Dr. Sanjay Gupta Answers Your Covid-19 Questions: Coronavirus podcast for June 9

(CNN)Washing masks. House visits. Summer travel. CNN Chief Medical Correspondent Dr. Sanjay Gupta tackles some recent questions on these topics from our listeners and more.

You can listen on your favorite podcast app, or read the transcript below.
Dr. Sanjay Gupta: There's no question the coronavirus has reshaped the way we all live our lives. Can you even imagine the life we have now compared to six months ago? All along I've been getting so many questions from our listeners about how to best adapt to this new normal.
    Over the last several months, the questions have really changed. They've become much more specific.
      From washing masks, house visits, summer travel, just navigating your way through life. So today I wanted to try and tackle some of those questions.
      I'm Dr. Sanjay Gupta, CNN's chief medical correspondent. And this is "Coronavirus: Fact vs. Fiction."
      Ashlee Fromm: How do you know that heat actually kills Covid-19?
      Gupta: I know why people are asking the question. Summer is almost here, and we're hoping that this pandemic will be over soon as a result.
      But the thing is, it's probably not going to go away just because of the warmer weather.
      We do know that other viruses in the same family generally survive for less time in warmer temperatures, but experts say it's still too early to tell if this is going to make a dent when it comes to the spread of Covid-19.
      If you look at a map of the world and find places right now with the warmest climate, it's become clear that the virus is still spreading in those areas.
      Additionally, what researchers will tell you is the primary factor currently driving transmission is less about the weather and more about our current lack of immunity to Covid-19.
      As we develop more and more immunity over the years to come, we may have better protection in a seasonal variation. But that's not the situation now.
      So even if we do see the spread slow down a little bit over the next few months, we can't count on summer heat to deal with this pandemic — the responsibility is still going to be on us to prevent ourselves from getting infected and from infecting others.
      We all have to behave like we have the virus.
      Allison Springer: I read that many Covid deaths, the patients were deficient in vitamin D. Would you recommend people having additional vitamin D?
      Gupta: Well, currently there is no evidence that suggests that vitamin D or hyperdosing on vitamin D is going to protect us against Covid-19.
      Experts do recommend that we get enough of the recommended daily dose of vitamin D. But not any more, and not any less.
      For most people over the age of 1, that recommended daily dose in the United States is 15 micrograms a day. That's a very small amount. It's easy to double-check this — just look at the label of your vitamin bottle.
      But for those over the age of 70, it can be slightly higher. But these recommendations can also vary from place to place, country to country, so check them out wherever you live.
      I just want to take a second and explain what vitamin D can and cannot do.
      There's no question vitamin D is essential for healthy muscles, strong bones. It also helps your immune system fight off viruses and bacteria.
      So don't get me wrong. Vitamin D is good for you — but taking higher levels of it will not reduce the risk of the virus and could, in fact, be dangerous. Too much vitamin D can lead to a toxic buildup of calcium in your blood, which could sometimes cause heart rhythm problems and kidney damage.
      So you've got to remember you want to take the right amount — again not too little, but not too much.
      Margaret Pearson: How often do I need to use a fresh mask? Should I have a freshly washed cloth mask every time I put one on?
      Gupta: This is a great question and until this pandemic is over, we are going to have to get used to wearing masks as we go out and about our regular lives.
      So let's go through some of the best practices when using different types of masks.
      Now as a practicing surgeon, I've been wearing masks for 30 years. I'm very used to them. But I typically wear them just in the operating room.
      What the CDC [US Centers for Disease Control and Prevention] is recommending is that surgical masks and N95 masks are kept for health care professionals on the front line. While there are no longer the extremely critical shortages of masks, we still need to make sure that our health care workers have an adequate supply.
      For the general public we're really talking about wearing cloth masks. Try and keep one handy every time you go out of the house, and then try to avoid touching it or removing it until you return. It's hard, I know. People are constantly adjusting the mask. But if you're doing that, it kinda defeats the purpose. Because you might get the coronavirus on your hand and then accidentally infect yourself.
      If possible, try and wash the mask after every use. It's a good idea to keep a few masks around to be able to achieve that.
      Generally, paper masks are only meant to be used once. There isn't exactly a time limit on how long you can wear one, but if your mask feels very damp or it's dirty, or obviously if it's damaged, you need to replace it.
      But if you think it can be reused, you can try disinfecting it in a pretty simple way: just leaving it in a clean, safe place in your home for a few days. After that, it should no longer be infectious, because studies show that the coronavirus can only survive on surfaces for up to several hours or a few days.
      Remember, the whole point of using masks is so that when we go out in public and we can't physically distance with each other, we can at least reduce the likelihood that we are spreading the virus into the environment.
      You wear the mask mostly to protect those around you.
      Springer: Wondering if you recommend wearing eye protection while traveling. I know that the NBC medical adviser believes he contracted the virus through his eyes while flying to New Orleans.
      Gupta: The thing is, it's very difficult to know if he contracted Covid on the airplane or somewhere else. If you look at the evidence for the virus spreading through the eyes, there's not a lot of it.
      The CDC says that the virus mainly spreads through the nose and mouth.
      According to experts, spreading through the eyes is possible, but there's no proof of how likely that is yet.
      Nevertheless, you're likely to see some airlines, like Qatar Airways, for example, requiring crew members to wear goggles, in addition to masks and gloves.
      On a flight, wearing goggles can't hurt, especially if it might stop you from touching your eyes, which is a big problem. And in case you're curious, just wearing glasses alone won't really be enough to shield your eyes from viral transmission.
      But don't forget the basics. The most important things are the same: Wear a mask, wash your hands regularly and don't touch your face or eyes. You might have the virus on your hands and that's how you accidentally infect yourself.