So, how long will the protective effect last?
Well, that's not known, in fact
there are many questions that emerge,
as we go further into the pandemic
and here are some of the ones to
which we don't yet have answers.
It appears, that vaccine
recipients in the vaccine trials,
have had protective immune response,
for a minimum of one year after vaccine,
but that number will continue to lengthen
as we go further into the pandemic.
Can the vaccines prevent asymptomatic infection
or can they prevent transmission?
The tentative answer so far is, yes,
but how successfully remains to be determined.
Will they prevent infection by all
the current or emergent strains?
To date, the answer is, yes,
but would decrease efficacy
compared to the original strain.
Will they be effective in
Here the data would suggest
that immunocompromised patients
are not all created equal,
those who are on immunomodulatory
drugs for example,
somebody with systemic lupus or
erythematosus or rheumatoid arthritis
on a biologic agent, still have a robust response,
while a solid organ transplant recipient
or a chemotherapy recipient does not,
so, it's a variable response and there may
be a need for booster in those patients.
Will the vaccines be effective in patients,
who are at high risk for severe
COVID-19 as those who are at low risk?
Again, the answer would suggest, yes,
but this is a smaller more
difficult to study population,
because of complications from
those same comorbidities, which,
already lend to morbidity and mortality.
So, what are the major concerns
with vaccine strategies?
Perhaps, the hugest one is
getting vaccines delivered,
to as many people in the world as is possible
and of course, there are many countries
that are horribly under-resourced
and either have no vaccine doses whatsoever
or have been able to immunize less
than 1% of that country's population.
So, making vaccines available to all countries,
all people in the world, as soon
as possible is a critical concern,
if we have and wish to have any chance
of getting through this pandemic.
Protecting those who are at
highest risk for severe disease
or those for whom the risk
of infection is significant.
So, protecting healthcare workers,
so, that we can continue to care
for those who do have COVID-19.
Protecting the elderly,
the ones who are at highest risk
of hospitalization and death
and including those who have immunodeficiency
and then represent a huge burden
in healthcare infrastructure.
What about the variance?
So, following the impact of the
mutant variants of the virus
and adapting our vaccine
strategies to reflect those,
all these are our major concerns and
especially the duration of immunity.
How do we detect if the vaccines
are successful and for how long?
Is it simply checking antibodies?
or should we look at T-cell function,
should we look at plasma cell
derivations populations and lineages
of COVID-19 effective plasma cells
or neutralizing antibodies,
versus other antibodies.
So, there are a whole bunch of concerns
which remain to be fleshed out.
And then finally, limiting the insertion
of the actual SARS-Coronavirus II,
into the viral milieu of
humans in an endemic matter.
What does this mean?
At some point in time, way, way, way,
back when influenza was also a pandemic,
however, it was so successful,
that it entered human infectious milieu
and now creates an annual epidemic.
The fears are that our point of no return for,
SARS-Coronavirus II has already been crossed
and that we will likely have seasonal recurrences,
just like we do with influenza,
which, will require an annual booster vaccine.
That is absolutely, I think a likely reality,
if not already a true reality.
And then what are the long-term
complications of the disease?
For example, those individuals
who are long COVID-19 survivors,
the long haulers as they've been called,
which has horrible and tremendous
impact on quality of life,
can those be prevented by COVID-19 vaccination
and can those be addressed as we
bring this pandemic under control?
So, lots yet to be determined,
the science of course is evolving
at a rapid pace in this pandemic
and that is a good thing,
because otherwise nature in
its abhorrence of a vacuum,
will continue to win,
in creating variance,
which, will eventually be the death of us.