Vaccines in general, are the best tool for
prevention against any infectious disease.
And for them to be effective and to be accepted,
as being effective and
again this is any infection,
it should be at least 50% effective.
Specific to COVID-19 and the
SARS-Coronavirus II vaccines,
the initial requirements in the United States,
were that the new vaccine products,
be at least 50 % effective.
Now, as we are moving forward into the current,
there are many vaccine products,
The CDC recommends everyone aged six
months and older get vaccinated for COVID.
So, vaccines are always the best
tool for prevention as noted
and luckily, the COVID-19 pandemic,
has triggered creation of
very successful vaccines,
even when compared to the influenza vaccine,
which is perhaps one of the most common
and upheld successful interventions.
The influenza vaccine, typically 40%
to 60% effective in any epidemic year,
but, it is still quite useful
in preventing severe disease
and preventing an overburdening
of the healthcare system.
Full vaccines then, are recommended for everybody,
including those who have had prior COVID-19,
since it has been demonstrated
that patients with mild
to even moderate COVID-19, have
a risk of second infections
or even third infections and
vaccines provide a robust,
high level of antibody protection
against currently the spike protein,
which is, quite protective even for
those who have had prior infection.
What are the types of vaccine methodologies?
And we start with the products by
AstraZeneca and Johnson and Johnson,
similarly, Russiaâ€™s products Sputnik V,
follows this methodology as well,
these are vaccines which include a
non-replicating adenovirus as the vector
or the carrier for a gene encoding the
spike protein of SARS-Coronavirus II.
The next category are the vaccines
made by Pfizer and Moderna.
These are messenger RNA vaccines in which,
the messenger RNA, specifically
and only for the S-protein gene,
are included in a nanoparticle
encapsulated lipid particle construct,
which then, triggers immune reaction.
And then a vaccine produced by Novavax,
takes the actual spike
protein itself the S1-protein,
coats it with synthetic nanoparticles
and then provides it in an
immune boosting adjuvant,
which triggers immune reaction.
So, in general, how do vaccines work?
Well, we know that vaccines work by triggering,
a specific adaptive immune response,
by the human immune system,
which then, creates memory,
so, that the individual's immune system,
can react to subsequent challenge,
by that same antigenic challenge.
Looking specifically at the
messenger RNA based vaccines
and this this is newer technology to most of us,
it is really quite unique and
exciting as a platform for vaccines,
because this process will work for
other infectious diseases as well.
In a messenger RNA based vaccine
against SARS-Coronavirus II,
the messenger RNA code for the
spike protein the S1-protein gene,
is introduced into the human body,
where, it is taken up or absorbed
by antigen presenting cells,
as with any other antigen delivery via vaccine.
However, those antigen presenting cells,
as they ingest the messenger RNA,
then go through translation
and transcription processes,
to create the spike protein and
then express the spike protein,
at their cell surface along
with MAC classes 1 and 2
and or, release the spike protein
where it is then able to be ingested
and to trigger an immune response,
by other antigen presenting cells.
So, here, we see the delivery vehicle,
the messenger RNA vaccine,
with the messenger RNA code,
for the spike protein in its little nanoparticles,
it then is taken up as the full
construct by the anti-presenting cell,
the messenger RNA is introduced
into the anti-presenting cell,
where, it is translated into spike protein,
the spike protein then is
expressed at the cell surface,
with MHC class 1 and 2 to
T-lymphocytes and B-lymphocytes,
which, are the next stage
and or secreted externally
to where it is then taken up by other
antidepressant cells in the same process
and that then drives the adaptive
immune response using T-lymphocytes
the CD4+ T-helper T-lymphocytes
and B-lymphocytes to create
So, that is the strategy, does it work?
Now, this this is a historic slide,
but it shows in the United States,
the surge or peak,
which occurred in the winter
of 2021, in the States
and you can see on the slider front of you,
around, I guess it was December, is when,w
max vaccinations started in the United States
and it took quite some time of course,
to get to anything resembling
a decent vaccine coverage
as that vaccine coverage has rolled out,
one can see a decrease in the
number of cases quite robustly,
as we go into spring of 2021.