasingly used to treat COVID-19 patients, are toxic to
lymphocytes, likely canceling out any beneficial effects of the immunotherapy.
In a new report posted on bioRxiv ahead of peer review, researchers describe a
possible workaround. They say they have figured out a way to take donor T cells
that target the novel coronavirus and make them resistant to the deadly effects
of steroids. "We are currently working on ... developing clinical trials
to determine safety and efficacy," coauthor Dr. Katy Rezvani of The
University of Texas MD Anderson Cancer Center told Reuters. (bit.ly/3hNL83x)
High COVID-19 mortality seen in
assisted-living facilities
Data compiled from more than 4,600 assisted
living facilities in seven U.S. states through the end of May showed a
four-fold higher COVID-19 fatality rate than in the nearby communities,
researchers reported on Monday in the Journal of the American Geriatric
Society. In North Carolina and Connecticut, for example, the proportions of
COVID-19 cases that were fatal across the state were 3.3% and 9.3%,
respectively. In assisted living facilities in those states, the fatality rate
climbed to 13% and 31.6%. Unlike nursing homes, assisted living communities are
not subject to federal regulation and are not required to collect and report
data on COVID-19, coauthor Helena Temkin-Greener of the University of Rochester
School of Medicine & Dentistry said in a news release. In this study, and
in a separate study of nursing homes her team published on Monday in the same
journal, COVID-19 cases were more common in facilities with more minority
residents and more residents with dementia, chronic obstructive pulmonary
disease, and obesity. "Assisted living communities and their residents
urgently need local, state, and the federal governments to pay at least the
same level of attention as that given to nursing homes," Temkin-Greener
and colleagues conclude. (bit.ly/3iUaApI; bit.ly/3cjjVEN)
Open tmsnrt.rs/3a5EyDh in an external browser for a
Reuters graphic on vaccines and treatments in development.
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