Johns Hopkins Biocontainment Unit Medical Director Dr. Brian Garibaldi joins Yahoo Finance’s Zack Guzman to break down the latest coronavirus developments as the race for a vaccine continues.

Video Transcript

ZACK GUZMAN: As we've been tracking, things had been improving on the coronavirus front over the last few weeks. But this week, a marked break from that trend, as we saw daily cases rise earlier in the week and yet again yesterday, hitting 36,932 cases across the nation. That was up by about 7,000 versus the same day a week ago. And as we've seen that, a lot of concerns about whether that's tied to the return to schools or congregating after, again, another three-day weekend here after Labor Day. So a lot to discuss on that front, as well as vaccine development here.

And joining us now to discuss both of those things with us is Dr. Brian Garibaldi, Johns Hopkins Biocontainment Unit Medical Director. And Dr. Garibaldi, thanks for coming back on here. I guess we'll just start with your take on that worrying uptick in cases, because we had been doing so well in getting those down. What do you attribute that maybe recent move to?

BRIAN GARIBALDI: Yeah, I think we're all concerned that this might be the beginning of the second spike that we've seen after holiday weekends like Labor Day. It's still not clear how much transmission might be happening in schools, and whether or not that's making its way to the community. So I think those are the two big factors that we're all worried about. But I think we're going to know, over the next week or two, if we're really going to see this big spike after Labor Day that we were all worried about. I mean, we've been gearing up for it.

ZACK GUZMAN: Yeah, I mean, when we talk about one of those areas that has been doing well, obviously New York City is on its-- on its trend line here. It's moved very slowly in reopening. Indoor dining still not going to be allowed till the end of the month, despite the fact that positivity rate is among the lowest in the nation.

But even then, Mayor de Blasio here kind of waffling on getting back to in-person public school openings, that getting delayed among concerns here that maybe things are tied to children going back to school. So what do you make about that and how it could be a signal of what we've seen at higher education levels? We saw UNC backtrack after having students come back to campus as well. I mean, is that kind of the rolling ball here that's expected the farther along we get in the school year?

BRIAN GARIBALDI: We're going to be going up and down until we have a vaccine, whenever that is. You know, I think colleges are obviously a little bit different than elementary schools, because elementary school students are not having frat parties on the weekends and going out to bars, right? So-- but there are different challenges that are presented by-- by young children.

And I think one of the reasons behind the delay in school opening is simply that the infrastructure that needs to be in place to try to keep not just the students safe, but, you know, many of the teachers, who themselves have preexisting conditions and want to be as safe as they possibly can be with the limitations of older schools that have poor ventilation and large class sizes. I mean, I think a big part of this is just wanting to make sure that when kids go back the infrastructure's in place to do it as safely as possible.

ZACK GUZMAN: Yeah, I mean, if we have elementary school students throwing frat parties here in 2020, we've got bigger problems to worry about here. But Dr. Garibaldi, on the timeline here for the-- or for the vaccine, since that really is what is the driving force for when this recovery will actually take hold for sure, I guess we had-- we discussed yesterday kind of different timelines that we got from the CDC, as well as the president here. You listened to the head of the CDC saying that it could be Q2, Q3 before most Americans are able to get it.

The president still saying that he sees the timeline here by election day to get this vaccine out. So on that front, I mean, we got the update from Moderna saying that it's on track to produce 500 million to a billion COVID vaccine doses yearly, so that seems good, but also that they're not going to get their preliminary data out from that phase III trial until December, which would be much slower than its rivals Pfizer and BioNTech working on theirs to get their data out by October. So I mean, when you at all of these pieces moving, what is the timeline, in your eyes, that people should be bracing for?

BRIAN GARIBALDI: Yeah, I think as we've said all along, November has always been a very aggressive and aspirational deadline. I think it's really unlikely that we're going to have data that's widely available and been properly vetted for us to know number one, if the vaccine is safe, and number two, what its clinical efficacy is. And then even if we did have a vaccine from any one of the current vaccines that are under study, no single manufacturer at the beginning is going to be able to supply the number of doses that would be needed to treat the entire-- or to vaccinate the entire American population, so we're really looking at tiered vaccinations.

And I think we've started to see what those plans might look like, prioritizing front line health care workers and people who are particularly at risk for severe disease or death from the vaccine. But I do think Dr. Redfield's timeline is probably more reasonable. If you have a vaccine that looks like it's going to get approved sometime in the winter, It's going to be till spring or summer of 2021 before it's widely available for the population. And I think it's also really important to remember that we're talking about-- you know, we're comparing vaccines to masks and physical distancing.

You know, the FDA has set the bar at about 50% efficacy for a vaccine to be approved, right? So even if there is a vaccine that's, quote unquote, "effective," it's unlikely that it's going to eliminate all disease, and it may not eliminate disease at all. It may just temper the disease and make it either less severe or lasts for a shorter period of time. So I do think what we control now is the ability to play it smart and to socially distance where appropriate, to wear masks, and to avoid crowds until we have this under control.

ZACK GUZMAN: Yeah, and that's really the interesting thing, too, here when you hear President Trump discussing those two things, masks versus vaccine. He did also say Dr. Redfield made a mistake by saying that masks might be more useful here than a vaccine. The president reiterating that vaccines are much more effective in battling against coronavirus than masks.

But when you think about how many Americans are hesitant to actually go out there-- assuming we will get a vaccine approved and meeting that FDA threshold, more and more Americans not really hot on the idea of going out and getting a vaccine here when we look at over the last few months, we've seen a majority of Americans worried about the speed that this is getting rushed out, and a third saying that they might not necessarily want to get that vaccine if it comes to market. So I mean, those are just a few things that I think might be overlooked here on that front.

But lastly, just wanted to ask you a little bit more about what we heard from Dr. Fauci, because in a recent interview with Jennifer Garner-- he's been making the rounds-- he had noted about vitamin D and a new study out from University of Chicago Medicine looking at the efficacy here in vitamin D, vitamin C helping boost the immune system to reduce the odds of actually getting infected with COVID-19. He said he takes those supplements. Do you think that that could actually be a key piece of this in protecting people?

BRIAN GARIBALDI: Well, I think it's hard to say. You know, vitamin D deficiency's pretty common in the US. You know, by some estimates 30%, 40% of the adult population in the country is vitamin D deficient and certainly is related to immune system function. And there are many associations between vitamin D levels and severity of disease in other contexts. And there's emerging evidence of these associations with people who are vitamin D deficient might be more likely to have a positive COVID test.

And there's a small study that's shown there's an association with severity of disease. What's unclear is whether or not if you take vitamin D that will actually either prevent you from getting sick or making you less severely ill. So you know, I think vitamin D certainly has a pretty good safety profile in terms of supplements and vitamins. So you know, I think if you have a reason to be on vitamin D, if you're vitamin D deficient, it would be great to think about repleting it. Being outside actually helps the body make vitamin D into its active form so--

ZACK GUZMAN: Yep.

BRIAN GARIBALDI: --that's something that probably has been an impact as we've socially distanced and many people have stayed inside. And you know, as the winter months come and there's less sun outside, or even in areas that aren't getting a lot of sunlight because of what's happening with fires, I think that could potentially be an issue. So you know, I think if you're vitamin D deficient, it's not a bad idea to replete.

ZACK GUZMAN: Yeah, it's all the more important here, as you said, as we approach those winter months, too, especially considering a lot of these projections here from medical experts, your guys included in that, for how bad things could get by the end of the year. But Dr. Brian Garibaldi, always enjoy chatting with you on this front. Nobody better to dig through all of this. Thanks again for coming on.