Days
before a global rollout kicks off with the President of Indonesia receiving the
Sinovac Biotech Ltd. vaccine on live
television, uncertainty swirls over the efficacy of the leading Chinese shot,
for which four different protection rate numbers have been released in recent
weeks.
Indonesia, which is moving the fastest on distributing the
Sinovac shot to its population, said that a local trial showed an
efficacy of 65% against Covid-19. But only 1,620 people in Indonesia took part
in that trial -- too small for meaningful data.
Turkey said last month that the same
vaccine showed efficacy of 91.25% in its local trial, which was similarly too
small to draw a sufficient conclusion.
In Brazil, where Sinovac’s biggest trial of more than
13,000 people is being conducted, dueling efficacy rates have been publicized.
The company’s local trial partner, Butantan Institute, said last week that the
vaccine was 78% effective in preventing mild cases of Covid-19 and 100%
effective against severe and moderate infections.
Yet on Tuesday, Butantan said the overall rate, which also
includes very mild cases that didn’t require medical help, is actually 50.38%.
Overlapping efficacy data is not unprecedented in the
Covid-19 vaccine race -- AstraZeneca Plc released two separate protection rates
based on different dosage regimes last month -- and all the findings are above
the threshold of 50% efficacy required by regulators for approval.
Yet the confusion, which comes as several governments
commit to inoculating their citizens with Sinovac’s shot, is fueling skepticism over Chinese vaccines,
which have disclosed less safety and testing information than western
front-runners. The data kerfuffle risks further undermining trust in shots that
President Xi Jinping has promised to share with the rest of the world as a
global public good.
“There is enormous financial and prestige pressure for
these trials to massively overstate their results,” said Nikolai Petrovsky, a
professor at the College of Medicine and Public Health at Flinders University.
“In many cases, such overstatements are also politically
motivated, as countries that have failed to properly control the pandemic now
want to overstate the benefits of the vaccines to win votes and appease local
unrest.”
A Sinovac spokesman declined to comment on the numbers from
its trials in Brazil, Turkey and Indonesia and said more data would be released
by its Brazil partner this week.
The data issue appears to already be holding up regulatory
approval for Sinovac’s vaccine in some places.
“Initially, Sinovac was going to ship the vaccine supply to
Hong Kong in January. But they delayed the announcement of the Phase III
clinical trial data three times,” said David Hui, a professor of respiratory
medicine at the Chinese University of Hong Kong who sits on the Asian financial
hub’s Covid-19 advisory panel. “That would delay the assessment of their
application.”
Calculation
Confusion The massive Brazil trial, which Sinovac has said will be
where it gets its definitive efficacy data, has received intense scrutiny.
Observers were flummoxed by the first efficacy rate of 78%
announced by Butantan Institute. According to the information disclosed, the
trial saw about 220 participants infected: 160 in the placebo group and almost
60 in the vaccinated group.
If trial participants were evenly split between the vaccine
and placebo group, then the efficacy rate should come out to 62.5%, said
Petrovsky, who’s also a research director for Vaxine Pty Ltd., a company that
is developing a Covid-19 vaccine.
External calculations remain speculative unless more data,
like the total number of people in the placebo group and vaccinated group, is
released in peer-reviewed scientific journals, said Raina MacIntyre, head of
the Biosecurity Program at the Kirby Institute at the University of New South
Wales.
Overall Efficacy of Sinovac Vaccine in
Brazil Just Above 50%
On Tuesday, Butantan explained the 78% was calculated
considering the mild, moderate and severe cases, officials said. When very mild
cases are included among the 13,000 volunteers, the figure is 50.4% -- 167
infected volunteers in the placebo arm, and 85 in the vaccine arm. The shot
proved 100% effective in preventing severe cases.
Brazilian health regulator Anvisa requested additional data
from the Butantan Institute on the Sinovac trial before deciding whether to
approve the vaccine for use.
https://www.bloomberg.com/news/articles/2021-01-12/china-vaccine-going-global-with-four-different-efficacy-rates
COVID-19 severity linked to gut
bacteria in first-of-its-kind study By Rich Haridy January 11, 2021
A
first-of-its-kind study has investigated the relationship between COVID-19
severity and the gut microbiome. The observational research suggests specific
microbial patterns correlate with disease severity and those bacterial
imbalances may account for some cases of “ long COVID ”.
A
growing body of
study is finding a relationship between our immune system
and the massive population of bacteria living in our intestines, known as our
gut microbiome. These links suggest our microbiome may
influence , or be influenced by, inflammatory activity in the
body. And this relationship could play a role in everything from depression and obesity to Alzheimer’s .
In light of these recent microbiome discoveries it is
reasonable to wonder what kind of influence gut bacteria has on perhaps the
greatest acute health crisis of our time, COVID-19. A handful of preliminary
studies published in late 2020 suggested patients suffering from COVID-19 may
present with novel gut microbiome signatures.
One
study found COVID-19 patients presented with unique microbial compositions
compared to patients with influenza and healthy controls. Another small pilot study , investigating a cohort of just
15, suggested there may be signs microbiome alterations correlate with COVID-19
severity.
This new study, published in the BMJ
journal Gut , offers the most detailed investigation to date into the
relationship between COVID-19 severity, the gut microbiome, and general
inflammatory biomarkers. The research looked at blood and stool samples from
100 COVID-19 patients admitted to hospital, compared to 78 healthy control
subjects.
The study found significant
microbial differences between COVID-19 patients and controls. Species including
Bifidobacterium adolescentis , Faecalibacterium prausnitzii and Eubacterium
rectale , which have previously been shown to play a role in immune system
activity, were all seen in notably lower volumes in COVID-19 patients. COVID-19
patients also displayed unusually higher volumes of bacterial species including
Ruminococcus gnavus, Ruminococcus torques , and Bacteroides dorie .
“Moreover, this perturbed
composition exhibited stratification with disease severity concordant with
elevated concentrations of inflammatory cytokines and blood markers such as C
creative protein, lactate dehydrogenase, aspartate aminotransferase and
gamma-glutamyl transferase,” the researchers report in the study.
A smaller subset of COVID-19 patients in the study were
followed for up to a month after recovery and discharge from hospital,
revealing the disrupted microbiome signatures seemed to persist beyond the
phase of acute disease. One hypothesis raised by the researchers suggests
microbiome disruptions could play a role in the enduring
symptoms many COVID-19 patients suffer from in the months following
infection.
It is important to note these findings are very preliminary
and cannot offer insight into causality. It’s unclear, for example, whether
these particular COVID-19 patients had irregular microbiome signatures before
viral infection. And it is unclear whether these microbiome signatures directly
influence the severity of the disease, or are merely a consequence of it.
“… the observed gut microbiota composition could simply be
a response to patients’ health and immune states rather than a direct
involvement in disease severity, as such it may not be directly applicable to
predicting disease susceptibility in non-COVID-19 subjects,” the researchers
note in the new study.
Perhaps the most interesting hypothesis to come out of this
preliminary study is the proposition that some kind of personalized microbiome
therapy could be a useful treatment for patients following the acute phase of
COVID-19. A great deal of work is still needed, however, before any kind of
real-world clinical application arises from this field of investigation.
More
https://newatlas.com/health-wellbeing/gut-bacteria-microbiome-covid19-severity-coronavirus-inflammation/
Next, some vaccine links
kindly sent along from a LIR reader in Canada. The links come from a most
informative update from Stanford Hospital in California.
World
Health Organization - Landscape of COVID-19 candidate vaccines . https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccines
NY
Times Coronavirus Vaccine Tracker . https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html
Stanford
Website . https://racetoacure.stanford.edu/clinical-trials/132
Regulatory
Focus COVID-19 vaccine tracker . https://www.raps.org/news-and-articles/news-articles/2020/3/covid-19-vaccine-tracker
Some other useful Covid links.
Johns Hopkins Coronavirus
resource centre
https://coronavirus.jhu.edu/map.html
Rt Covid-19
https://rt.live/
Covid19info.live
https://wuflu.live/
Centers for Disease Control
Coronavirus
https://www.cdc.gov/coronavirus/2019-ncov/index.html
The Spectator
Covid-19 data tracker (UK) https://data.spectator.co.uk/city/national
Technology Update.
With events happening
fast in the development of solar power and graphene, I’ve added this section.
Updates as they get reported.
'Flashing' new 2D materials Metastable metallic nanoparticles
could find use in electronics, optics Date: January 11, 2021
Source: Rice University
Summary: Scientists extend their technique to produce
graphene in a flash to tailor the properties of 2D dichalcogenides, quickly
turning them into metastable metallics for electronic and optical applications.
Rice University scientists have
extended their technique to produce graphene in a flash to tailor the
properties of other 2D materials.
The labs of chemist James Tour and
materials theorist Boris Yakobson reported in the American Chemical Society's ACS
Nano they have successfully "flashed" bulk amounts of 2D dichalcogenides,
changing them from semiconductors to metallics.
Such materials are valuable for
electronics, catalysis and as lubricants, among other applications.
The process employs flash Joule
heating -- using an electrical charge to dramatically raise the material's
temperature -- to convert semiconducting molybdenum disulfide and tungsten
disulfide. The duration of the pulse and select additives can also control the
now-metallic products' properties.
"This rapid process permits us
to make an entirely new class of highly valued materials in large scale and
without the use of solvents or water," Tour said.
Two-dimensional dichalcogenides look
like hexagonal graphene from above, but viewing them from an angle reveals a
sandwichlike structure. In molybdenum disulfide, for instance, a single plane
of molybdenum atoms sits between similar, but offset, planes of sulfur.
Making each material in its metallic
phase (known as 1T) previously required far more complex processes, according
to the researchers. Even then, the products were known to be unstable in
ambient conditions. Flash Joule heating appears to solve that problem,
producing metastable dichalcogenides in a thousandth of a second.
Powdered, commercially available
dichalcogenides mixed with carbon black or tungsten powder to increase their
conductivity were placed in a ceramic tube capped with electrodes and flashed
with more than 1,350 amps of power for a fraction of a second, then rapidly
cooled. With the tube under vacuum, extraneous gases were vented, leaving
mostly pure metallics to be harvested.
According to the Yakobson team's
calculations, the large energy input forces structural defects to appear in the
materials' crystal lattices, adding negative charges that make 1T the
thermodynamically preferred phase.
"It is an interesting
fast-forward incarnation of Le Chatelier's principle: Under voltage, the
material changes to a more conducting 1T phase, to counteract/reduce the
applied electric fields," said co-author Ksenia Bets, a researcher in the
Yakobson group. "Our detailed computations reveal that the kinetic path is
indirect: The sublimating sulfur creates a vacancy-rich lattice that
energetically prefers a 1T structure."
The fact that conditions and
additives can influence the final product should lead to a systematic study
about possible variations, Tour said.
More
https://www.sciencedaily.com/releases/2021/01/210111135848.htm?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+sciencedaily%2Fmatter_energy%2Fgraphene+%28Graphene+News+--+ScienceDaily%29
Every election is a sort of advance auction sale of stolen
goods.
H. L. Mencken
No comments:
Post a Comment