If you've been fully vaccinated, can you still get COVID-19?
We're going to talk about breakthrough infections
with Dr. Katherine O'Brien today.
Hello and welcome to Science in 5,
I'm Vismita Gupta-Smith.
Welcome, Kate.
My first question to you is,
please explain breakthrough infections.
How come people can still get COVID-19
even when they're fully vaccinated?
The vaccines that we have against COVID
are incredibly effective vaccines.
And people have seen the results from the clinical trials
of, you know, anywhere in the 80 percent range,
90 percent range of efficacy.
But that doesn't mean that 100 percent of people,
100 percent of the time are going to be protected against disease.
There is no vaccine that provides
that level of protection for any disease.
So we do expect in any vaccine program that there will be
rare, but there will be cases of disease
among people who were fully vaccinated
and certainly among some people who were partially vaccinated.
This doesn't mean that the vaccines aren't working.
It doesn't mean that there's something wrong with the vaccines.
What it does mean is that not everybody
who receives vaccines has 100 percent protection.
What we do want to really emphasize for people
is that it's so important to get vaccinated
because these vaccines are really effective
and it gives you a really good chance
of not developing disease.
Kate, how frequent are breakthrough infections?
And if you are fully vaccinated
but happened to catch COVID-19,
what does that look like?
So we're learning a couple of things
about breakthrough infections, Vismita.
The first is that the degree of severity of disease
among people who have a breakthrough infection
is less severe than the severity of disease
among people who aren't vaccinated.
So vaccines are operating in a couple of different ways.
First, of course, they're preventing
people from getting disease at all.
And even when disease does occur among a person,
people who are fully vaccinated,
the severity of that disease is less.
The second question is about how how often
we're actually seeing breakthrough infections.
We're monitoring this really carefully.
And there's a couple of things I want to say
about breakthrough infections.
The first is that they are uncommon.
And so this is not something that's happening
in an unexpected way, but they don't happen equally
among all different kinds of people.
People who are at increased risk of disease,
so people with frail immune systems,
people who are in older age groups,
they have a greater risk of having
breakthrough disease than other people.
So it's not an equal risk of breakthrough disease.
The second point here is that we're seeing
more cases of breakthrough disease,
in part because people are stopping the other interventions
that reduce the transmission of this virus.
So when the virus starts to transmit at a greater and greater pace
and with greater frequency, there's a lot more exposure
that everybody has, including people who are vaccinated.
So Kate, people may be wondering
if they can still catch COVID-19
even after being fully vaccinated
and if they can still infect others,
then why vaccinate?
So this is a question that lots of people are asking.
And I really want to emphasize
that vaccines do a number of different things
to protect you and to protect others.
So we've already talked about how the main function of vaccines
is to protect you against getting disease.
We've also talked about the fact that if you were to get disease,
a rare event among vaccinated people, but it does occur
that your disease will be less severe
than it would have been if you weren't vaccinated.
And the third thing that vaccines do
is they reduce the transmission of the infection of the virus
from one person to the next.
And the way that vaccines do that is in a number of different ways.
The first is they can protect you against getting infected at all.
The second way that they work is if you become infected,
you're actually shedding that virus for a shorter period of time
than if you weren't vaccinated.
And the third way that vaccines work is, again,
if you happen to get infected, the amount of virus that you have
in your nose, in the back of your throat that you are shedding
and potentially transmitting to somebody
is less of the virus.
There's less density of the virus in you
and so less risk that you transmit it to somebody else.
And what is so critical is
interrupting transmission of this virus
has to be "vaccines and"
it has to be vaccines and all the other things that we're doing,
especially while people are still in the process of getting vaccinated.
So now really isn't the time for us to reduce
those other interventions while we're living in communities
that don't have substantial vaccination yet.
Thank you, Kate.
That was Science in 5, today.
Until next time, then.
Stay safe,
stay healthy and stick with science.