Map shows how almost all the US counties where COVID-19 is surging have vaccination rates below 40%

• 173 US counties have COVID-19 cases above 100 per 100,000 people, per new CDC data.
• Almost every one of those counties has vaccinated fewer than 40%, the CDC director said.
• The unvaccinated are "particularly at risk" from the Delta variant, she said.

The overwhelming majority of counties where COVID-19 cases are surging have low vaccination rates, according to data from the Centers for Disease Control and Prevention (CDC).

Speaking at a press briefing on Thursday, CDC Director Dr. Rochelle Walensky said that cases rates in 173 counties had exceeded 100 infections per 100,000 people.

That is about three times the national average of about 32 per 100,000, according to CDC data.

Of the counties where cases were high, almost all - 93% - had vaccinated under 40% of their populations, she said.

Here is the map of counties where cases have surged over to or above 100 per 100,000 as of July 2:

And the map of counties less than 40% vaccinated. The two match almost precisely. (Counties are greyed out if no data is available.)

The average number of daily new COVID-19 cases in the US rose by 11% in the week ending July 6 compared to the week before, Walensky said.

This rise is likely driven by the highly transmissible Delta variant, which now makes up more than half of the cases in the US.

Real-world data shows that the Pfizer, Moderna, and AstraZeneca COVID-19 vaccines remain effective against Delta, as Insider's Dr. Catherine Schuster-Bruce reported.

For instance, data from the UK shows that two shots of Pfizer vaccine can give 88% protection against symptomatic COVID-19.

However, people who have not been vaccinated "remain susceptible, especially from the transmissible Delta variant, and are particularly at risk for severe illness and death," Walensky said.