LOS ANGELES (NewsNation Now) — As millions of Americans become fully vaccinated against COVID-19, California officials say the state is on track for a wide reopening on June 15 — meaning large events will be returning just in time for summer.

Their neighbors in Las Vegas have already started their process by welcoming large crowds for concerts. Vaccination status or a negative coronavirus test within 48-hours are required to get in.

“I don’t think the vaccination card is that crazy of an idea,” said Vegas visitor Zachary Puentes.

In California, healthcare leaders are urging people to still remain masked in certain situations.

Dr. John Brooks, Chief Medical Officer for the CDC COVID-19 Emergency Response, says vaccination will be the key for others to go maskless anywhere in the U.S.

“Well, essentially, vaccinated people can do pretty much everything — as long as with a few exceptions,” said Brooks. “So for instance, if you’re a person who is immunocompromised, or maybe taking medicine, that might weaken your immune system, you need to talk to your health care provider because there is some evidence that perhaps vaccination in these persons who by the way should be vaccinated, but it may not always be as effective for them as everyone else.”

According to California officials, after June 15, the major reopening will happen across the state. The new guidelines line up with the CDC’s latest recommendations, meaning no capacity limitations, no physical distancing restrictions for attendees, customers and guests. Fully vaccinated people will not need face coverings in most settings.

The state will have restrictions on travelers coming from countries that have severe outbreaks, but there will be no quarantine requirements for travel within the country.

For outdoor events with more than 10,000 participants, the state is recommending verification of vaccination or a negative coronavirus test, or a mask required to attend.

At indoor venues with more than 5,000 guests, the state is now requiring verification of vaccination or a negative coronavirus test to be maskless.

“You know, you have to still follow the local rules and regulations in your jurisdiction where you’re living,” said Brooks. “And with travel, you’re going to have to keep wearing masks during travel. That’s an all-public conveyance.“

The statewide changes don’t mean that local public health jurisdictions can’t put in stricter guidance based on their conditions. Los Angeles County leaders say they will align with the state’s grand reopening plans.

Brooks also says the CDC is working on new guidelines for children since those 12-15 can now get the Pfizer COVID-19 shot. He stresses that, regardless of the vaccination status, people should still wear a mask while using public transportation. 

The question still remains about booster shots. Dr. Anthony Fauci, the nation’s leading infectious disease expert, says scientists are still trying to determine if an additional shot could be needed later this year to ward off possible variants of COVID-19.