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 Possible "missing link" found in virus reproduction cycle
Researchers may have found a missing link in the coronavirus
reproduction cycle that could potentially be targeted by drugs,
according to a report in Science on Thursday. Scientists already
knew that once the virus breaks into a cell, it forms
double-membrane sacs, or vesicles, in which it makes copies of its
genetic material. But the sacs appeared to be closed and it was
previously unclear how the genetic material moved from the sac into
the fluid in the cell, where new virus particles assembled
themselves. Eric Snijder of Leiden University Medical Center and his
colleagues discovered tiny channels through both membranes that are
wide enough to let the genetic material pass through. "In electron
microscope images we can see 'stuff' sticking out of these channels.
Most likely this 'stuff' is the viral RNA on its way out, but as the
sample is frozen, there is no movement and we still need to find
ways to properly identify the 'stuff' as viral RNA," Snijder told
Reuters. "Blocking this channel somehow...could create a big problem
for the virus to do its tricks," he added. (https://bit.ly/2Xy4UZN)
Data suggest safety, benefit of non-COVID vaccines
Two new studies found that people who had received vaccines for
other viruses developed fewer or less serious coronavirus
infections, though more research is needed to determine their
potential effectiveness against COVID-19. According to a study
published in Cell Reports Medicine on Wednesday, people who received
the BCG tuberculosis vaccine in the last 3 years did not developed
more severe coronavirus infections. "Results of the prospective BCG
trials currently ongoing are needed before definitive conclusions
can be drawn," said coauthor Mihai Netea of Radboud University
Medical Center. A separate study from the Mayo Clinic, posted online
ahead of peer review, found that people who received other vaccines
in the past 5 years - such as against flu, pneumonia, or hepatitis -
had lower coronavirus infection rates. Netea said the Mayo Clinic
report suggests the "beneficial effects of vaccines may be broader
than currently known" and that his team had seen similar data on flu
vaccines. (https://bit.ly/3fDzwPu; https://bit.ly/2DDlQXD)
Graphic: Vaccines and treatments in development
https://graphics.reuters.
com/HEALTH-CORONAVIRUS/
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Viral loads high in patients without symptoms
Asymptomatic COVID-19 patients can carry high loads of the new coronavirus in
their nose, throat and lungs, and the loads tend to decrease more slowly than in
patients who show symptoms, according to a report in JAMA Internal Medicine on
Thursday.
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The researchers studied 303 young and otherwise healthy patients isolated in a
community treatment center in the Republic of Korea. Roughly a third had no
symptoms when they were diagnosed, and about 20% of this group developed
symptoms while isolated. Multiple tests over the course of about a month showed
similar viral loads in people with or without symptoms. The tests could not
distinguish active, or infectious, virus particles from inactive particles. "For
a better understanding of the viral shedding and potential transmissibility of
asymptomatic infection, large rigorous epidemiologic and experimental studies
are needed," the researchers wrote. (https://bit.ly/30zjthC)
U.S. cancer detection rates dropped during pandemic
The average number of weekly diagnoses of six common types of cancer in the
United States fell by 46% in the early stages of the pandemic, according to new
data in JAMA Network Open. Researchers led by Dr. Harvey Kaufman of Quest
Diagnostics studied more than 278,000 patients with new diagnoses of breast,
colorectal, lung, pancreatic, gastric, or esophageal cancer from the beginning
of January through mid-April. In January and February, an average of 4,310 new
cancers were diagnosed weekly, they reported. After March 1, weekly diagnoses
fell between 25% and 52%. "Some cancers grow very slowly but others grow a
little bit faster and these delays can be significant for some patients,"
Kaufman said. The American Society of Clinical Oncology (ASCO) has recommended
cancer screening that requires in-person visits be postponed during the
pandemic. But this is not a blanket statement, ASCO's chief medical officer, Dr.
Richard L. Schilsky, told Reuters. "Those are decisions that have to be weighed
between the doctor and the patient," he said, adding that they must take into
account the patient's cancer risk, as well as the likelihood of exposure to
COVID-19. (https://bit.ly/3ibcIZb)
(Reporting by Nancy Lapid and Anne Harding; Editing by Tiffany Wu)
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