Delta Strain Spread in Vaccinated People on Cape Cod, CDC Says

Jul 30, 2021

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(Bloomberg) -- The delta strain spread widely in a series of densely packed summer events and large public gatherings in Cape Cod’s Barnstable County in early July, raising further concerns about the highly transmissible variant.

The findings show just how difficult the strain will be to control as Americans return to normal activities including parties and big gatherings. In July, 469 cases of Covid, primarily caused by delta, were recorded during the Barnstable outbreak and 74% of the cases occurred in fully vaccinated individuals, the Centers for Disease Control and Prevention said Friday in a study.

The findings contributed to the CDC’s recommendation that fully vaccinated people return to wearing masks indoors in areas of substantial and high transmission. Infections are soaring across the U.S., and the federal government and some localities are mandating masks and in some cases vaccines.

Almost four out of five vaccinated patients with breakthrough infections were symptomatic and four vaccinated patients were hospitalized. The findings were published in CDC’s Morbidity and Mortality Weekly Report. The new data shows that the delta infection resulted in similarly high SARS-CoV-2 viral loads in vaccinated and unvaccinated people, CDC Director Rochelle Walensky said.

“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,” she said in a statement. “This finding is concerning and was a pivotal discovery leading to CDC’s updated mask recommendation.”

While Provincetown wasn’t mentioned in the study, there were widespread reports of an outbreak at the popular vacation and party destination at the tip of Cape Cod.

The events took place in Massachusetts who had traveled to the Cape between July 3 and July 17. Many people with Covid had been in crowded indoor and outdoor events at venues, including bars, restaurants, guest houses, and rental homes.

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