[MUSIC PLAYING]
ROCHELLE WALENSKY: [INAUDIBLE] on the Delta variant
from several states and other countries
indicate that, in rare occasions,
some vaccinated people infected with the Delta variant
after vaccination may be contagious
and spread the virus to others.
In areas with substantial and high transmission,
CDC recommends fully vaccinated people wear masks
in public indoor settings to help
prevent the spread of the Delta variant and protect others.
MONICA GANDHI: So I think that, essentially, part of the reason
they made that decision is because
in a Provincetown outbreak.
And this was about 60,000 people that descended on Provincetown
at a time that we didn't need to wear masks inside,
happened to be raining that weekend, really
high kind of stress environment for the vaccines,
lots of inside time, no masks, closed windows,
mixed population, some unvaccinated, and really
a lot of intimacy as well.
All of that put together, there was
a high rate of symptomatic breakthroughs
in that outbreak study.
About 3/4 of people had some symptoms.
But luckily, what we really need to do
is quantitate breakthrough infections
under more normal circumstances, not a high stress situation.
Just what are people doing every day?
And really what the data gathered from Virginia
and from Washington state and from Utah,
putting it all together, the real risk is about one
in 5,000.
In more high incidence regions, in
places like San Francisco, where I live,
lower event, so probably even lower in Vermont about one
in 10,000.
The question is, how much can you
spread if you're vaccinated?
And I think there's two ways to think about it,
If you have symptoms and you don't have symptoms.
So if you have symptoms and you have
like a cold or a flu or mild symptomatic breakthrough,
can you spread?
Well, the Provincetown study was just one study, one point
in time, looked like the viral load was the same in vaccinated
and unvaccinated.
But again, it didn't do serial viral loads.
There was a study from Singapore that showed us that among Delta
symptomatic breakthroughs, for one point in time,
the viral load may be the same.
But then the viral load comes down very quickly
in vaccinated individuals, as compared to unvaccinated
that it takes a while.
And that makes sense because your immune system
is going to fight that virus, bring down the viral load.
So you're likely not as transmissible.
There are some people who have had severe breakthroughs
and have needed to be hospitalized after vaccination.
The CDC actually does track this data.
And one thing a lot of people are asking the CDC to do
is please tell us all the characteristics
of those severe breakthroughs because those
are likely the people who are going to need a third shot.
Immunocompromised is definitely going to be on the list.
I think it's really important for the CDC
to give us the demographic data of those severe breakthroughs.
And I actually think our messaging for the last month
has been really not positive.
And really, what's going on is that vaccinated people are
really very protected from severe disease, really high,
over 96% in many studies, and that this risk
of these mild breakthroughs depends on how much community
transmission is in your area but is really quite low if you're
just doing your normal things.
And so one in 10,000.
And so because of that, I think we may have been giving
a message that sounds like the vaccines
aren't working very well, which, to me,
could scare the vaccinated.
And actually doesn't make the unvaccinated
think they should get a vaccine.
So I have been, yes, very upset by the messaging
and think we need to be way more positive.