Moderna says its coronavirus vaccine is 94.5% effective against Covid-19. Dr. Brian Garibaldi - Johns Hopkins Biocontainment Unit Medical Director joins Yahoo Finance Live to weigh in on Moderna's latest break through and discuss the rise of coronavirus cases across the world.

Video Transcript

- Welcome back to Yahoo Finance Live. The markets today catching another boost from vaccine optimism as that continues to grow with Moderna self reporting more than 94% effective rate here for its experimental COVID-19 vaccine candidate. That slightly tops what we saw from Pfizer earlier this month, but despite that hope building in the distance the current pandemic continues to worsen here every day in the US.

The nation, as a whole, reporting about 150,000 cases a day and states are responding with more stringent responses, including a statewide lockdown taking effect across the entire state of New Mexico today. For more on where we're at in battling all this, we're joined once again by Dr. Brian Garibaldi. He's a Johns Hopkins Biocontainment Unit Medical Director and one of the doctors from the team that helped President Trump battle his own case of COVID-19 earlier this year.

And Dr. Garibaldi it's good to be chatting with you again. I want to start on the vaccine front, because of course, we've been talking a lot about Moderna's candidate today. The FDA announced that threshold back earlier this year that 50% efficacy was really what they were going to go for in approving these. 90% for Pfizer and now 94% from Moderna. But if the goal's herd immunity here, which some might take about 60% of the nation getting immunity, walk us through the numbers of why that number, in terms of the efficacy rate being now at 90% and above, why that's so important when you consider half of America is still a little on the fence here about actually getting vaccinated.

BRIAN GARIBALDI: Well, I think we should be all encouraged by the results that have come out from Pfizer and Moderna. You know, these are new types of vaccines that are, you know, have never really been used before widely, and so the fact that we now have two-- albeit preliminary results. We haven't seen all the data from these trials. They're both really encouraging, much greater effectiveness at reducing coronavirus in patients who receive the vaccine than we could have expected. So this is very encouraging and going exactly as you would hope. If we're hoping to get vaccines widely available in the coming months.

We still need to be very careful about how we message, you know, the effectiveness of these vaccines, being transparent about the process whereby we're going to review the safety data before these vaccines get approved. That I think the FDA really needs to think about, you know, what the best way to approach the approvals are. You know, we do have some data from surveys that people are a little bit less willing to take a vaccine that is approved under an Emergency Use Authorization as opposed to a full FDA approval. So I think, I'm sure the agency will be thinking about that as they review the data and think about next steps in terms of approving use vaccines for wider use.

- From a, from a policy perspective then when we're talking about herd immunity and that being the goal here, or maybe saving those most susceptible in the rollout we're gonna be seeing here, is it as simple to say, look, if you vaccinate everybody and you have a 50% efficacy rate you're going to be fine there in achieving herd immunity. Now if you have 90%, you only need to vaccinate half the country. How should people be thinking about those numbers?

BRIAN GARIBALDI: Yeah, so it's a little bit more complicated than just the efficacy of the vaccine, because the, the way you calculate herd immunity depends on not just characteristics of the virus, but what we're doing in terms of our own behaviors and actions to try to reduce the spread of the virus. So the good news is that if it's highly effective, then we may only need to have 65% 70% of the country get vaccinated. If it was only 50% effective, then we would need to have even greater numbers of people get vaccinated in order to protect those of us who are not getting vaccinated for whatever reason.

So these numbers are really encouraging, but it doesn't change the, the notion that we want to have with this particular virus, probably around 65% 70% of the population having immunity by any means, either by prior infection, or if through a vaccine in order to try to really tamp down the spread of the virus.

- Doctor, what about the length of the immunity? I mean, that seems to be a big question mark that's still out there. I mean, you know, it's great that it's 90% 95%, but if it's only about a two-month, three-month period, how effective can that be?

BRIAN GARIBALDI: Well, we don't know yet how long immunity is gonna last. I mean, there have been cases of people who have had coronavirus infection who have then have gotten second infections, but there haven't been many cases of that. And there have been few cases where they've actually proven that it's a completely different virus that you got infected with, and that it wasn't just residual, you know, RNA from the virus that's being picked up by our very sensitive tests.

So I think the first step is can we stop the widespread transmission of the virus and even if you only have a vaccine that lasts for let's say, six months to a year. That would be incredibly effective at doing that, but we need longer term data to understand is the protection that, that folks receive from this vaccine is it going to last for several years, and what the frequency with which we would need to re-vaccinate people, or give booster shots if that's gonna be necessary. We don't know yet.

- How should we be looking at this from a global perspective? We've heard the likes of WHO, even the Gates Foundation coming out and saying it's great if all Americans get the vaccine, but, of course, you don't have walls up at the borders. And so the developed countries can all have it, but what if the vaccine is not distributed to some of the, the developing nations. I mean, how do you think that complicates that, the way we look at the ability to control the virus from a global perspective?

BRIAN GARIBALDI: Well you're exactly right. This is a global problem, right. You know, this didn't start-- you know, if there is virus circulating in any country, every country is at risk of potentially having resurgences of the virus. And so when we think about how to distribute these vaccines, obviously, we're, we're first focusing on this first tier that we've set up in the United States, which-- which will include vulnerable populations, front line workers, and essential workers. But that's only the first step, right.

We, we need to make sure that we're thinking about how to distribute this globally. This is a global problem and it continues to be an issue. Obviously, the United States has been leading in cases and leading in deaths, but there are a number of other countries that are not too far behind and the virus needs to be controlled in those countries as well.

The good news is that, you know, these are the first two vaccine candidates that now have efficacy data for them and we're still waiting to see the final, final results, but there are many other candidates coming down the pipeline. So hopefully we'll, we'll be talking about how to distribute these vaccines, not just how many countries, but how many different vaccines will be available that, that we can then try to distribute.

- And Dr. Garibaldi as you're talking about that, obviously, this is an issue that's not only global, but also one that we're gonna be battling until the vaccine is rolled out. And in the next couple months, here, we've already seen stats rising in terms of hospitalizations past the peak. We've seen cases rise past the peak, now deaths.

As that trail's also getting up to where we saw that wave earlier back in the summer, but talk to me as a doctor who helped the president battle this himself, still talk to me about the treatment options that are now out there as well. Because it sounds like researchers are looking at an arthritis drug that's also been shown in at least one study here to drop mortality by more than two thirds. And obviously there are other steroids that you use president, as well. So talk to me about that, and how doctors have more tools here, and where deaths could go if they have those tools available.

BRIAN GARIBALDI: Well we're hoping that we'll not only continue to expand the drugs that we can use for patients who get sick en-- sick enough to be hospitalized. And Baricitinib is, is a drug that was approved for rheumatoid arthritis that's being actively studied in combination with other drugs, like Remdesivir to see if together they can further improve outcomes. So that hopefully we'll get some more data from a large US, and actually, international study on that in the coming weeks.

There also are a number of different drugs where we're looking at potentially improving outcomes among people who get diagnosed, but are still outpatients. Right, I think, given how many people are becoming infected, this battle against the virus is not gonna be won in the hospital. It's gonna be won in outpatients.

Number one, by reducing transmission, both with our own behaviors, wearing masks, socially distancing. But also potentially a vaccine, but also some exciting therapeutics that we're hoping to get more data on that might prevent you from getting the virus if you are exposed to someone, but as important, prevent you from becoming really sick and hospitalized if you're diagnosed, but still well enough to be an outpatient.

- Yeah, I'm glad you mentioned that piece because it is the overall goal, and it's obviously the easiest way, you know, wearing a mask, making sure that people don't get infected in the first place, so you don't need to worry about drugs, or hospitalizations, or anything like that. But the big question now as we see states locking down again, seems to be what's going to happen around Thanksgiving if cases are this high. We had a doctor on last week talking about maybe it's not too soon to think about canceling Thanksgiving plans.

How worried are you about that as we have families coming together, intergenerational chances here to pass the virus. Talk to me about why that might be something Americans might need to think about.

BRIAN GARIBALDI: Well, we need to be careful in, in how we plan our celebrations, right. There's this, you know, this false sense of comfort that you get just-- you're, you're hanging out with friends or family members that you know well that somehow they're gonna be safer than the average person on the street, in terms of being a risk to, to give you the virus. I think we need to be really, really careful. We need to avoid large gatherings. We need to be very mindful about who we're spending time with, particularly, you know, intergenerational families, as you mentioned. You know, older folks are certainly at higher risk from severe disease or death from this virus.

I think we're all very worried as we head into the flu season that we're going to see-- we're already-- I mean, the house is on fire. So, you know, but we're worried that it's gonna get a lot worse as people are gonna be traveling across state. College students are gonna be coming home and mixing with people from across the country. So I think this is a really high risk time, and, and I think we need to be really mindful of what we're planning for the holidays and recognizing that the light at, light at the end of the tunnel is not a train. It's a vaccine, and, and hopefully we're gonna be able to start getting back to some more normal activities.

But it's gonna be several months. We're not gonna be ready to, to have a normal Thanksgiving, or a normal Christmas, or New Year's celebration because the virus is just too far out of control right now in the country.

- All right Johns Hopkins Biocontainment Unit Medical Director Dr. Brian Garibaldi. Appreciate you coming back on the chat.

BRIAN GARIBALDI: Thanks very much. Stay safe everyone.

- You too.