Five Things To Know About The Delta Variant

A newer strain of COVID-19 is causing concern as cases are rising across the United States. The Delta variant began spreading more rapidly and making news around the middle of June. Now, health experts are warning of another surge of COVID-19.

Here's what health experts have learned about the Delta variant:

1. Delta variant is highly contagious.

The first Delta case was identified in December 2020, and the strain spread rapidly, soon becoming the dominant strain of the virus in both India and then Great Britain. By the end of July, Delta was the cause of more than 80% of new U.S. COVID-19 cases, according to Centers for Disease Control and Prevention (CDC) estimates.

The World Health Organization (WHO) has called this version of the virus “the fastest and fittest.” The CDC labeled Delta as “ a variant of concern,” using a designation also given to the Alpha strain that first appeared in Great Britain, the Beta strain that first surfaced in South Africa, and the Gamma strain identified in Brazil. (The new naming conventions for the variants were established by the WHO as an alternative to numerical names.)

According to the CDC, as of July 22, 2021, the Delta variant accounted for more than 80% of new cases in the U.S. Health experts say it's typical for a new strain of a virus to be more contagious because it often becomes much more efficient and easily transmitted.

2. Delta variant symptoms are the same.

The symptoms of the Delta variant appear to be the same as the original version of COVID-19. However, physicians are seeing people getting sicker quicker, especially for younger people. Recent research found that the Delta variant grows more rapidly – and to much greater levels – in the respiratory tract.

Typically, vaccinated people are either asymptomatic or have very mild symptoms if they contract the Delta variant. Their symptoms are more like those of a common cold, such as cough, fever or headache, with the addition of significant loss of smell.

3. Delta variant is affecting unvaccinated people more.

People who have not been fully vaccinated against COVID-19 are most at risk.

Most patients hospitalized are people who have not received the COVID-19 vaccine. Nationally, 97% of patients hospitalized with COVID-19 are unvaccinated, as of July 22. Vaccines are highly effective at preventing COVID-19 infection and are also effective in fighting against the Delta variant.

In the U.S., there is a disproportionate number of unvaccinated people in Southern and Appalachian states including Alabama, Arkansas, Georgia, Mississippi, Missouri, and West Virginia, where vaccination rates are low. (In some of these states, the number of cases is on the rise even as some other states are lifting restrictions because their cases are going down).

4. Breakthrough cases for vaccinated people are rare, but still happen.

When a vaccinated person tests positive for COVID-19, most either have no symptoms or have very mild symptoms, and it rarely results in hospitalization or death. Their symptoms are more like those of a common cold, such as cough, fever or headache, with the addition of significant loss of smell.

As of July 22, there were 65,000 breakthrough cases (or people who are vaccinated but got COVID-19) among the 160 million people who are fully vaccinated. That's 0.04% of vaccinated people reporting breakthrough cases. No vaccine is 100% effective. With the COVID-19 vaccines averaging about 90% efficacy, health experts expect about 10% of those vaccinated could be infected.

5. Delta variant could be catastrophic is some communities.

In communities with lower vaccination rates, particularly rural areas with limited access to care, the Delta variant could be even more damaging. This is already being seen around the world in poorer countries where the COVID-19 vaccine isn't as accessible. Health experts say the impact could be felt for decades to come.