Transcript for Masks still required in California until June 15
tonight to the coronavirus pandemic in the U.S. New York now just hours away from lifting its mask mandate, as a growing number of states now follow those new CDC guidelines. But what Dr. Fauci said today if you want to keep that mask on. There's also news tonight on the pfizer and modern vaccines, what they're now seeing against common variants in this country. And the key antibodies, particularly in older Americans after six months. Here's ABC's kayna Whitworth now. Reporter: Tonight, as covid cases and deaths plunge to their lowest levels since the start of the pandemic, health officials want fully vaccinated Americans to know they are safe indoors and outdoors without a mask. Even if you have a breakthrough infection, the chances of your transmitting it to someone else is extremely low. Very, very low. Reporter: But Dr. Anthony Fauci also saying the new CDC guidance doesn't mean Americans have to stop wearing masks. That does not mean that people who feel they want to continue to wear a mask should not wear a mask. There's not a -- it's not a mandate to take your mask off. Reporter: Most states are now racing to drop remaining mask rules, but for the 40 million people in California, masks are still required until June 15th. Leaving business owners like Jonathan Carillo, owner of Maria's deli, to enforce state restrictions. It's so confusing that we enforce the rules for our employees, but the public -- my job is not to police the public, it's kind of, I'm leaving it in their hands to make the decision for themselves. Reporter: Businesses enforcing the mask rules say they've already taken a hit. Membership at this San Diego gym is down 25%. The CEO says masks are one of the main reasons. All of the members who have frozen their membership, the number one reason is the mask. We are definitely, you know, anxiously awaiting for the mask policy to go away. Reporter: For now, many Americans relieved to see the mask rules lifted. It feels really, really good to be able to step out, bring my children out to the park and be able to enjoy that. Reporter: But in North Carolina, the kroboth family isn't ready to ditch the masks indoors or outdoors yet. I feel like we're locked back in the house again. Reporter: All three sons are vulnerable with an autoimmune diseases and right now they're too young for a vaccine. It really hurts because it kind of keeps us all exposed and it can put, like, my brothers and things in danger. Reporter: And tonight, new research showing the effectiveness of vaccines. One study showing that in a lab, the pfizer vaccine appears to work against the California, new York and uk variants. And the modern vaccine also appears to work including in older people against all those variants from South Africa and Brazil with new tra lizing antibodies lasting longer than six months. Of course the data only goes as long as we've had the vaccines actually being used by the American people. Encouraging news, kayna. Those couple of fronts when it comes to the variants and the key antibodies. On the flip side, we learned there's a growing body of evidence tonight showing some concern when it comes to Americans who have immunocompromised conditions or people that take medications that suppress their immune systems. We heard from that family there and we have to stay on this, too. Reporter: Yeah, absolutely, David. So, researchers are finding that depending on your condition, they're not seeing that high level of antibodies that they would expect, but doctors say antibodies are not the only things that protect you from covid-19. So they encourage anybody with these conditions to speak with their physician about the benefits they could still see from being vaccinated. David? All right, kayna Whitworth in California. Thank you, kayna.
This transcript has been automatically generated and may not be 100% accurate.