(CNN)The country continued this week on a path to reopening from the Covid-19 pandemic, with major population centers such as New York and California pulling back on restrictions following increased vaccinations and lowered infections.
Yet with overall vaccination rates in the US slowing this month when compared to highs in April, health officials are raising awareness about the uneven distribution of vaccines in different parts of the country.
"I'm very unconcerned for people who have been vaccinated, and I'm more concerned for people who have not been vaccinated and the communities that are largely unvaccinated," Andy Slavitt, former White House senior adviser for the Biden administration's Covid-19 response, told CNN's Don Lemon on Wednesday.
Slavitt, who earlier described the Delta variant, or B.1.617.2, as "Covid on steroids," noted people who are in high vaccination areas are likely to know others likeminded about inoculations, and places with few vaccinations are more susceptible to clusters of Covid-19 infections.
"In those communities, a Covid that spreads twice as fast is not a good thing," Slavitt said.
The Delta variant, a form of Covid-19 first identified in India, has increased to approximately 10% of coronavirus cases in the United States, according to the Centers for Disease Control and Prevention.
The strain has been listed by the CDC as a "variant of concern," meaning scientists believe it is more transmittable and can cause more severe disease.
Recent studies demonstrated the effectiveness of vaccines against variants such as Delta, with many in the health community urging to Americans that the best way to defend against Covid-19 is preemptive vaccination and immunization.
"It's one more reason for people to take this seriously and say, 'Wow, we've got great vaccines, we're so lucky to have them, maybe I should take one or two,'" Slavitt said.
Pharmacist Anais Martinez prepares a Covid-19 vaccine to be administered April 9, 2021, at Holy Spirit Catholic Church in Horizon City, Texas.
Recent study points to long-term dangers of Covid-19
This week, the US surpassed 600,000 deaths since the coronavirus pandemic began, according to data compiled by Johns Hopkins University, meaning approximately one in 550 Americans have died from Covid-19.
The rate of infection and deaths in the country have slowed dramatically since the 2020 holiday season, which is largely credited by health experts to the millions of Americans who have since received vaccines. Despite the improved outlook toward beating the pandemic, the risk of contracting Covid-19 remains for many who have not yet been vaccinated.
In an analysis of nearly 2 million people who had a Covid-19 diagnosis between February and December 2020, a new white paper study from FAIR Health points to the dangers of contracting Covid-19 and how symptoms for some can last well beyond what is hoped for after surviving the infection.
Nearly a quarter of Covid-19 patients, 23.2%, had at least one post-Covid condition 30 or more days after their initial diagnosis, according to the study posted on Tuesday.
While post-Covid conditions were found to a greater extent in patients who had more severe Covid-19, they were also found in a "substantial" share of asymptomatic cases.
Half of patients who were hospitalized with Covid-19 had a post-Covid condition 30 days or more after their initial diagnosis, as did 27.5% of those who had symptoms but were not hospitalized and 19% who were asymptomatic.
Pain and breathing difficulties were the top two conditions cited. Most of the post-Covid conditions studied were more common in females, yet there were 12 conditions that were more commonly experienced by males.
One of these, cardiac inflammation, the researchers call "notable" as the age distribution was skewed towards a younger cohort. The largest share -- 25.4% -- of patients reporting this condition were in the 19- to 29-year-old age group, a number that was also disproportionate to the age group's share of Covid patients overall.
FAIR Health says it believes this is the largest population studied for post-Covid conditions and the study was not formally peer-reviewed but was evaluated by an independent academic reviewer.
Rare heart-related risk after vaccination resolved in days, study finds
While a risk of heart inflammation following vaccination for younger individuals is being examined by federal health officials, prompting discussions during a recent FDA committee meeting over how to prepare for vaccinating for children under the age of 12, another study found that such symptoms resolved themselves within days.
Wednesday's report in the American Heart Association's journal Circulation suggests that myocarditis, an uncommon condition that causes inflammation in the wall of the heart muscle, after vaccination may be temporary and straightforward to treat.
Seven patients, all of whom were male and between the ages of 19 and 39, hospitalized with a myocarditis-like illness after vaccination were reported to the CDC's Vaccine Adverse Event Reporting System.
Diagnosis of the conditions was confirmed through testing and all had stable vital signs. Treatment for the patients involved heart drugs known as beta-blockers and anti-inflammatory medication, and the patients were discharged from the hospital within two to four days.
"The clinical course of vaccine-associated myocarditis-like illness appears favorable, with resolution of symptoms in all patients," wrote the team led by Dr. Christopher deFilippi of the Inova Heart and Vascular Institute in Virginia.
"Given the potential morbidity of Covid-19 infection even in younger adults, the risk-benefit decision for vaccination remains highly favorable," they added.
Outreach for vaccinations continues
About 147.8 million people, or 44.5% of the US population, are fully vaccinated, according to CDC data released Thursday.
Fifteen states have hit the Biden administration's goal of vaccinating 70% of adults with at least one dose by July 4.
To reach out to the many who remain unvaccinated, health officials continue to promote new ways to convince Americans of the need to inoculate.
The US Department of Health and Human Services will enlist student ambassadors 16 years and older to help promote Covid-19 vaccination, HHS Secretary Xavier Becerra said Wednesday.
"We want to use those students who want to be ambassadors to their fellow students to get them out and get vaccinated," Becerra said at a roundtable with Anacostia High School students in Washington, DC.
Governors and state officials have also turned to financial incentives during the vaccination rollout, with several states promoting lotteries for vaccinated people to boost interest, even in places that have done relatively well with vaccination efforts.
On Wednesday, Maine announced a sweepstakes that will reward one vaccinated winner with $1 for every person vaccinated in the state by July 4.
The cash winnings increase by $1 for every Maine resident who receives at least one dose of the Covid-19 vaccine, so "the more people vaccinated, the higher the prize," according to a statement from Governor Janet Mills' office.
"Maine is a national leader in Covid-19 vaccination thanks to the more than 876,000 people who have already rolled up their sleeves," Mills said, adding that residents ages 12 and up who have received at least one dose of a Covid-19 vaccine can enter for a chance to win.
According to the release, as of June 15, 74% of eligible Maine residents have received at least one dose of a Covid-19 vaccine, and Maine ranks third among states in the percent of eligible residents who are fully vaccinated.
