A study released Monday by the U.S. Centers for Disease Control (CDC) shows mRNA vaccines produced by Pfizer-BioNTech and Moderna are highly effective at preventing COVID-19 in “real world” conditions.
The study was conducted among nearly 4,000 health care workers, first responders, and other essential workers in six states between December 14 and March 13. The results showed the risk of infection was reduced by 80 percent after one dose and 90 percent after two doses.
Speaking during a White House COVID-19 response team briefing, CDC Director Rochell Walensky said the study showed the two vaccines can be effective not only in symptomatic infections but asymptomatic infections as well. She called it “tremendously encouraging,” and said it complements other recent studies in the New England Journal of Medicine and elsewhere.  
But Walensky said that good news was tempered by the lasted virus figures from around the United States.  She said the daily average for infections rose by ten percent over the past week, to nearly 70,000 per day. Hospitalizations were up by more than four percent and deaths by almost three percent.
The CDC chief said the U.S. looks similar to Europe just a few weeks ago, which is now going through another wave of infections.  
She issued a dire warning of a sense of “impending doom” in the U.S. amid an increase in in coronavirus infections and hospitalizations.  She urged people to hang on just a bit longer and continue practicing social distancing and other safety measures.
She said the national vaccination efforts are working. As of Sunday, more than 93 million people received at least one dose of vaccine and more than 51million people have been fully vaccinated in the United States. 
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