Dr. Melanie Swift: A booster vaccine is intended to be a
reminder to your immune system. Right now we're in a situation
where we can see that over time, and it does take a long time six
to eight months or more immunity that people achieve from the
COVID vaccine does start to wane. The good news is that it's
waning mostly against mild infection. And we still do have
protection from those early vaccines against severe
infection. But we want to stop transmission. And we want to
keep people from getting any form of infection. So boosters
are going to be recommended for everyone. They're really
different things with different purposes, the primary
vaccination series is intended to build an initial immune
response. Think of it like painting your house, you
sometimes can get good coverage with one coat of paint,
sometimes you need to occasionally, you might need
three coats of paint to get that good coverage. So it's the same
way with vaccines, some people might have a great response to
one dose, most people need two doses of the mRNA vaccines to
get a great response. But what we've learned is that some
people actually need a third dose to get a better response to
that initial vaccine. And that's people who are immune
compromised. So their immune systems aren't working very
well. And they do need additional doses of vaccine to
respond. Over time, once you've achieved that initial response,
your immunity may still wane. And you could need a booster. So
you might need another coat of paint, you know, down the road
when the initial one starts to wear thin or get get stains on
it, you know where we're down, giving another coat of paint is
like giving a booster right now, we are giving that third dose
and planning to give that booster dose with the same
formulation of the original vaccine. But that could change
over time the manufacturers are studying variants of that
initial mRNA vaccine that can be designed to cover mutations that
some of the variants of concern are exhibiting. So it may be
that we get annual boosters, and over time each year, that might
be a different actual vaccine that helps to provide better
protection against the Coronavirus strains that are
currently circulating, much like we do with flu vaccine. You
know, we already have this concept, we get a new flu
vaccine every year, it covers different strains than previous
years. So booster just means that your immune system will
start to lose immunity over time doesn't mean that the initial
vaccine didn't work. And in fact, the immune response that
we typically see in healthy people from the mRNA vaccines
looks like it far exceeds what you really need in order to
protect you. And we don't have a perfect lab test that will show
us just how immune you are. But we do look at something called
neutralizing antibodies that do seem to correlate fairly well
with protection against infection.
response. And then over time, those antibodies start to wane.
And it takes a while before it wanes to a point that's actually
important because there's this extra, extra strong immune
response of over and above what we actually need. And so that
can wane for months and months before we become vulnerable.
Again, so far, it looks like this side effect profile from a
third dose is very similar to what was experienced with a
second dose. Not any worse, perhaps a little milder, and
that probably has to do with the time that's elapsed since you
last had that vaccine. So getting that initial series,
you're taking a vaccine three or four weeks after you just had it
and your immune system is really responding robustly, giving
people more of those side effects. But after months later
with a booster dose, it doesn't look like there's any more
robust immune symptoms that people would have. But they can
expect to have those typical vaccine side effects. So they
can have a headache, they could feel tired, they could have a
low-get
grade fever, they could have some muscle aches. And those
still happen really quickly and resolve on their own. Within two
to three days, we are seeing some waning of immunity against
the Delta variant, we still do find that the vaccines are
helping a lot to prevent severe disease and hospitalization even
this many months out. But clearly, the Delta variant has
some resistance to that vaccination, and we want to stop
it spread. So boosting people now means that we can reduce
those milder infections and those asymptomatic infections
that contribute to spread. And remember when this virus is
spreading in our community, even if it's not causing symptoms, it
has the chance to mutate. And those mutations can randomly
lead to the development of a new variant. And that variant might
be even worse than the Delta variant. So we need to do
everything we can now to stop it. The interesting thing about
the Johnson and Johnson vaccine is two things. One is that the
company is actually studying a second dose in that Prime
series. And a study called Ensembl to and they're looking
at spacing, a second dose from that first dose two months
apart. And we don't have the results of that study yet. And
the FDA hasn't given authorization for a second dose
in the J&J series, nor has there been any recommendation to do
that. So we're waiting for the results, the full results to be
known of that study. The second thing that's interesting about
the J&J vaccine is that there are some data that show over the
first six months, some markers of immunity that we follow in
the research study bloodwork shows some improvement in
immunity over time. Now, we don't know if that's going to
translate into, you know, continuing to prevent infection
at eight months, 10 months down the road. But it is a signal
that there's something about that add no virus vector that
may make its actions more prolonged on the immune system
than the mRNA vaccines.