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After being identified in 41 states, the Centers for Disease Control and Prevention upgraded the delta variant of COVID-19 from a “variant of interest” to a “variant of concern.”  According to CDC Director Dr. Rochelle Walensky, the highly contagious variant, otherwise known as B.1617.2, could soon become the dominant strain in the United States.

"I think that that's probably going to be the case," Walensky said in an interview with ABC News. "It's more transmissible than the alpha variant, or the U.K. variant, that we have here. We saw that quickly become the dominant strain in a period of one or two months, and I anticipate that is going to be what happens with the delta strain here."

Initially identified in India in October, the delta variant has been reported in more than 80 countries according to the World Health Organization. The WHO declared delta a "variant of concern" in May, saying variants of concern have shown to spread more easily than others. The delta variant could potentially lead to increased hospitalizations, more strain on health care resources and ultimately more deaths.

“It’s making up about 10% of our cases now. It’s easier to transmit and has a more severe illness than the other strains,” said  Dr. John Greene, chair of Moffitt Cancer Center's Infectious Diseases Department. “It’s more contagious, spreading to more people who are susceptible. The bottom line is we need to get vaccinated or face high community levels.”

It’s more contagious, spreading to more people who are susceptible. The bottom line is we need to get vaccinated or face high community levels.
Dr. John Greene

COVID-19 vaccine efficacy

According to Greene, the delta variant is still covered with the current lineup of approved COVID-19 vaccines.

“But the coverage could theoretically be about 80% instead of 95%,” said Greene. “The people who aren’t vaccinated in the U.S. could end up circulating this big time. If you’re immune suppressed, you may have 20 to 40% protection against the delta variant if vaccinated.”

recent study from Public Health England showed that two doses of the Pfizer vaccine were 88% effective against symptomatic disease from the delta variant two weeks after the second shot. The study also showed that one dose of the Pfizer vaccine was only 33% effective.

Differing symptoms from previous strains

According to the WHO, there have been reports that the delta variant also causes more severe symptoms, but say that more research is needed to confirm those conclusions.

The main symptoms of COVID-19 are a fever, persistent cough and loss of taste or smell. Professor Tim Spector, leader of the Zoe COVID Symptom Study, said top symptoms since the start of May are headache, sore throat, and runny nose. Fever and cough rank fourth and fifth, respectively. According to Spector, the delta variant seems to be working "slightly differently," and that possible COVID-19 infection could feel "just like a bad cold or some funny 'off' feeling."