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Delta Variant

What are the concerns with the Delta Variant?

The delta variant appears to be 50 percent more contagious than the alpha variant, which was first identified in the United Kingdom and became predominant in the United States during the spring. As of late 2019, Alpha was about 50 percent more transmissible than its original variant first identified in Wuhan, China.

What is the effectiveness of the vaccines against this variant?

Based on real-world data, all three vaccines approved for emergency use by the FDA offer strong protection against severe disease and death from the delta variant, although they appear to offer less robust protection against minor to moderate infections.

What about people who are immunocompromised?

While vaccination remains the best way to protect against these viruses, including the delta variant, not all immunocompromised individuals will respond well. Others, however, will develop immunity from the shots, and getting immunized appears to be no harm, according to William Schaffner, medical director of the National Foundation for Infectious Diseases.

Individuals with compromised immune responses should also practice social distancing, wear masks, and avoid crowds, particularly indoors. “These things continue to affect these highly susceptible people,” he said.

Prof. Scheffner said it's also vital for those who are immunocompromised to get tested if they experience symptoms, especially right before the new season of influenza arrives, so they can be treated appropriately - either for flu or for Covid-19. As an example, antiviral medications are sometimes used to treat influenza and monoclonal antibodies may be used to treat covid-19, which can reduce the risk of hospitalization and death when used early in the course of the disease.


Infectious Delta Variant Is Now The Dominant Covid Strain In U.S., CDC Says

According to the latest CDC estimates, the Delta variant is the most prevalent coronavirus strain in the U.S., accounting for more than half of the country's Covid-19 infections over the last two weeks and putting the nation at risk as it fully reopens despite dangerously low vaccination rates in certain regions and groups, including children. 



According to the latest CDC estimates from a two week period between Jun. 20 and Jul. 3, the Delta variant, which was first detected in India and is also known as B.1.617.2, accounts for 51.7% of Covid-19 cases in the U.S.
The Alpha or B.1.1.7 variant, which was first identified in the U.K. and became the dominant U.S. strain in April, now makes up 28.7% of cases. 

Within a month, the Delta variant had spread to become the dominant U.S. variant: it represented only 10% of cases a month ago, and around 30% between Jun. 6 and Jun. 19.


The most common symptoms of delta infection in fully vaccinated people are headache, runny nose, sneezing, and sore throat. Shortness of breath has dropped to 29. Symptoms that were more common in the earlier version of the virus are much less frequent now, including loss of smell at 11 and fever at 12.

The top symptoms of unvaccinated people are headache, sore throat, runny nose, fever, and persistent cough. Shortness of breath is ranked 30, and loss of smell is ranked 9.

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