Booster shots.
Do we need them or not?
The U.S. has already made clear its position
boosters already encouraged for those with compromised immune systems.
It's a true statement that we believe sooner or later
you will need a booster for durability of protection.
[Chang] They've administered nearly a million boosters to date
and they want to make them available to all Americans starting Sept. 20.
Israel is doing much the same
offering most citizens a booster starting five months after their second dose.
So with the highly transmissible delta variant threatening
a dangerous fourth wave here in Canada
what should we expect about whether boosters
are in our near future?
Well here to answer that question
Infectious Diseases Specialist Dr. Zain Chagla.
Hello doctor, so the question: are they necessary or not?
Yeah I mean I think they're coming in our future at some point
and you want to look to places like the United States and Israel
in terms of what's the same about their vaccine campaign
and what's different.
Well, we know we largely did use mRNA vaccines
so that really does say, you know, there is a waning effect
and we've seen that even in the long-term data from Pfizer and Moderna
but you also see that effect really in people
that got the dose on time
so that three to four weeks after their first dose
and, you know, largely the people that were vaccinated first.
So Israel showed that people that were vaccinated in January, in February
had a little bit higher risk of breakthrough infections
as compared to people who were vaccinated more recently.
Right, let me jump in though because when you talk about waning immunity
how urgent is that problem
like how much is protection actually waning over the course of several months?
Yeah and this is where it gets really murky, right?
We are seeing breakthrough infections amongst individuals
that have gone to that January, February mark from vaccines
but we haven't necessarily seen a significant rise in severe disease
people who require hospitalization, people who need the ICU
and people who die from COVID-19
who have gotten vaccinated in that January, February piece
and so this is where the the fields are a bit murky.
The United States' suggestion is while there may be a waning
of that initial immunity, the one that protects you from just getting infected
it's only a matter of time before you have loss of protection against that severe immunity
but a lot of immunologists and infectious disease physicians
will say, you know, it's not clear yet
when that part is gonna wane and really what the solution is.
Do we vaccinate now, do we vaccinate in a few months
do we wait for a newer vaccine series to come out
or again do you just give it to vulnerable individuals who are at higher risk
and let the general population wait a little bit more
until you get better data?
But if we primarily have safety in mind
I guess my question is, you know, why wouldn't we follow the example
of a place like the United States or Israel
and kind of err on the side of caution, right?
Wouldn't the prudent thing be to get boosters
into as many arms as possible so you avoid any problems down the road?
Yeah and I think, you know again
prioritizing groups like those who are elderly
who have the most risk of having a dysfunctional immune response
those who have major immunocompromising conditions
similarly who have the highest risk of having a blunted immune response
it makes sense and we are starting to roll this across Canada.
That general population piece though
you know, the investment of millions and millions of vaccines in Canada
the United States and Europe into groups where we're not sure
if they're even at significant risk of severe disease
after a full vaccine series
even being low risk to begin with if they're younger
it starts bringing up questions especially when we haven't vaccinated
a significant amount in the world and again there is a vaccine shortage
for many countries where this is going to be felt even more when
richer countries take millions of doses back
to vaccinate the population.
Okay so then here's the crystal ball question to finish off.
When should the Canadian general public expect to have boosters
recommended to them and for that matter
how often would they have boosters recommended to them?
Yeah, so I mean I think somewhere at about the year mark
most people may be offered their third vaccine
and the question is again what vaccine?
Pfizer and Moderna are developing variant-specific boosters
and perhaps that may be the solution for us as compared to
re-vaccinating ourselves with the same vaccine.
The timeline you know is really dependent and the long-term responses
really depend on what happens.
We're obviously in a new world here
but, you know, I think we will likely see more and more data come out
from places like Israel
from places like the United States to really say what this means
from a logistical standpoint
from a sensitivity standpoint and again how to really balance this on the
cost-benefit of the world and when to do this appropriately.
All right Dr. Chagla, very interesting chat thank you so much for your time.
No problem.