South Korean health officials said recovered coronavirus patients who later tested positive again only did so because “dead” virus particles remained in their bodies — not because they became reinfected.
A total of 292 people in the country who were cleared of the deadly
bug later tested positive for COVID-19 again — a phenomenon that
initially puzzled officials, the Korea Centers for Disease Control and
Prevention said, according to a report in Newsweek.
But they’ve now determined that residual fragments of the virus are likely responsible.
“RNA fragments still can exist in a cell even if the virus is
inactivated,” said Oh Myoung-don, who heads the KCDC’s clinical
committee for emerging disease control, Newsweek said.
“It is more likely that those who tested positive again picked up virus RNA that has already been inactivated.”
Still, there are some concerns about South Korea’s positive retests
as the number of second-time diagnoses has steadily risen. Two weeks
ago, repeat diagnoses accounted for about 2 percent of the country’s
recovered patients. By Wednesday, the number had risen to 2.7 percent,
and 3.4 percent among children. Preliminary tests released by the KCDC
on April 17 determined that those patients re-tested positive an
average of 13.5 days after being cleared and discharged from isolation —
although the time spanned as long as 35 days, the report said.
Scientists studied 137 of the initial cases and reported that 61 of
the patients showed mild symptoms, 72 were asymptomatic and four others
were still being studied.
However, health officials said there was no indication yet that those patients had spread the virus to others.
“Contact tracing on these re-positive cases is also underway to
identify the possibility of secondary infection,” the center said in an
April 26 report. “No new case has yet been confirmed that resulted from
exposure to the re-positive cases. The contracts are still under
monitoring.”
As of Thursday morning, South Korea had 10,765 reported cases of
COVID-19, with 247 deaths, according to Johns Hopkins University, which
is tracking the global pandemic. https://nypost.com/2020/04/30/dead-coronavirus-particles-may-cause-positive-test-results/
A group of pandemic modeling experts from the University of Sydney’s
Faculty of Engineering have published new research that simulated viral
influenza outbreaks to examine the efficacy of pandemic interventions in
the absence of a tailored vaccine.
The general use of low-efficacy vaccines, coupled with a targeted
application of antiviral medications, may be effective at countering the
spread of influenza pandemics, new research from the University of
Sydney has found.
Published by the Journal of The Royal Society Interface, the modeling sought to examine the effectiveness of pandemic interventions in the absence of a strain-specific vaccine.
“Pandemics typically occur with the emergence of new viral strains
for which no tailored vaccine exists,” said Dr. Cameron Zachreson from
the University’s Centre for Complex Systems, who in 2018 published
research that found urbanization and air travel were leading to a
growing risk of pandemic in Australian cities.
“Without a readily available vaccine, governments must mitigate
outbreaks in other ways, making do with mechanisms at hand, such as
antiviral medications, social distancing and low-efficacy vaccines
developed for different viral strains. These are known as pre-pandemic
vaccines.”
Dr. Zachreson’s team found pre-pandemic vaccines are most effective
at containing a pandemic when combined with fast, contact-targeted,
antiviral medication, which helps reduce transmission.
“These targeted interventions need to be implemented quickly compared
to the transmission rate of the disease,” said Dr. Zachreson.
“The more effective a targeted strategy is at mitigating the
epidemic, the longer it will have to be in place,” he added. “Mitigation
will slow down disease spread but is unlikely to eradicate the pathogen
completely.”
Even if a pre-pandemic vaccine is unable to bring about herd
immunity, it can slow the spread of the virus and open a longer time
window in which other measures can be effectively implemented, the
researchers found. Lessons for the COVID-19 pandemic
“Our study focuses on influenza,
for which many vaccines have previously been developed. There are no
coronavirus vaccines available so pre-pandemic vaccination is not
currently possible for COVID-19,” said Dr. Zachreson.
“If, hypothetically, a low-efficacy coronavirus vaccine was
developed, our study would support its distribution in combination with
other measures, as this would likely make them more effective.
“Another takeaway is that timing is everything in preventing a pandemic
with targeted interventions. Cases must be identified, contacts traced,
and measures implemented before the disease has time to spread within
the community.” Targeting neighborhoods less effective than contact targeting
The study showed that giving antiviral medication to people living in
the same neighborhoods as index cases (the first documented patients
within a population) was inefficient and did not significantly impact
the disease’s rate of spread.
“On the other hand, giving antiviral medication to the social
contacts of index cases did slow down disease spread if the response was
fast compared to disease transmission speed,” Dr. Zachreson said.
“While there are no known antivirals that are effective for COVID-19,
our study does reinforce the importance of contact tracing for the
targeting of mitigation measures, as opposed to targeting by residential
location.” How the modeling worked
The AceMod simulator, a peer-reviewed method created by the Centre
for Complex Systems, comprises over twenty-four million software agents,
each with attributes of an anonymous individual, such as age,
occupation, susceptibility and immunity to diseases. Contact rates
within different social contexts, such as households, household
clusters, local neighborhoods, schools, classrooms and workplaces are
also built into the program.
The set of generated agents captures average characteristics of the
real population and is calibrated to 2016 Australian Census data with
respect to key demographic statistics.
More information: Cameron Zachreson et al. Interfering with influenza: nonlinear coupling of reactive and static mitigation strategies, Journal of The Royal Society Interface (2020). DOI: 10.1098/rsif.2019.0728
Nano cap ThermoGenesis (THMO+73.6%)
jumps more than a 13x surge in volume in apparent response to
performance characteristics of its SARS-CoV-2 IgM/IgG Antibody Fast
Detection Kit that it published on its website.
Although the sample sizes were modest, the data showed 100% sensitivity (n=10) and 95.8% [should be 96% (n=48/50)] specificity.
The latter is the most important characteristic
for epidemiologists since too many false positive results will
compromise their efforts in contact tracing and research into the spread
and persistence of the pandemic.
Although Inovio Pharmaceuticals IncINO 10.04%
reported positive interim results from Phase 1 and 2a of its MERS
vaccine, the valuation of the stock already reflects this, especially
given the increase in share count since the end of 2019, according to
Roth Capital Partners.
The Inovio Analyst
Jonathan Aschoff downgraded Inovio stock from Buy to Neutral and maintained a $13 price target.
The Inovio Thesis
Inovio Pharmaceuticals’ share count will rise by over 10 million
shares with its at-the-market capital offering of $150 million, Aschoff
said in the Thursday downgrade note. (See his track record here.)
The company has announced solid interim results for its MERS vaccine
INO-4700 and is scheduled to present details at the ASGCT conference in
mid-May, the analyst said. Yet there are several drug makers, many of
which are much larger than Inovio and have global commercial operations,
that are working aggressively on COVID-19 therapies, he said.
It may take more than just positive clinical data to “come out among
the group that materially benefits from treating the world against this
virus,” Aschoff said. https://www.benzinga.com/analyst-ratings/analyst-color/20/04/15923041/roth-downgrades-inovio-on-valuation-despite-positive-mers-vaccine-data
