- Mutations are universal in viruses.
When viruses enter the host cells
and replicate and make copies of their genomes,
they inevitably introduce some errors in the code.
The viral mutation is akin
to a faulty spell check mechanism
and this virus has a pretty good spellchecker
but not a perfect one.
- Like a game of telephone,
you're sending a message on to your friends
and eventually they get 10 down the line,
the message is very different from before.
This is the same with mutations,
as a mutation in a virus is introduced from replication.
Now that becomes the new starting point for replications.
Evolution is a way to continue it.
We actually called this a molecular clock.
So each point in time with what we think of as clockwork,
you have new more and more mutations that get added to that
and on average,
SARS-CoV-2 acquires one to two mutations per month.
- Many of these errors are harmful to the virus
and viruses carrying such mutations will be eliminated.
- However, some of these mutations actually
are beneficial to the virus.
They become the building blocks of selection.
- [Dr. Iwasaki] So these better fit versions
of the virus bind to the host cells
and replicate and spread better than the original virus.
- [Dr. Grubaugh] We wanna know what mutations are occurring
in specific viruses because as now this pandemic
has gone on for over a year
and it's caused millions of infections,
and there have been so many different opportunities
for selection happens,
it collectively changed the behavior of the virus,
and they called those variants.
- [Dr. Iwasaki] Why are we seeing rapid emergence
of the variants around the world?
We don't know exactly what the answer is.
But one of the possibilities is that the variants
acquired a better ability to enter the host cells
and replicate to higher titer
than the original strain of the SARS-CoV-2.
When that happens, of course,
an individual person infected
with the variant is able to replicate more virus
and transmit to a larger number of people.
- So what we want to do
with the genomic surveillance program is recognize
these variants that could be of concern
when they're at low frequency in the population,
not when everybody's infected with it.
Because when they're at low frequency in the population,
that allows us to react.
- In order to protect yourselves from these variants,
you will still need to keep wearing masks
and avoiding indoor crowding conditions,
as well as washing hands
and really getting the vaccine as soon as possible
to prevent the spread of these variants.
The mutations that concerns scientists right now
are the ones that are occurring
within the spike domain of the viral genome
because most vaccines use spike as the antigen
to immunize a person to develop neutralizing antibodies
and T-cell immunity.
- What we do know is that there are certain mutations
in some of these variants that seem
to decrease the effectiveness
of really important antibodies.
- There is a possibility that the current vaccines
may not be as effective in combating these new variants.
- Luckily with vaccines,
you don't just create one antibody or two or three.
You create many different antibodies
that recognize all different parts of the virus.
- [Dr. Iwasaki] The mRNA vaccine strategy is very flexible
and can accommodate new mutations or any kind
of sequence that are coming up in the population.
- So we have all the tools needed to stop the transmission
and the spread of these new variants.
We know what works.
If we individually and as a community,
you know, from like public health leaders on down,
really put a lot of effort into all doing our part,
these variants won't be able to take a foothold
in our community at all.