(CNN)A coronavirus variant first identified in India is "like Covid on steroids," Andy Slavitt, former White House senior adviser for Covid-19 response, said Wednesday.
"(The Delta variant) is a more virulent strain," Slavitt told CNN. "This is like Covid on steroids. You can be around people for less time and still get exposed."
The Centers for Disease Control and Prevention has labeled the Delta variant a "variant of concern," a designation given to strains of a virus that scientists believe are more transmissible or can cause more severe disease.
The CDC says the variant accounts for about 10% of coronavirus cases in the United States.
Slavitt said the variant provides people with one more reason to get vaccinated.
"If you have been vaccinated, you have very little to worry about," he said.
Surgeon General Vivek Murthy told CNN on Tuesday the Delta variant "is rapidly increasing here in the United States."
He said there is data that indicates it might cause more severe illness.
"That still needs to be understood more clearly, but these are two important concerns and they explain in part ... why this has become the dominant variant in the UK, where over 90% of cases are the Delta variant," Murthy said.
The good news is that vaccines appear to be effective against the variant.
A new study by Public Health England found that two doses of a coronavirus vaccine are "highly effective against hospitalization" caused by the variant. The study found the Pfizer/BioNTech vaccine is 96% effective against hospitalization after two doses.
Pfizer CEO Albert Bourla said during CNBC's Evolve Global Summit that he feels "very good" about the vaccine when it comes to variants of concern, but the company has a system in place in case a variant emerges that requires a more tailored vaccine.
Murthy said there isn't enough data to indicate the effectiveness of Johnson & Johnson's one-dose vaccine in regard to the Delta variant, but the vaccine has shown it can help prevent hospitalizations and deaths when people are infected with other strains.
"The key is get vaccinated, get both doses," Murthy said.
As of Wednesday, 44.1% of the total US population was fully vaccinated while 52.7% has received at least one dose of a vaccine, according to the CDC.
Thirteen states -- with the addition of Hawaii on Wednesday -- have fully vaccinated more than half of their residents, the CDC says.
This comes on the heels of the US surpassing 600,000 deaths since the coronavirus pandemic began, according to data compiled by Johns Hopkins University. That means about one in every 550 people in the US has died from the virus.
States continue to reopen
So far, 14 states have reached Biden's goal of vaccinating 70% of adults with at least one dose by July 4, according to CDC data.
New York is among the states that reached that milestone, pushing Gov. Andrew Cuomo to lift most state-mandated Covid-19 restrictions.
Restrictions were lifted across all commercial and social settings, including the requirements on social gatherings, capacity restrictions, social distancing, health screenings, cleaning and disinfection protocols, and contact tracing. Mask requirements will continue in pre-K settings, on public transit and in health care settings, Cuomo said.
Fireworks displays were put on at various locations across the state Tuesday night to celebrate essential workers and the lifting of restrictions.
"This is a momentous day, and we deserve it because it has been a long, long road," Cuomo said. "We can now return to life as we know it."
California lifted most of its Covid-19 restrictions Tuesday, ending capacity limits, physical distancing and mask requirements for the vaccinated.
Businesses in the state are already adjusting.
The Abbey Food & Bar in West Hollywood brought back dancing, DJs and sitting at the bar for a party to celebrate the end of restrictions. Major League Baseball's Los Angeles Dodgers held a "Reopening Day" promo, with 25,000 Justin Turner bobbleheads, to welcome back a full capacity home crowd.
Meanwhile in Maryland, Gov. Larry Hogan said his state will lift Covid-19 restrictions, including mask requirements, and the state of emergency on July 1. Businesses may still enforce their own requirements, Hogan said.
Maryland has vaccinated 72.3% of its adult population with at least one dose so far, CDC data shows.
Delaware is getting there, with 68.3% of adults having received at least one dose, Gov. John Carney said. He added that his state expects to its Covid-19 state of emergency order on July 13.
"Get vaccinated. Ask your friends and family if they've received their shot. These vaccines are extremely safe and effective," Carney said.
Getting more shots into arms
Pediatricians are stepping up to not only vaccinate newly eligible children and teens against Covid-19, but adults as well.
One month after Sandhills Pediatrics in Southern Pines, North Carolina, started offering the Covid-19 vaccine, the practice administered 940 doses of the Pfizer vaccine -- 268 went not to patients, but adults over the age of 23.
Dr. Christoph Diasio, a pediatrician at the office, said he offers the vaccine to most patients and their family members.
"I've seen every reaction from arms crossed, basically jumping away from me; 'There's no way I'll get that,' to 'I've been meaning to -- I just haven't been able to get it scheduled yet with work,'" Diasio told CNN.
His office has been offering other routine vaccinations, like the flu shot, to family members of patients for years. He says the practice is fairly common among pediatricians nationwide and can provide some protection for babies who are too young to receive the vaccine themselves.
Mental health has improved among adults, Census survey says
Adults in the United States are feeling less depressed than they were at the height of the pandemic, but mental health is improving at uneven rates, according to the latest Household Pulse Survey published by the Census Bureau.
Through late May and early June, more than 40% of adults said that they felt "down, depressed, or hopeless" for at least several days in a week. That was down from more than half of adults who said the same in January at the peak of the pandemic in the US.
Depression remains highest among adults under 30, and it's not improving as quickly as in other age groups. About 56% of adults under 30 said they experienced feelings of depression in a recent week, according to the latest survey data compiled between May 26 and June 7, down from about 65% at the height of the pandemic.
People in this age group are twice as likely than others to experience those feelings frequently, with about 1 in 5 adults under 30 saying they are depressed "nearly every day."
Since January, nearly all demographic groups have seen improvement in the rates of feelings of depression. But for people who said that they or someone in their household experienced loss of employment income during the pandemic, the rates have increased slightly, up from 64% to 66%.
