The Delta variant is now the most dominant strain in the U.S. Here’s where it’s most common

• The Delta variant makes up more than half of COVID-19 cases in the U.S., according to the CDC.

• The variant appears to be most common in the Midwest and the West regions.


• Vaccines should protect you from the Delta variant.

The Delta variant makes up more than half of COVID-19 cases in the US, marking the first time the easily transmissible strain occupies the majority of cases, according to new data.

The Centers for Disease Control and Prevention released new estimates this week that show more than 51% of COVID-19 cases are of the Delta variant.

The variant, which first appeared in India, hit stateside back in March. It represented fewer than 0.1% of cases in April before surging in less than three months, where it made up 51.7% of cases in the US in the last two weeks in July.

Looking back to just two weeks earlier, on June 19, the strain is up from 30.4%, according to data.

Where the Delta variant is most common

The Delta variant appears to be making a significant impact in the Midwest and the West, while it’s less common in the Mid-Atlantic region.

Two states — Arkansas and California — recently warned residents to remain diligent due to recent spikes, but data shows that it’s becoming a threat in several other states.

According to the CDC, the variant is most common in Iowa, Kansas, Missouri, and Nebraska, where it makes up for more than 80% of cases.

A map released by the CDC showing variants in the US. The darkest orange is the Delta variant.

In Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming, 74.3% of cases in those states are of the Delta variant.

In six states, more than 56% of cases are of the Delta variant. Those states are Arizona, California, Hawaii, Nevada, New Jersey, and New York.

The Mid-Atlantic region — Delaware, District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia — had the lowest percentage rates in the country, with the variant making up just 31.4% of all total cases, according to the data.

Will vaccines protect me from the Delta variant?

Research has shown that Covid-19 vaccines are effective against multiple variants, include the Delta variant.

Two doses of AstraZeneca or Pfizer vaccine were 60% and 88% effective, respectively, at preventing symptomatic COVID-19 caused by the variant, according to a UK study from England’s public health authority.

However, recent data from Israel said the Pfizer vaccine is less effective at protecting against infections caused by the Delta variant, but it still can prevent severe illness.

The Pfizer vaccine protected 64% of inoculated people from infection, down from 94% before, according to Israel’s Health Ministry. The vaccine did remain effective at preventing severe illness during the data collection, which was from June 6 to early July, where it was 94% effective, down from 97%.

Johnson & Johnson and Moderna also said their vaccines are effective against the Delta variant.