標題: South Africa coronavirus variant: What is the risk? [打印本頁] 作者: geemong 時間: 2021-4-16 13:43 標題: South Africa coronavirus variant: What is the risk?
South Africa coronavirus variant: What is the risk?
The "largest surge testing operation to SLOT date" is beginning in south London to
hunt for any new cases of Covid caused by the South African variant.
Some 44 cases have already been confirmed in Wandsworth and Lambeth, along
with 30 probable ones.
Experts say that this variant of concern - along with a few others - may be able to
get round some of the protection offered by vaccines or previous Covid infection,
although existing jabs should still work to stop severe illness.
A real-world data study in Israel - not yet peer-reviewed - found some people who
had been fully vaccinated against Covid still caught the South Africa variant.
What is the South Africa variant?
All viruses, including the one that causes Covid-19, constantly mutate into new
versions or variants.
These tiny genetic changes happen as the virus makes new copies of itself to
spread and thrive.
Most are inconsequential, and a few can even be harmful to the virus's survival,
but some variants can make the virus more infectious or threatening to the host -
humans.
The South African variant, also known as 501.V2 or B.1.351, has some significant
changes that experts are studying.
Is it more dangerous?
Some of the changes involve the virus's spike protein - the part that gains the virus
entry into human cells. It is also the bit that vaccines are designed around, which
is why experts are concerned about these particular mutations.
The South African variant carries a mutation, called N501Y, that appears to make
it more contagious or easy to spread.
Another mutation, called E484K, could help the virus dodge a person's immune
system and may affect how well coronavirus vaccines work.
There is no evidence that the South Africa variant causes more serious illness for
the vast majority of people who become infected.
Do vaccines work against the South Africa variant?
Current vaccines are designed around original Covid, but should still offer some
protection against new variants.
It is too soon to know exactly how much protection they give, until more tests are
completed, although it is extremely unlikely the mutations would render vaccines
useless.
Trials of Novavax, Janssen and the Oxford/AstraZeneca vaccines in South Africa,
where B.1.351 is circulating, suggest the variant can escape some immunity and
may not stop infections.
But experts say vaccines should still offer protection against severe and
life-threatening Covid-19 illness.作者: xiaocong7915 時間: 2021-4-29 09:11
