ATLANTA - In a tone sharply different from the optimism of two weeks ago, CDC Director Dr. Rochelle Walensky warned the delta COVID-19 variant is spreading with "incredible efficiency," and now makes up 83% of the virus circulating.
"We are yet at another pivotal moment in this pandemic with cases rising again, and some hospitals reaching their capacity in some areas," Walensky told reporters.
Walensky says the US is averaging 37,700 new cases a day, up 53% from last week, and hospitalizations are up 32%, deaths up 19% week-to-week.
"The delta variant is much more aggressive and much more transmissible than previously circulating strains," Walensky says. "It is one of the most infectious viruses that we know of and that I have seen in my 20-year career.
With just under half of Americans now fully vaccinated, health officials are urging those still on the fence to talk with someone they trust about the vaccine.
"Talk to your healthcare provider," Walensky says. "Talk to your pharmacist. Talk to your friends and neighbors who have gotten vaccinated, and get your questions answered. If you are not fully vaccinated, please take the delta variant seriously. This virus has no intent to let up and it remains in search of the next vulnerable person to infect."
Walensky acknowledges a growing concern among fully vaccinated Americans about breakthrough infections.
The vast majority of US hospitalizations and deaths have been in unvaccinated individuals.
Walensky says breakthrough infections are rare, but they can occur because no vaccine is 100% effective.
Studies show the Pfizer and Moderna mRNA vaccines offer 95% and 94% protection against symptomatic COVID-19, and the Johnson & Johnson offers about 72% protection against the more transmissible delta variant.
Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, was asked whether J & J vaccine recipients should consider talking to their doctor about getting a booster shot of one of the Pfizer or Moderna vaccines.
"There is no reason to believe right now that people who have taken the J & J vaccine are in need of a booster dose of any sort," Dr. Fauci says.
Dr. Walensky says the CDC is not planning to change its mask guidance and recommend masks for vaccinated individuals.
She said those who live in areas of high disease transmission and low vaccination rates may need to take extra precautions.
Last week, Los Angeles County, home to 10 million residents, mandated masks in indoor public settings, even for people who are fully vaccinated.
"If you're unvaccinated, you should absolutely be wearing a mask," she says. "If you're vaccinated, you have exceptional level of protection from that vaccine, and you may choose to add an extra layer of protection by putting on your mask, and that is a very individual choice."
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