...if vaccines are safe and effective?

Ever Wonder? / May 26, 2021

...if vaccines are safe and effective?

avatar of Shira Shafir

As time goes on, it’s getting easier to get a COVID-19 vaccine—in many places in L.A. County you can now just walk up to a vaccine site without an appointment. Millions of Californians have already gotten their Fauci Ouchie, but it’s also okay to have questions about the vaccine.

Do you ever wonder if vaccines are safe and effective?

This very question came up when we last talked to Kenneth Phillips—if you haven’t listened to his episode about contact tracing yet, be sure to check it out. Ken recommended that we talk to Shira Shafir (@IDPhD), a professor and infectious disease epidemiologist at the UCLA Fielding School of Public Health. She’s also working with the L.A. County Department of Public Health to help train contact tracers. She answered all our questions about the vaccines, from how scientists and doctors know they’re safe to when we might be able to start vaccinating younger kids.

Have a question you've been wondering about? Send an email or voice recording to the podcast team to tell us what you'd like to hear in future episodes.

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Perry Roth-Johnson (00:06):

Hello! This is Ever Wonder? from the California Science Center. I'm Perry Roth-Johnson. As time goes on, it's getting easier to get a COVID-19 vaccine—in many places in L.A. County you can now just walk up to a vaccine site without an appointment. Millions of Californians have already gotten their Fauci Ouchie, but it's also okay to have questions about the vaccine. Do you ever wonder if vaccines are safe and effective? This very question came up when we last talked to Kenneth Phillips—if you haven't listened to his episode about contact tracing yet, be sure to check it out. Ken recommended that we talk to Shira Shafir, a professor and infectious disease epidemiologist at the UCLA Fielding School of Public Health. She's also working with the L.A. County Department of Public Health to help train contact tracers. She answered all our questions about the vaccines, from how scientists and doctors know they're safe to when we might be able to start vaccinating younger kids. Let's get into it. Shira Shafir, you are a professor in the departments of Community Health Sciences and Epidemiology at the UCLA Fielding School of Public Health. Welcome to the show!

Shira Shafir (01:20):

Thanks! It's an honor to be here with you.

Perry Roth-Johnson (01:22):

Devin Waller's here too—co-host of the show—you're back again. Hi Devin!

Devin Waller (01:25):

Hey Perry. Great to be here. And hi, Shira. Thanks so much for joining us.

Perry Roth-Johnson (01:29):

So, Shira, we have a lot of questions for you about COVID vaccines and their safety and effectiveness. But, you know, before we dive into those specifics, can we just start with some basics about your background in epidemiology? Like what does an epidemiologist study and what does that help us understand?

Shira Shafir (01:46):

Sure. So in general, an epidemiologist studies the distributions and determinants of disease—which is a really fancy way of saying what we try and look at is: who gets disease, and where disease happens, and when disease happens. And then we use all of that information to try and ask and answer the question, why does disease happen?

Devin Waller (02:06):

So, yeah, like you're a disease detective. Like you're trying to figure out where it came from, how it occurred, how it spreads, things like that.

Shira Shafir (02:14):


Devin Waller (02:15):

I understand that during the pandemic, you've been helping the L.A. County Department of Public Health with their contact tracing program. So what was your role in the program? What did you do?

Shira Shafir (02:26):

Yeah, so, um, UCLA and UCSF, in partnership with the California Department of Public Health, have been working to train people throughout the state to work as contact tracers and case investigators. Um, and it's a massive initiative to, to bring people who don't really have a background in public health, make sure they understand about the epidemiology of COVID about the importance of contact tracing, and then help them develop the skills to actually do the work. Um, so I have two functions in that initiative. The first is serving as, uh, one of the faculty subject matter experts and helping provide information and context and knowledge about the epidemiology of COVID. But the second is that I help lead the monitoring and evaluation part of the project, where we make sure that we are actually training people well, and they are learning the things we know are going to be so critical to protect the health of the population of California.

Perry Roth-Johnson (03:21):

In addition to contact tracing, uh, what other tools do we have to control respiratory diseases like COVID-19?

Shira Shafir (03:29):

The good thing is we have a lot of different tools at our disposal. Um, and prior to the authorization of the incredible vaccines that we currently have, the tools that we relied on, um, were: social distancing—so staying at least six feet away from, from any other person with whom you did not live, um, as well as masking, good hand hygiene and cough etiquette. Um, and then really leaning on contact tracing and case investigation, so we could try and break chains of transmission of infection.

Devin Waller (04:02):

Let's talk about vaccines. Why is vaccination one of our best tools for controlling the pandemic?

Shira Shafir (04:08):

Vaccines are really nothing short of a scientific miracle. Because what we're able to do with these vaccines is we can really train the body so that, um, if a person gets exposed to the virus, the body has a response ready and says, "I'm not going to let this virus make, make my person sick." Um, and so one of the reasons it's most effective, whereas with masks, you have to wear a mask the right way, every single time. With social distancing, you have to make sure you're six feet away from the people you don't live with all the time. And so there's just this constant, um, need to, to redo and refresh. With vaccines, once we get someone fully vaccinated and they develop this immunity, they're protected. Um, and not only that, the sort of the next level of incredible is that when we have enough people as individuals who are protected, there's a level of protection that comes to the entire community.

Perry Roth-Johnson (05:05):

What's the buzzword we keep hearing about the community level of protections? Is that what we're calling herd immunity?

Shira Shafir (05:12):

Yeah, it's what we call herd immunity. You'll hear sometimes people talk about it as community immunity. It's this idea that if you have enough people who are vaccinated and who are immune, then the chance that someone who is infectious—so who's capable of transmitting the virus—the chance that they'd come into contact with someone who is susceptible or capable of getting infected, that chance is so low that you're not going to have sustained transmission of the infection in a community.

Devin Waller (05:43):

Is there a magic threshold, a percentage that we're aiming for when it, when it comes to herd immunity?

Shira Shafir (05:50):

So that's a really tough question to answer. Um, and part of the reason is we actually have an equation that we use to calculate what percentage of the population we believe needs to be immune in order to achieve herd immunity. And one of the major factors in that calculation is, how transmissible is a virus? One of the things we know is—as we've seen the introduction of these new variants in the United States—so as these variants appear to be more transmissible, it changes our understanding of what we will need to achieve in order to see herd immunity. The other thing that's really important is, you know, it's not like a light switch. So if I were to say, the number is 80%, it's not like the minute we get 80% of the population vaccinated, the virus is done and we can all be burning our masks. It really relies on an equal distribution of people who are vaccinated throughout the entire community. Um, and that's very hard to achieve because one of the things we know is that we will often see pockets of populations that are unimmunized or under immunized.

Perry Roth-Johnson (07:01):

So it sounds like, you know, we still have local effects that if the 30% of people in L.A. County who haven't been vaccinated yet all live in the same city, then that city's going to be vulnerable to future outbreaks?

Shira Shafir (07:14):


Devin Waller (07:15):

So, I want to shift into some questions about safety. Understandably safety is a huge concern. The COVID vaccines were made in record time, which has made some people a little uneasy. So can you shed some light on how scientists were able to develop these vaccines so quickly, relatively speaking, but yet still keep them very safe?

Shira Shafir (07:35):

That's a great question. And I think one thing that's really important to remember when we think about the timeline—work on coronavirus vaccines actually started in 2003, when we had the first SARS outbreak.

Perry Roth-Johnson (07:46):


Shira Shafir (07:46):

So we shouldn't really think of it as we, we found a COVID-19 vaccine in ONE YEAR. We should think of it as it took 17 YEARS to develop a COVID-19 vaccine!

Devin Waller (07:56):


Shira Shafir (07:56):

Um, and, and when you use that timeframe, it doesn't seem like it happened so fast. Um, the other thing to remember, the two things that really limit the speed of vaccine development are: money—so having enough money to do research and development and run clinical trials. That wasn't really an issue in, in 2020 when, um, pharmaceutical companies were being given all of the financial resources that they needed in order to support that research and development. And the other thing is the, the speed at which people are getting infected—because all of the calculations, in terms of understanding if the vaccine works, means we design these trials, where half of the people in the trial get the vaccine.

Shira Shafir (08:40):

And half of the people in the trial get a placebo, which is something that, you know, it's a saline injection, it's an inert substance. And then we look to see how many people get COVID in each group. So when we see more transmission, people end up getting the disease much faster, and that shortens the timeline. So really importantly, in the development of these vaccines, there were no corners that were cut. There were no steps that were skipped. It's just that they were able to work so much faster because the two rate-limiting factors that normally exist were not an issue in this circumstance.

Devin Waller (09:19):

Early in the pandemic, we heard a lot of news about clinical trials and all of the testing that the vaccinations went through. How did we test safety and effectiveness during these trials?

Shira Shafir (09:31):

So here in the United States, um, that's sort of overseen by the Food and Drug Administration, or the FDA. And there's a prescribed sequence in which testing has to happen. So it starts out with, what's known as phase one clinical trials. We also call these "first in humans." So prior to a phase one, uh, the vaccine or the vaccine candidate is only given to laboratory animals or in cells. And if it is shown to be safe in those trials, then we start phase one. They're really, really small. We look at, um, you know, 10 to 30 people and just look to see if, if it appears to be safe. After phase one, we go to phase two, which again is an enhanced safety trial. So, uh, up to a hundred people at this point, and we look to see if there are any complications or adverse reactions. If anything is seen—and when scientists look at it, if they believe that it's being caused by that vaccine candidate—it doesn't get to move forward in the process. Then we do phase three clinical trials and phase three clinical trials typically have tens of thousands of people when we're doing them for vaccines. Half the group gets the vaccine candidate, half the group gets the, um, the placebo, that inert substance. And we look really for two things at that point, are there any adverse events or complications that are happening? And if there are, the trial can be stopped where they investigate those more intensely and try and figure out, is this something that happened BECAUSE the person received the vaccine candidate? Or is it something that happened AND the person happened to receive the vaccine candidate? Really trying to understand correlation versus causation, which is a big part of what epidemiology does.

Shira Shafir (11:19):

Um, so if they go through that phase three clinical trial process, and it shows in that group of people that the vaccine works—people were vaccinated or less likely to get disease—and that it's safe. They go to the FDA, um, to receive authorization or approval. Um, and then the vaccine gets released onto the market. They still do continued surveillance once it's out on the market. And we have a system in the United States called VAERS—the Vaccine Adverse Event Reporting System—so that if anybody believes they've had an adverse event associated with the vaccine, they report it to the Centers for Disease Control, and it gets investigated.

Devin Waller (11:57):

On that note, can we talk a little bit about the Johnson and Johnson vaccine? Why was it paused from use? And just recently, we heard, unpaused?

Shira Shafir (12:07):

Um, in the case of the Johnson and Johnson vaccine, it appeared that there was a risk of a very specific type of blood clot that people would develop. And it happened, uh, at a rate of about one in 1 million shots. And it was really important for the FDA to, to pause the distribution of the Johnson and Johnson vaccine. Again, to understand if that was a correlation or it was a causation. So was it something that was just happening in the population and people had happened to have received the vaccine? Or, was it something that the vaccine was actually increasing their risk? So a couple things happen during that pause. The first was that, um, the FDA and the CDC were able to look into it and try and determine if there was a causal relationship. The second is that it really gave time for the government to notify physicians that there's a chance this relationship existed—they should be aware of it, they should look for it, and if they believe it has happened, they should know how to treat it. And after all of that investigation, and after that awareness raising, ultimately what the Food and Drug Administration decided was that the benefits of using the Johnson and Johnson vaccine far outweighed any potential risk that there may have been for this specific type of blood clot. And I think when we talk about the benefits, number one, it's the only one that we have to use in the United States that requires just one shot. And it also can be stored very differently, making it much better for mobile outreach campaigns, people who live in rural areas, that it might be more difficult for them to come into a clinic. And because it's only one shot, people develop immunity faster. So there might be reasons we want someone to be immune on a shorter timeline. Maybe if they have a medical procedure or, um, you know, something big is happening, we want them to be immune as quickly as possible.

Devin Waller (14:14):

So in that case, uh, would you, would you say that the system worked as intended?

Shira Shafir (14:21):

Absolutely. You know, it, this seems to happen in about one in a million shots. Well, the clinical trial only has 40,000 people. There's no way they were going to see it in the clinical trial. So that's the reason we do this, you know, surveillance after it's on the market to make sure with certainty that these vaccines are safe. So you're exactly right. The system is working the way it was intended. Um, and while it may have been a little bit frightening for people to hear about this pause, what I would hope is that people actually take reassurance from the fact that the pause happened. That the government was taking it seriously, was investigating and taking the necessary steps to ensure that the tools we have to help control the pandemic are as safe and effective as is possible. The good news is right now in Los Angeles County, we have sufficient supply of all the vaccines. And if someone, for whatever reason, um, doesn't feel like they themselves want to receive the Johnson and Johnson vaccine, there's certainly the opportunity to book for Pfizer or Moderna instead.

Perry Roth-Johnson (15:31):

Right. Right. Totally. I mean, that, that actually is a nice segue into my next question. Kind of looking ahead to the future, you know, now that we have good vaccine supply—everyone 16 years old and up is eligible—um, many folks are starting to think what's in store for younger kids? Uh, it seems like there's two cohorts of kids that I hear talked about in the media. There's the 12 to 15-year-old adolescents. And then there's the under 12 years old—I think it goes down to six months. What can we expect for these two cohorts of kids in the coming months?

Shira Shafir (16:03):

So, um, you know, I'll say we're recording this on, on May 6th. And, uh, every indication is that next week, uh, the vaccine will be authorized for those adolescent and young adults, the 12 to 15-year-old population. Because the dosage that's being, uh, given that has, was studied is the exact same for that group. Um, as soon as the FDA provides—extends that emergency use authorization—12 to 15-year-olds will be able to receive the Pfizer vaccine. So I think really encouraging and really amazing. By mid-May, 12 years and up, will all be eligible, um, to get vaccinated with Pfizer. And ultimately what that means is I think there's a really good chance that, um, sort of junior high and high school will be able to return to in-person instruction in the fall with all of the students and all of the teachers vaccinated.

Devin Waller (17:03):

So important.

Perry Roth-Johnson (17:03):


Shira Shafir (17:03):

Which is amazing! The other thing is that, uh, Pfizer indicated this week that they are hoping to be able to have their trial done in six-month-old to 12-year-old kids by November. And they will seek emergency use authorization by December. So, um, I, I think it's entirely possible that at least for the Pfizer vaccine, we will be able to start vaccinating everybody over the age of six months at the beginning of 2022. Um, if anyone has questions about that zero to six month group, um, there's now really compelling evidence that has come out. Um, if a person who's pregnant gets vaccinated against COVID in their third trimester, then antibodies get passed to that developing fetus. And the baby when it's born is going to be protected from the maternal antibodies for the first six months. So really what that means is by December, if we're vaccinating people who are pregnant and we have the approval to give the vaccine in six-month-plus, that means that, you know, for the beginning of 2022, we're going to have vaccines hopefully available for everybody in the population.

Perry Roth-Johnson (18:17):

Are the current vaccines good enough to keep us safe from, from the current, like variants of concern that we're seeing circulate in the community, um, or might we need new versions later on?

Shira Shafir (18:28):

I think probably the answer to your questions is yes and yes.

Perry Roth-Johnson (18:30):


Shira Shafir (18:30):

All of the data that we have right now. And we actually just got some very encouraging data about both Pfizer and Moderna yesterday from real-world trials. All of the data that we have right now suggests that the vaccines that we have do protect well, although not perfectly, against the variants that are of concern, the ones that we currently see. As we have transmission and a lot of transmission of SARS-CoV-2, the virus that causes COVID-19, the virus just makes a lot of mistakes when it's copying itself. And if, when it's making these mistakes, it, um, it lands on a mistake that sort of gives it an advantage or increases its transmissibility, then that variant, um, will persist. So the vaccines that we have do currently protect against the variants. But there is a concern that a variant would arise that perhaps our vaccines don't protect well against. Um, one of the incredible things is that, uh, both Pfizer and Moderna are currently doing trials to see if boosters would be necessary or changing the sequence would make it more effective. Um, and so, you know, we're, we're kind of preparing for both possibilities.

Devin Waller (19:50):

You know, that's a really interesting conversation. We've heard a lot of chatter about boosters. What is it about certain viruses that do require an annual or a periodic booster?

Shira Shafir (20:00):

Yeah, so, um, in infectious disease epidemiology, we would talk about that as the "immunogenicity" of the virus. So how good is the virus at inspiring our body to mount a strong, robust and lasting immune response? And it's different for every virus. Um, you know, there are some vaccines, you, you, it's kind of one and done, right? You never have to get that again. Um, but one of the things we want every year is for someone to get their influenza shot. Part of the reason we need to get a new flu shot every year isn't because influenza isn't immunogenic. It is. The reason is because the flu virus changes. And if it changes enough from year to year, then, then we essentially don't have the right cells that we've made to respond to the virus as it exists. Um, so you know, it very much depends on the property of the virus itself, whether or not, you know, it's stable and it doesn't change.

Shira Shafir (21:04):

Um, as well as our immune systems, you know, how strong is the response we mount to that virus? So it oftentimes can be a combination of both of those two factors. And, and right now, we don't have an answer about whether or not we're going to need booster shots. All of the data suggests right now that the immune response to the vaccine lasts AT LEAST seven months.

Devin Waller (21:29):


Shira Shafir (21:29):

Um, and you'll notice the wording I use—at least, not at most. And seven months might seem a little strange, but that's the amount of time we've accumulated that we've now been able to track individuals who participated in the clinical trials.

Devin Waller (21:43):


Shira Shafir (21:43):

So it's entirely possible that next month that data is going to change. And we're going to be able to say at least eight months, then at least nine months.

Perry Roth-Johnson (21:52):


Devin Waller (21:52):

Makes sense, yeah.

Shira Shafir (21:52):

And you know, there, there's no shortcut around that. The only way to know the answer is to have time pass.

Devin Waller (21:59):

Shira, as we wrap up, can we just address some common questions and maybe some misconceptions that we've heard floating around? Here's one. So I've heard some vaccines have virus in them. Can I get COVID-19 from the vaccines that are out there?

Shira Shafir (22:13):

You cannot get COVID-19 from the vaccines that exist. None of them have the live virus and it's the live virus that someone would need in order to get COVID-19.

Perry Roth-Johnson (22:25):

I think J&J has something called an adenovirus—and that came from a chimpanzee?

Shira Shafir (22:31):

From a chimpanzee!

Perry Roth-Johnson (22:32):

Is that why you can't get COVID-19? Because it's, it's not the virus that causes COVID-19 that's in J&J?

Shira Shafir (22:38):

Exactly. It's not the COVID-19 virus, it's an adenovirus—sort of these common cold viruses. And they chose a chimpanzee common cold virus, because if they used a human cold virus, then you'd get a human cold while you were developing your protection, and that's pretty crummy!

Perry Roth-Johnson (22:54):

Yeah, yeah.

Shira Shafir (22:54):

So they chose the virus that could not make people sick, but they could insert the information for the spike protein. So that spike protein would be made, um, even though it doesn't have enough of the COVID-19 virus to cause COVID-19 at all.

Perry Roth-Johnson (23:13):

Right, right. That's actually a good segue into the next common question. Um, you know, we hear that there are a lot of side effects—especially with the final dose if you get one of the mRNA vaccines, Pfizer or Moderna. I mean, I'll just share after I got my second Moderna shot, I had chills for maybe 12 hours, you know, the following day. It wasn't anything unmanageable. But why does the vaccine sometimes make people feel sick? And why does it seem to be worse for younger people like me?

Shira Shafir (23:40):

Yeah. So in general, we are really only seeing those side effects from the second shot in people under the age of 60. Um, and, and part of that is because the, that group of people has sort of stronger, more robust immune systems. Um, so why it can make us feel crummy is because our body is responding to something that it says shouldn't be there.

Perry Roth-Johnson (24:05):


Shira Shafir (24:05):

And the reason we feel crummier on the second shot is because on the first shot, that's the first point where we recognized this thing—this spike protein, that shouldn't be there—and we made the immune cells. On the second time, our immune system was like, "Wait! I've already seen this!"

Perry Roth-Johnson (24:23):

Hold up!

Shira Shafir (24:23):

"I know this shouldn't be there. Let me respond even more!" Um, and, and you're right, you know, a lot of people, those under the age of 60, feel pretty crummy for a few hours after getting their second dose of the vaccine. Um, what I would encourage people to understand is it's way, way better than getting COVID itself.

Perry Roth-Johnson (24:45):


Shira Shafir (24:45):

Um, the vaccine helps protect not only that individual, but the whole community. Um, and so it's definitely a good thing to get vaccinated. The, the other asterisk I want to put on there is—not having any side effects doesn't mean the vaccine didn't work. It just means you're darn lucky. Right. You've gotten the protection against the virus. And you didn't have to feel crummy for a few hours.

Perry Roth-Johnson (25:11):

Okay. Thanks for clearing that up.

Devin Waller (25:13):

Yeah! All right. One more. Uh, does the vaccine stay inside of our bodies for like a long period of time?

Shira Shafir (25:20):

Yeah, so the vaccine doesn't really stay in our bodies. Um, mRNA, which is in the Pfizer and the Moderna vaccines, is very fragile and it degrades very quickly. Um, so we get the vaccine, our body takes that mRNA instruction, makes the spike protein, um, and it's almost like disappearing ink. Then the mRNA degrades, and it's essentially gone. Um, the same thing, a little bit different of a mechanism, but, um, with the Johnson and Johnson adenovirus vector vaccine, it doesn't stay. Our body responds, controls it, um, and then it's essentially done and done.

Perry Roth-Johnson (25:57):

And Sihra, is there anything else you've been hearing often from folks? Or like, what things are you explaining over and over again when you talk to people like us?

Shira Shafir (26:05):

I get a lot of questions about whether or not the vaccine can change someone's DNA. Um, it cannot. It doesn't. The vaccines don't go anywhere near the nucleus of our cells, where our DNA is. Um, so it, it can't change our DNA. The other thing that I think is important is, is a lot of people say, "Well, I got COVID, I don't need to get a vaccine because I have natural immunity." Um, it is really important for people who, um, were infected with COVID and recovered to still get vaccinated, because we know that people develop a stronger and longer lasting immune response from the vaccine than they do from natural infection.

Devin Waller (26:44):

I've heard a variation of that question, which was, "I had COVID. If I get the first shot, did my COVID experience actually count as my second? So do I have to go back and get the follow-up shot?"

Shira Shafir (26:57):

So that's a great question. And scientists are actually trying to find the answer for that right now. Um, it's important right now, the Food and Drug Administration has approved Pfizer and Moderna have to be given in two doses, Johnson and Johnson has to be given in one dose. So for right now, even if someone had COVID and recovered, we still want them to complete the vaccine series, um, and, and make sure they're getting all of their shots.

Devin Waller (27:24):

Shira, here's a fun fact for you. Uh, the vaccines have their own hashtags on social media. So I just read an article—I was telling Perry this earlier—that I just read an article recently that listed #TeamPfizer and #ModernaGang are in competition for popularity. And so I thought it was the funniest thing, but I really, I love the awareness and it seems like a lot of people are talking about it.

Shira Shafir (27:49):

Yeah! You know, I think one of the most common questions now, when someone says, "Oh, I finally got vaxxed." The follow-up is, "Oh, what'd you get?"

Perry Roth-Johnson (27:58):


Devin Waller (27:58):


Shira Shafir (27:58):

You know, people ask me all the time, "Which vaccine should I get?" And my response is, "The first one that you're offered." You know, whatever someone has, um, that's going to be the best vaccine. But yes, obviously it's going to be the, the modern version of West Side Story. It's the Pfizers versus the Modernas versus the Johnson and Johnsons.

Perry Roth-Johnson (28:17):

Right, right.

Devin Waller (28:20):

So Shira, what else do you want people to know? Are there any other stories that you'd like to share or any sort of final notes that you want everybody to know?

Shira Shafir (28:29):

Probably the final thing is vaccines are safe. Vaccines are effective. They are nothing short of a scientific miracle. Um, and while we are achieving high levels of vaccination in the population, it's still going to be important to use those other public health prevention measures like masking and social distancing, particularly in indoor spaces. And, um, you know, hand hygiene was always a good idea. It will always be a good idea. So washing your hands well is, is never going to hurt anything.

Devin Waller (29:03):


Perry Roth-Johnson (29:05):

So Shira, where can people follow you online and find your work?

Shira Shafir (29:09):

Um, so they can follow me on Twitter, um, at, @IDPhD. Um, and if they're really interested in following my work, they can search for me on PubMed.

Perry Roth-Johnson (29:21):

There you go! Well, it's been wonderful talking to you, Shira. It's great to have an expert like you on our show. Thanks for joining us.

Shira Shafir (29:27):

Thank you so much. It's been a real pleasure.

Perry Roth-Johnson (29:29):

That's our show, and thanks for listening! Until next time, keep wondering. Ever Wonder? from the California Science Center is produced by me, Perry Roth-Johnson, along with Devin Waller. Liz Roth-Johnson is our editor. Theme music provided by Michael Nickolas and Pond5. We'll drop new episodes every other Wednesday. If you're a fan of the show, be sure to subscribe and leave us a rating or review on Apple Podcasts—it really helps other people discover our show. Have a question you've been wondering about? Send an email or voice recording to everwonder@californiasciencecenter.org, to tell us what you'd like to hear in future episodes.