Know the differences between variant delta and delta plus 2:33
(CNN) -
Defeating this pandemic covid-19 and variant highly contagious delta untreated only protected by the vaccine, it is also inoculate others in the community, doctors say.
"Even if you are vaccinated, if you live in an area with high rates of spread of covid-19, and with the delta variant on the rise, there is a possibility that you can become infected," said emergency physician Dr. Leana Wen, professor guest at the George Washington University Milken Institute School of Public Health.
The delta strain is the most communicable coronavirus variant identified so far, said the head of the World Health Organization (WHO).
It is between 40% and 60% more transmissible than the highly contagious alpha variant (B.1.1.7), according to the European Center for Disease Prevention and Control.
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In the United States, the delta variant has spread to all states.
It is now responsible for more than 50% of COVID-19 cases, the US Centers for Disease Control and Prevention (CDC) said.
"In some parts of the country, this percentage is even higher, especially in areas with low vaccination rates," the CDC said.
"This rapid increase is concerning and threatens the progress the United States has made in ending the pandemic."
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As the delta variant continues to spread, "we know there is a risk of progressive infection" among fully vaccinated people, Wen said.
"So even if he's vaccinated, he could still get infected. Most likely, everyone around him, even if he's vaccinated, gets vaccinated as well."
Covid-19 vaccines continue to be highly effective
Even when people do get breakthrough infections, vaccines still have "very, very high efficacy" in preventing serious illness or hospitalizations, within the 90% range, said Dr. Anthony Fauci, director of the Institute. National Allergy and Infectious Diseases.
There are some doctors who have expressed interest in giving a booster dose of the vaccine to some patients, such as those who may be immunosuppressed, Fauci said Sunday.
What the trajectory of the delta variant in Israel and the UK could mean for the US.
But the CDC and the US Food and Drug Administration (FDA) say that those who are fully vaccinated do not need a booster shot at this time.
"There will always be people, well-meaning people and well-meaning companies who will say, 'You know, from the way we look at the situation, it looks like you might need a boost, so let's go ahead and give a boost.' But that's not one. formal recommendation, "Fauci said.
"The data evolves. You get more information as time goes on. So when you get to the point where you have enough information to make a strong recommendation, that's not a sea change. That's making recommendations as the data evolves. "he added.
In low-vaccination states, more young people are hospitalized
Nationwide, 48% of all Americans have been fully vaccinated, according to CDC data, Sunday.
But a third of all eligible Americans, those 12 and older, have yet to receive a dose of the vaccine.
In Missouri, only about 40% of the population is fully vaccinated.
Doctors say hospital rooms and equipment are running low, especially as more young people are hospitalized with COVID-19.
"We see more people 30 and older getting sicker and requiring hospitalization," said Dr. Mayrol Juárez of Mercy Hospital in Springfield.
"In addition, we have seen that in this wave, each person gets sick faster," he said.
Biden warns unvaccinated about delta variant 1:51
The Missouri State Department of Health estimates that more than 70% of the virus circulating in the state is the delta variant.
About 91% of patients in the intensive care unit at Mercy Hospital in Springfield use ventilators, said managing director Erik Frederick.
"It's shocking for us to have that kind of number," Frederick said Saturday.
"These are young patients, in their 20s, 30s, 40s, again, it's alarming, [and] a direct line to vaccination rates."
Arkansas and Mississippi, also in trouble
In Arkansas, where about 35% of the population is fully vaccinated, the state recently surpassed 1,000 new COVID-19 cases a day, state health officials said.
"Arkansas is on the rise of a third wave of covid-19 here in our state, and it's leaning toward younger folks," said Dr. Cam Patterson, chancellor of the University of Arkansas for Medical Sciences.
"We are also seeing breakthrough infections in immunosuppressed people," he said.
Fauci: Those fully vaccinated against covid-19 do not need a booster dose at this time
And in Mississippi, where only a third of the population is fully vaccinated, "we've seen almost a complete acquisition in the delta variant," said Dr. Thomas Dobbs, a state health official.
New COVID-19 cases and hospitalizations are primarily driven by unvaccinated people, said Dr. Paul Byers, a state epidemiologist.
"Due to the rapid increase in delta variant cases and outbreaks, combined with the low overall immunization rate in the state," Mississippi advises people 65 and older to avoid mass gatherings until July 26, regardless of the time. Vaccination status, the state health official tweeted.
When might we need a covid-19 vaccine booster?
"Americans who have been fully vaccinated do not need a booster shot at this time," the CDC and FDA said in a joint statement Thursday.
"We continue to review any new data as it becomes available and will keep the public informed. We are prepared for booster doses as long as science shows they are necessary," they added.
Some Americans were confused when Pfizer said that immunity has partially waned for some of its vaccine recipients as the delta variant spreads around the world.
Pfizer said it is working to develop a booster dose to protect people from the variants.
"We see a decrease in the efficacy of the vaccine in Israel against the delta variant, but that decrease in efficacy appears to be clustered among the elderly and those who were vaccinated a while ago," said former FDA Commissioner Dr. Scott Gottlieb. and current board member at Pfizer, to CBS's "Face the Nation" on Sunday.
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"With regard to boosters, we are talking about a third dose of the existing vaccine," Gottlieb said.
"Anyone getting vaccinated right now won't need a booster. If you go out and get vaccinated right now, that vaccine will help you through the fall and winter [boreal]. What we're really talking about right now is people who were vaccinated a year ago. time, where there may be a decrease in efficacy, "he explained.
On Thursday, Pfizer said it would soon release data on a third dose of the vaccine and send it to the FDA, the European Medicines Agency and other regulators.
Pfizer said it would seek emergency use authorization from the FDA for a booster dose in August.
Dr. Jerome Adams, the US chief health officer during the Trump administration, said he agrees with the CDC and FDA that fully vaccinated people do not need a booster shot at this time.
"Vaccines are your best option right now," Adams said Friday.
"They are still incredibly effective. And if we have to get a booster, we just have to get a booster. We do that for the flu every year, so people shouldn't worry too much about that."
CDC encourages in-person learning, with safety precautions
With millions of students returning to classrooms in the coming weeks, the CDC said schools should prioritize in-person learning combined with safety measures.
Students, teachers and staff who are fully vaccinated do not need to wear masks at school, the CDC said.
But those who are not fully vaccinated, including children under the age of 12 who are not yet eligible, should wear masks indoors, they said.
The CDC suggests that schools offer COVID-19 vaccines on-site, provide paid sick leave for employees to get vaccinated, and excuse absences for students 12 and older to get vaccinated.
If COVID-19 cases are low in a community and local schools want to move away from pandemic precautions, they should do so gradually, the CDC said in a draft of the guidance obtained by CNN.
"If localities decide to eliminate prevention strategies in schools based on local conditions, they should eliminate them one at a time and closely monitor [with adequate testing] any increase in COVID-19 cases before eliminating the next prevention strategy. "says the guide.
Getting more people vaccinated will help in that effort, many experts say.
CNN's Miguel Marquez, Polo Sandoval, Ben Tinker, Maggie Fox, Aya Elamroussi, Deanna Hackney, Virginia Langmaid, Deidre McPhillips and Lauren Mascarenhas contributed to this report.
