hey guys i'm dr mike hansen and welcome to another video recently the delta variant of covid 19 aka
b16172 has been spreading across the globe is it more contagious will the vaccines work against it
is it a deadlier disease with worse symptoms i'm going to get to these questions in a little bit
but first a quick update on covid the us has over 33 million confirmed cases and more than
601 000 deaths worldwide that's about 180 million cases and close to 4 million deaths
according to the cdc almost 150 million americans
have been fully vaccinated that's about 45 percent of the population the delta variant
first emerged in india and then it made its way to england to become the dominant strain there
is the delta variant more pathogenic meaning is it more likely to cause worse disease
yes in a study done in scotland which was published in the lancet researchers showed
that the risk of being hospitalized with the delta variant is double that of the alpha variant
recently the delta variant has made its way to the u.s where already constitutes 10 percent of
covid cases however that figure is doubling every two weeks and it's only a matter of time
before it becomes a dominant strain right now in the midwest it makes up about 25 percent of cases
in colorado montana north and south dakota utah and wyoming now in a study done in the uk
from may 20th to june 7th the researchers led by stephen riley they looked at their
data which suggested that the delta variant is about 60 more transmissible than the alpha
which was the variant that was first identified in the uk which was more contagious than the original
strain that was originally emerging from wuhan the research team showed that with the delta
variant there was a doubling time of 11 days in an estimated r or reproductive number of 1.44
and those younger than age 50 were two and a half times more likely to be infected compared
to older people another study looked at whether vaccines monoclonal antibodies or antibodies
derived from covid 19 survivors could neutralize the delta variants here are some of the takeaways
from that study for one the data showed that the delta's variant affinity for the ace2 receptor
was slightly better compared with the original wuhan strain one of the delta's mutations is
in its receptor binding domain and that's what allows for this this virus uses spike protein to
bind to the ace2 receptor in the body it's the key in the lock analogy the virus then fuses
with the cell membrane this process relies on cleavage meaning enzymes on the cell membranes
that cut that spike protein at two different sites which triggers the cell to then engulf this virus
it's the turning of the deadbolt if you will well guess what the delta variant is also better at
doing there's a second delta mutation at one of the cleavage sites better cleavage better
reproduction another takeaway from the study is that the authors concluded that neutralization
of both viruses is reduced when compared with the original wuhan strain but there's
no evidence of widespread antibody escape they said the data did suggest that those previously
infected with covid may be more susceptible to re-infection by the new delta variant
also it looks like monoclonal antibody treatments are ineffective at treating the delta variant
the big concern is vaccine escape meaning that the current vaccines will become far less effective
as the virus evolves so far it hasn't happened but eventually we'll need new vaccines for the
variants likely a yearly thing the good news is that these vaccines are still protective against
the delta variant according to research released by public health england for the pfizer vaccine
after both doses it was 88 effective in preventing symptomatic disease and 96 effective at preventing
hospitalization for the oxford astrazeneca vaccine if they had both shots it was 92
effective at preventing hospitalization if you only get one shot of either one of these vaccines
the effectiveness is pretty low it's around 30 to 40 percent so more studies will soon
be available when it comes to the moderna and the johnson and johnson vaccines there's also
talk about this delta variant having new symptoms and possibly more severe symptoms so tim spector
who's a professor of genetic epidemiology at king's college in london he runs the zoe covet
symptoms study this is an ongoing uk-based study where people can enter their symptoms on an app
which then gets analyzed by the researchers from this study he noted that covid is now acting
differently it's more like a bad cold especially in the younger population the number one symptom
being headache and then other symptoms including sore throat runny nose and fever so that's gonna
be all for this one thank you for watching and if you did like this video don't forget that
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