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 Vaccine-associated myocarditis tends to resolve quickly
Cases of an inflammation of the heart muscle known as myocarditis
have been reported after receiving COVID-19 shots, mostly in young
men after the second dose of the mRNA vaccines. When myocarditis
symptoms, such as chest pain and rapid or irregular heartbeats, do
occur after vaccination, they usually resolve quickly, suggests a
report of a small study published in the journal Circulation.
Doctors tracked seven male patients, ages 19 to 39, who were
hospitalized for myocarditis-like illness not long after receiving a
COVID-19 vaccine manufactured by either Pfizer and BioNTech, Moderna
- the two mRNA vaccines - or Johnson & Johnson. All recovered and
left the hospital after two to four days of treatment. Study
co-author Dr. Christopher deFilippi of the Inova Heart and Vascular
Institute in Fairfax, Virginia, noted that in his health system,
which represents about 2 million patients, myocarditis after
COVID-19 vaccination has been a "rare event" and "fortunately so far
associated with a benign outcome." The U.S. Centers for Disease
Control and Prevention this week said reports of the heart condition
occurred at a rate of 12.6 cases per million people who received
either the Pfizer/BioNTech or Moderna vaccines, a higher rate than
would be expected in the general population. However, deFilippi's
team advised that given the dangers of COVID-19, even for younger
adults, "the risk-benefit decision for vaccination remains highly
favorable." (https://bit.ly/35NyLRv)
Delta variant's spike fuses cells to infect them
Compared to the spike protein on earlier versions of the coronavirus,
the spike on the worrisome Delta variant is better able to break
into lung cells and fuse them together, researchers have discovered.
[to top of second column] |
 "Spread by cell-to-cell fusion
allows the virus to spread faster in infected
people and partially hide from the immune
system," said Markus Hoffman of
Georg-August-University Göttingen in Germany,
coauthor of a report posted on Wednesday on
bioRxiv ahead of peer review. "For example, if a
cell that is infected by the Delta variant is
forced (by the spike protein) to fuse with a
neighboring cell that is not yet infected, this
allows the virus to enter the new cell much
faster" than if the virus particles first needed
to be released from a previously infected cell,
he explained. By spreading via cell-to-cell
fusion, the virus reduces its risk of
encountering immune system cells that might
attack and inactivate it, Hoffman added. These
"skills" might make the Delta variant - first
identified in India and now circulating widely
in many countries - more transmissible, and the
resulting illness more severe, the researchers
said. The researchers also found that although
the Delta variant can evade antibodies, it is
not completely resistant. "It might be possible
that the Delta variant can infect people who are
vaccinated (especially if only one of two
vaccine shots have been administered so far),
but vaccination is highly effective in
preventing severe disease," Hoffman said.
(https://bit.ly/3A2bGIH)
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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