Transcript for Highly contagious COVID-19 delta variant in 41 states
Now to the coronavirus in this country and the new warnings about the delta variant seen in at least 41 states. Highly transmissible. The question now, could it become the dominant strain in this country? Also the emergency meeting tomorrow after some 300 cases of a hard condition in some young people, myocarditis. What you need to know on that and this fast-moving variant. Dr. Jha is standing by the answer your questions. And tonight here the numbers 175 million people have had a dose of the vaccine now. That's 62% of everyone 12 years and older in this country. Here's ABC's Stephanie Ramos. Reporter: Tonight with the highly contagious delta variant now confirmed in 41 states, a blunt warning from the white house covid team. If you're fully vaccinated, you're protected. But if you're unvaccinated, you're at risk of getting seriously ill or spreading the disease to others. Reporter: Experts warn the delta variant is spreading fast and could soon become the dominant strain. Across the south, where vaccination rates are lowest, health officials are sounding the alarm. If this thing gets uncorked you're looking at transmission we've never seen. Reporter: It comes as a CDC advisory panel gets ready to hold an emergency meeting tomorrow on about 300 reports of heart inflammation, myocarditis. Among the 20 million adolescents and young adults who have been vaccinated. 16-year-old Noah Hiers in Alabama was vomiting with flu-like symptoms after his second pfizer shot. Two days after my vaccine that night, I had cleared up and I felt fine, no symptoms at all. I went to sleep that night and woke up with chest pain. Reporter: He says that pain went away the next morning, but he was hospitalized. Noah's doctors think the second vaccine dose might have caused temporary heart inflammation. There's a lot more risk in having covid. There's a lot more long-term risk, and as far as we know, there's zero long-term effects from this, so 100% would still get the vaccine. Let's get to Stephanie Ramos with us. Stephanie, I know there's also news tonight the Biden administration today announcing a big investment in potential anti-viral treatment for covid going forward? Reporter: Right, David. The department of the health and human services says the government will invest more than $3 billion to develop and manufacture anti-viral pills to treat covid. They can be taken at home early on in infection to prevent serious illness, much like anti-virals taken now for the the government says its goal is to have this treatment available within a year. David. It would be encouraging as well moving forward. Steph, thank you.
This transcript has been automatically generated and may not be 100% accurate.