Transcript for Growing concerns over Delta variant
Let's bring in infectious disease specialist and ABC news medical contributor doctor Todd Halloran for more on all this act trailer and happy belated Father's Day to you happy Monday thanks for being here. Thank you or your future. So it. Tell me that we know that Mazda's where garden was packed for this Foo Fighters concert last night nearest productivity rate though he. Is that point 3% the lowest since the start of the pandemic so. In states where positive any raids are that low. Can can we stop being concerned about super spreader events. Well first vote as tugboats something very important who doesn't want to see Dave Grohl a Father's Day. The approved Foo Fighters I would have done anything to Toobin there. And yes I meet New York is kicking but I mean you have less than zero point 3% tax productivity. I'm you had to show proof of vaccination to get it inside. There's no question this is the safe way to go. I want I want to dealt a variant though because it did feel that every time which I've read how good things are going and we have to go but spread so. It's now detected in at least 45 states this is a variant that's more contagious. And we think more potentially affecting young people more than previous strains so. How concerned should we all be about that particularly those in states with low vaccination rates. I think we do have to be concerned I NBC here's their here's the issue basically. A study from the UK showed that if you got two doses of the vaccine there was in 96%. Reduction and in possible invasion from the delta parents who he is vaccines work. The issue courses that you don't get the vaccine in your face to face with a highly contagious Barea. It's about 40% more contagious than the alpha very the one who was first described in the United Kingdom. And we know that that was more contagious and we think there's about a troubled risk of hospitalizations. Since this is just another reason that you really wanna go there and and get the vaccine really important. And we also just learned a little bit more about the plan for the Olympics this summer Japan's says it will allow. Up to 101000 spectators had Olympic events over the summer note cheering allowed which will have to unpack that part. But last Friday that doctor leading Japan's Kobe nineteen response. Published a report urging organizers to hold the events without any spektr's so spectators I should say so. What do you think in his decision and how likely is this whole no cheering rule to actually be put into effect. I mean this is a tough decision OK because remember Japan. Has been surgery so we know they are coming down which is good news the issue is don't want people Farber 6%. Of the population has been fully vaccinated and that's very low. And let's face it needy kids eat snacks give high fives cheer you up to ask the question to the risks outweigh the benefits so here is what I would recommend. If you're fully vaccinated. And you should it show improved food that's the first thing. This the next point. It is dat you wanted to make sure that is pure and you know compromised. Or help those cold morbidity is like obesity or under control diabetes that you really want to make sure that you avoid view event. That's or if you're going to go you really want him Wear a mask especially if you're indoors don't most of the events are old doors and that's a good thing but there are still about half a dozen events that are indoors so really I want to speak to the people who are deemed you don't compromise and I think. In a sense at this point since we're on the fans are probably would avoid that this Summer Olympics at least this round. All right doctor I know it's great to have you thank you. Particularly and.
This transcript has been automatically generated and may not be 100% accurate.