Vaccinated individuals are getting infected with the Delta variant, CDC data shows

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The outbreak of coronavirus infections, including COVID-19 vaccine breakthrough infections, is associated with large public gatherings, including one in Barnstable County, Massachusetts, according to the Centers for Disease Control and Prevention in its weekly Morbidity and Mortality report.

Following multiple public events in that county, 469 COVID-19 cases were identified among Massachusetts residents who traveled to the Provincetown area July 3-17. Seventy-four percent occurred in fully vaccinated people, the CDC said, with testing identifying the Delta variant in 90%.

WHY THIS MATTERS

The information shows that the Delta variant is highly transmissible, even among vaccinated individuals.

CDC Director Rochelle Walensky followed up the weekly report with this statement: "High viral loads suggest an increased risk of transmission and raised concern that, unlike with other variants, vaccinated people infected with Delta can transmit the virus.

"This finding is concerning and was a pivotal discovery leading to CDC's updated mask recommendation. The masking recommendation was updated to ensure the vaccinated public would not unknowingly transmit virus to others, including their unvaccinated or immunocompromised loved ones."

On Tuesday, the CDC updated its mask-wearing guidance to recommend that even fully vaccinated individuals put their masks back on indoors.

THE LARGER TREND

On Thursday, The Washington Post reported that the virus was being as easily spread as chicken pox, based on internal documents released by the CDC.

The CDC was criticized for changing its mask guidance without releasing the data on which it was based, the report said. Today's weekly report contains that data.

The Post today reported on the Massachusetts outbreak, saying few of the infected vaccinated individuals required hospitalization.

Twitter: @SusanJMorse
Email the writer: susan.morse@himssmedia.com