Originally Published: 28 FEB 21 02:36 ET

Updated: 28 FEB 21 15:24 ET

By Amir Vera, Holly Yan and Christina Maxouris, CNN

    (CNN) -- [Breaking news update at 3:16 p.m. ET]

Vaccine advisers to the US Centers for Disease Control and Prevention unanimously voted Sunday to recommend the distribution of the one-dose Johnson & Johnson's Covid-19 vaccine.

[Previous story, published at 3 p.m. ET]

It's easy to get caught up in all the good news about the Covid-19 pandemic.

A third vaccine is on the brink of getting distributed by the millions. New cases and deaths have decreased since the abysmal January surge. And for the first time since early November, fewer than 50,000 patients are hospitalized with Covid-19.

But even though 7% of the US has now been fully vaccinated, new cases have stopped declining. They're now hovering around 70,000 new cases a day, according to Johns Hopkins University.

That's an improvement over the recent peak of 302,506 infections reported on January 2. But it's still higher than last summer's peak of around 67,000 per day.

Dr. Anthony Fauci said he fears some Americans are easing up on safety measures too soon -- threatening the same post-dip surges we suffered in 2020.

"Just look historically at the ... early spring of 2020 or the summer of 2020, when we started to pull back prematurely. We saw the rebound," said Fauci, director of the National Institute of Allergy and Infectious Diseases.

That false sense of security and rebound led to another wave of shutdowns last year.

But this year, Americans face a new challenge: the increased spread of troubling variant strains -- including some that appear to be homegrown.

That's why health experts say Americans who want to get life back to normal must keep physical distancing -- and get vaccinated as soon as you're able to.

A 1-dose vaccine could be available very soon

On Sunday afternoon, advisers to the US Centers for Disease Control and Prevention will vote on whether the agency should approve the distribution of Johnson & Johnson's Covid-19 vaccine.

The vaccine was already given emergency use authorization by the US Food and Drug Administration on Saturday. After Sunday's vote among CDC advisers, CDC Director Dr. Rochelle Walensky is expected to give the final green light for widespread distribution.

"To have a third vaccine that meets the expectations of an (emergency use authorization) for safety and effectiveness at preventing severe disease and death from COVID-19 brings us one step closer to protecting the American public, staying ahead of concerning viral variants, and finding our way out of the pandemic," National Institutes of Health Director Dr. Francis Collins said.

An FDA analysis found the vaccine safe and effective. It can be kept at simple refrigerator temperatures.

And unlike the other two Covid-19 vaccines already authorized in the US, Johnson & Johnson's vaccine only requires one dose. And that makes it a game changer, said Dr. Esther Choo, a professor of emergency medicine at Oregon Health & Science University.

"It's been such a challenge to get even a single dose to many people," she said. "Signing up for a second one, keeping track of that, getting transportation, it's just a huge barrier for many Americans and then of course in harder-to-reach places, including rural America, it's just been a huge logistical challenge."

Johnson & Johnson will start testing vaccine in children

Now that the Johnson & Johnson vaccine has proven to be safe and effective in adults, the company will begin studies with children, said Dr. Macaya Douoguih, head of clinical development and medical affairs with J&J's vaccine arm, Janssen.

"We will conduct several immunogenicity and safety studies in children from 17 years of age down to neonates," Douoguih told a CDC advisory committee Sunday.

"The study in adolescents, we hope, will open next week. We are also anticipating a study in pregnant women in the second and third trimesters toward the end of March, early April," Douoguih said.

Johnson & Johnson also plans to begin study in immunocompromised individuals in the third quarter of this year, Douoguih said.

The FDA's emergency use authorization for the Johnson & Johnson vaccine is currently for use in adults 18 and older.

The Pfizer-BioNTech vaccine has been authorized for people ages 16 and over, and the Moderna Covid-19 vaccine has been authorized for people ages 18 and over.

Both Moderna and Pfizer have started enrolling children in Covid-19 vaccine trials.

J&J vaccine will 'dramatically' increase vaccine availability

The Johnson & Johnson vaccine will also help boost the number of shots available to Americans as health officials race to prevent another possible Covid-19 surge fueled by variant strains.

So far, more than 48.4 million Americans have received at least their first dose of a Covid-19 vaccine, CDC data shows.

More than 23.6 million people have gotten both doses of a vaccine. That's about 7.1% of the US population.

"The J&J vaccine, which is easier to transport and store... is going to dramatically increase our vaccine availability," said Dr. Jonathan Reiner, a professor of medicine at George Washington University.

About 3.9 million doses will be available for ordering right away, said Lori Tremmel Freeman, CEO of the National Association of County and City Health Officials. That could add about 25% more Covid-19 vaccination capacity for states.

Utah Gov. Spencer Cox told CNN he expects the state will receive "several thousand doses" over the next few days.

"We expect shots in arms this coming week," Cox said. "We know they have about 4 million doses on hand right now ready to go out. They'll start shipping those out, we believe, on Monday. We should have those shots, we think, on Wednesday. And shots in arms on Thursday and Friday. That's a big deal for our state and for Americans everywhere."

West Virginia Gov. Jim Justice said Friday an emergency use authorization for the Johnson & Johnson vaccine would mean the state will receive about 15,000 more doses as soon as this week.

Now is not the time to ditch safety measures

While news of another Covid-19 vaccine is worth celebrating, the US is still a long way off from herd immunity. That's when enough people are protected against a virus that it cannot spread through the population.

More than 48,800 people are still battling Covid-19 in hospitals, according to the COVID Tracking Project. That's down from a record-high 132,447 patients on January 6.

But more than 63,800 Americans have died from Covid-19 just this month, according to Johns Hopkins.

"Over the last few weeks, cases and hospital admissions in the United States have been coming down since early January and deaths had been declining in the past week," said Walensky, the CDC director.

"But the latest data suggest that these declines may be stalling, potentially leveling off at still a very high number. We at CDC consider this a very concerning shift in the trajectory."

Experts have warned another Covid-19 surge could be just weeks away, this time fueled by variants of the virus. Particularly concerning is the highly contagious B.1.1.7 variant first identified in the UK, which the CDC estimates will soon be the predominant strain in the US.

"CDC has been sounding the alarm about the continued spread of variants in the United States, predicting that variants, such as the B.1.1.7 variant, which is thought to be about 50% more transmissible than the wild type strain, would become the predominant variant of Covid-19 by mid-March," Walensky said.

"We may now be seeing the beginning effects of these variants in the most recent data."

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