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What Do Cape Cod Outbreak Numbers Really Say About COVID Risk for Fully Vaccinated?

August 16, 2021

A Delta-powered outbreak in Provincetown, Mass., last month contributed to the Centers for Disease Control and Prevention’s sudden mask guidance update that now suggests even fully vaccinated people wear masks indoors in areas with high COVID-19 infection levels.

A CDC study found 74 percent of the 469 people infected in Barnstable County, which includes Provincetown, were fully vaccinated. And 79 percent of those fully vaccinated cases, known as  breakthrough cases, reported symptoms. Equally alarming, the agency’s researchers found viral loads among 127 fully vaccinated people similar to 84 others either unvaccinated, partially vaccinated or whose vaccination status was unknown.

Unfortunately, many people interpreted the Cape Cod numbers as indicators that, say, 74 percent of all fully vaccinated people are getting COVID. Instead, health officials say that as more people become fully vaccinated, they are more likely to be among those infected. The difference: Unlike the unvaccinated, the fully vaccinated rarely become seriously ill.

Dr. Rochelle Walensky, the CDC director, said only seven hospitalizations and no deaths were reported among the fully vaccinated in the Provincetown outbreak.

“Our vaccines,” she said, “did exactly what they were supposed to do: Prevent severe disease, hospitalization, and death.”

In June, the Israeli health minister said close to half of all infections in the country were among vaccinated people. But 85 percent of Israeli adults were vaccinated.

“The purpose of the vaccine was to actually take a deadly disease and turn it into the common cold,” said Dr. Ulysses Wu, Hartford HealthCare’s System Director of Infection Disease and Chief Epidemiologist. “And the vaccine is working.”

Massachusetts Department of Public Health last week reported 9,969 confirmed COVD-19 infections so far among the state’s fully vaccinated, with 106 deaths. Both of these numbers, the infections and deaths, represent only about 0.23 percent of more than 4.3 million who have been vaccinated.

“We do believe that the vaccination process works,” said Keith Grant, APRN, Hartford HealthCare’s Senior System Director of Infection Prevention. “It’s effective, it’s efficient and it’s safe.”