Studies show breakthrough infections are rare in fully vaccinated healthcare workers

US health officials say 16 to 20 million Americans are now rolling up their sleeves each week, with 2.5 to 3 million getting vaccinated a day.

Two new studies published online in the New England Journal of Medicine found the Moderna and Pfizer prevented all but a handful of breakthrough infections in thousands of fully vaccinated health care workers and staff at hospitals in Texas and California.

People are considered "fully vaccinated" once they are at least two weeks out from their final dose of the COVID-19 vaccine.

In one study of 8,121 vaccinated healthcare workers at the University of Texas Southwestern Medical Center, only 4 of those who were at least 14 days out from their second dose tested positive for the coronavirus.

Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Disease, says the research shows the vaccines provide a high level of protection.

"So, every day, we get closer and closer to that extraordinary degree of effectiveness that we're seeing at the community level," Fauci says.  "At the end of the day, that is what it is that is going to end this pandemic in this country."

Federal health officials say 70% of Americans age 65 and older, the highest risk group for deadly complications of the virus, have now had at least one dose of the COVID-19 vaccine.

But, with only 13% of US adults fully vaccinated, CDC Director Dr. Rochelle Walensky says the US still has a long way to go in getting people protected.

"I emphasize how we have to wait in there just a little bit longer," Dr. Walensky says.  "Because we can see a time, in the next couple of months, where we will have a lot more people vaccinated, and we will really be able to block infection rates."

One challenge is driving down the level of virus circulating in the community.

The US is averaging about 55,000 new cases each day, the CDC says.

"When you're at that level, I don't think you can declare victory and say we've turned a corner," Dr. Fauci says.  "You've got to continue what we're doing."

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