CNN’s chief medical correspondent Sanjay Gupta broke down the US Centers for Disease Control and Prevention’s new study about the Delta Covid-19 variant spread— and what its findings could mean for vaccinated and unvaccinated Americans across the country.
“The idea that people who were vaccinated still were far less likely to develop severe symptoms, hospitalizations, deaths, all the things that we’ve talked about since the vaccines were first authorized, remain true. The vaccines work, in that regard, but the idea that someone [who is vaccinated] could test positive and still develop enough virus in their nose and mouth to transmit is really what this data is showing,” Gupta told CNN’s Ana Cabrera following the release of the study.
The study, published by CDC Friday, describes 469 Massachusetts residents who were infected in a July outbreak in Barnstable County, which includes the summer vacation destination Provincetown. No deaths were reported among them.
About 74% — or 346 cases —had been fully vaccinated. Of those cases, 79% reported symptoms. Genetically sequenced cases revealed the Delta variant as the main culprit.
“I still want to reiterate just how effective the vaccines can be at doing the things that people I think looked for them to do the most. Prevent severe hospitalization and death. But it is clear that this Delta variant is far more transmissible and as a result of that, probably even vaccinated people are transmitting this at a higher rate than we thought,” Gupta said.
In terms of what comes next, Gupta said this study will likely spark new questions about preventative measures, including masking and when Americans may need a booster shot.
“They’re saying this is really, really contagious. So even if there’s not a lot of viral transmission now, it’s likely to increase, because of the contagiousness of this and also because we’re going into cooler and dryer weather where we know virus tend to transmit more easily anyway,” Gupta said. “So, I think there’s going to be some changes that come about here, with regard to those recommendations, both on boosters and masking, you know, throughout the country.”
On Tuesday, Walensky previewed these findings while unveiling guidance that people in areas with “high” or “substantial” Covid-19 transmission should resume wearing masks indoors. Over 75% of the US population live in these areas.
Here’s a look at some of the key findings of the study:
Read more about the CDC study here.
CNN’s Michael Nedelman contributed reporting to this post.