(CNN) — The United States has fully vaccinated more than 100 million people against Covid-19, according to the US Centers for Disease Control and Prevention — a milestone that comes with optimism about the future.

“I think we can confidently say the worst is behind us,” the Dean of Brown University School of Public Health Dr. Ashish Jha said Friday on “Good Morning America.” “We will not see the kinds of sufferings and death that we have seen over the holidays. I think we are in a much better shape heading forward.”

The only thing that could threaten the outlook, he said, was the spread of coronavirus variants, making the push to increase vaccinations even more critical.

Although the vaccination milestone means that nearly 40% of adults have been inoculated, the US still has a ways to go to reach the protection needed in 70-85% of the population to achieve herd immunity, according to Dr. Anthony Fauci. And health officials say that the only way to keep bringing down the death rate is to increase vaccination efforts.

A lower death rate and higher vaccination rate would make it reasonable to target a full reopening by July 1, CDC Director Dr. Rochelle Walensky said Friday.

“We are focused on getting people vaccinated, decreasing the case rates,” she said in a White House Covid-19 press briefing. “If we can continue at this pace, case rates are coming down, vaccinations going up, then I think July 1 would be a reasonable target.”

But, she cautioned, “the virus has tricked us before,” and it will be crucial to keep an eye on cases in the coming months.

CDC pushes both routine and Covid-19 vaccinations for adolescents

As officials look to make vaccines, currently only given to those 16 and older, available to younger adolescents, missed routine vaccinations could cause a problem.

Walensky said routine vaccinations among adolescents are down this year. The need for routine immunizations for children returning to school, the rollout of the annual flu vaccine and the expected availability of Covid-19 vaccines for children 12 and older may present a logistical challenge, she noted.

“It’s going to take a truly coordinated effort among families, health care providers and public health officials at local, state and federal levels to achieve both the rollout of Covid-19 vaccine in adolescents and a rapid catch up of routine vaccinations,” Walensky said at an event hosted by the Pediatric Academic Societies.

Walensky called on pediatricians to aid in the effort.

“To achieve high vaccination coverage rates and reduce Covid-19 transmission, we need rapid and extensive vaccination of children under the age of 18,” she said.

Younger vaccinations have become more important as more older people become inoculated and those reporting infections skew younger.

In West Virginia, the median age for new cases is currently 34 years old, Gov. Jim Justice announced. That is down ten years from a few months ago.

“The average age of somebody infected with Covid-19 has really reduced over the past several months,” said the state’s coronavirus czar Dr. Clay Marsh.

“We know that our 10- to 19-year-old age category is our largest for the positivity rates and spread of Covid- 19,” said Marsh.

“I’m telling our young people out there, I’m telling you as point-blank as I can tell you, that you absolutely should have a valid concern,” said Justice, who urged young West Virginians to get vaccinated.

Justice said the two biggest concerns with young people getting infected is transmitting the virus to others “even if you don’t get sick” and the possibility of ending up with “significant side effects… [for] the rest of your life.”

Most Johnson & Johnson vaccine side effects are ‘nonserious’

The Johnson & Johnson single-dose vaccine had sparked some concern over rare reports of blood clots associated with it, but a new review of the safety data found that only 3% of reported reactions after receiving the vaccine are classified as serious.

There have been a total of 17 incidents of severe blood clotting while also experiencing low blood platelet levels, according to the CDC report published on Friday.

The report noted that the safety profile of the vaccine so far has been similar to what was seen in clinical trials, but safety monitoring during the vaccine’s rollout quickly identified the blood clot incidents.

“A rare but serious adverse event occurring primarily in women, blood clots in large vessels accompanied by a low platelet count, was rapidly detected by the U.S. vaccine safety monitoring system,” CDC researchers wrote in the report. “Monitoring for common and rare adverse events after receipt of all COVID-19 vaccines, including the Janssen COVID-19 vaccine, is continuing.”

The data included 88 deaths reported after vaccination. Among those deaths, three occurred in patients with cerebral venous sinus thrombosis and CDC researchers wrote that, after preliminary reviews, “no other deaths appear to have an association with vaccination.”

The-CNN-Wire™ & © 2024 Cable News Network, Inc., a Time Warner Company. All rights reserved.

Join our Newsletter for the latest news right to your inbox