Prakash Chandran (Host): Vaccines don't have to be as scary as the needles we use to inject them. In fact, immunization has been saving lives and preventing disease for decades. But how exactly do vaccines work, how effective are they and what are the potential risks?

Host: Here with us to discuss is Dr. Gerica Alvarado and Dr. Gaurav Zirath, family physicians and core faculty with the Valley Health System's Family Medicine Residency Program.

 Welcome to Health Talk with the Valley Health System, presented by the Valley. I'm your host, Prakash Chandran. So Dr. Alvarado and Dr. Zirath, thank you so much for joining me today. Dr. Zirath, I thought I would start with you just asking a basic question. How exactly does immunization work to prevent disease?

Dr. Gaurav Zirath: The vaccines and immunization, they're very unique on how they work. Vaccines, once you receive them, what it does is it creates an imitation infection, which is not a real infection. It's just a very, very minor form of the actual infection. What this imitation infection does is that it teaches the immune system on how to fight off a future infection. So once you are vaccinated, the body has immune cells such as T lymphocytes and B lymphocytes. Once they have gone through this initial imitation infection, they remember how to fight off an actual infection when someone is exposed to the actual pathogen. Once you receive a vaccine, sometimes you may experience some very minor symptoms such as fever. These minor symptoms are very common as the body's building immunity, and these symptoms are very self-limiting.

Dr. Gerica Alvarado: And I'd also like to add that it doesn't necessarily mean that you are 100% prevented from getting the disease. It might just be that the vaccine is designed to make symptoms milder or shorten the time of symptoms. So, some vaccines decrease death or hospitalization. So even though you might still get the disease, it's a very, very mild form of the disease because as Dr. Zirath was saying, your immune system is ready and primed and ready to fight the infection after getting vaccinated.

Host: So Dr. Alvarado, I think many of us are aware of the most recent COVID-19 vaccine. But obviously, there are immunizations that people get throughout their lifetime. Can you tell us what those are?

Dr. Gerica Alvarado: Of course. So, all of us as children get the childhood immunizations, or all of us should get those childhood immunizations as children. And then throughout your lifetime, the two most common vaccines that we'll get are the flu vaccine, which is recommended that we get it annually, starting at the age of six months, but also the TDAP vaccine, which we get several of them throughout childhood. But it's recommended that we repeat that TD, that tetanus piece of it, every 10 years. And also with that TDAP vaccine, it's recommended that we get it in pregnancy, during every pregnancy. So even if you've recently been vaccinated with the TDAP and you get pregnant three years in a row, we recommend it. You get it every pregnancy. And that's not to protect you, but that's for that passive immunity to be passed on to baby, specifically for pertussis or whooping cough.

Host: So Dr. Zirath, I want to move on to efficacy. You know, Dr. Alvarado covered some of the immunizations that we get throughout our lifetime. And I know one of the things that was mentioned was, you know, it's not a full proof immunization when you get vaccines, but could you talk a little bit about how efficacy is measured.

Dr. Gaurav Zirath: Absolutely. The vaccines are actually very, very effective in preventing infections and also reducing the severity of the infection if someone does get infected despite being vaccinated. But Dr. Alvarado mentioned earlier today that not all vaccines are hundred percent effective. Some people may experience infections even though they may have already been vaccinated against a particular pathogen. However, what the vaccine does is that, in case if you do develop the infection despite the immunization, your infection course may not be or should not be as severe as it may have been if you were not vaccinated.

And how do we measure effectiveness of the vaccine? So prior to the vaccines getting released to the general public, there are controlled clinical trials that are done at quite large capacity to determine if they're effective or not. And just to give some examples on how effective the vaccines are, again, two things that come to mind is smallpox that had killed a lot of people back into the early 1900s and late 1900s. And smallpox vaccine, once it came out, it actually eradicated the infection, I think in the 1970s. And same thing with measles. You know, measles was also affecting a lot of younger children before the vaccines were around. And once the vaccine program was released we were able to eradicate measles as well from our communities.

And the other way we can actually measure effectiveness or if the vaccines are working or not in the body is by checking titers. So if someone needs to know or wants to know perhaps to see if a vaccine has worked, for certain immunizations for hepatitis, for example, varicella, MMR, we can actually check your titers from a quick blood test and know if your body has built immunity.

Dr. Gerica Alvarado: I'd like to quickly put in a plug for the HPV vaccine in particular. So, we've mentioned a few times that nothing is a hundred percent. I wish we had vaccines that were a hundred percent, but the HPV vaccine is pretty close. It is 98% effective in preventing HPV. And this is really fantastic because HPV is a virus that causes cancers, causes rectal cancers, vaginal cancers, cervical cancers, esophageal cancers. And so if we can prevent this virus, we can actually prevent cancer. So, I recommend everyone be vaccinated with the HPV vaccine, both men and women because, like I said, it's pretty, pretty effective.

Dr. Gaurav Zirath: Thank you, Dr. Alvarado, for putting in that plug. I think that's very important, not only from an infection standpoint, but also from cancer prevention. And to go along the same lines, in order for the vaccines to be effective, it is very important that we get all the shots in the series. Some vaccines may have a two-dose C or three doses, so it's important for everyone to understand that, to get the best effectiveness, we have to make sure we complete the entire series of shots.

Host: So Dr. Alvarado, I think that we've covered a lot of the different immunizations that people get. But I think at a high level, people might not necessarily understand how vaccines get created. You know, we've heard about the emergency use authorization to expedite that development or maybe the distribution of the COVID-19 vaccine. But for the most part, I hear that it's actually quite a rigorous cycle for a vaccine to get released. So, Dr. Alvarado, could you speak to that at a high level?

Dr. Gerica Alvarado: It is a lengthy, lengthy process to get a vaccine out there to the general public. So, there are multiple levels, multiple trials. The first thing that has to happen is we have to figure out which part of the virus or the bacteria our body is reacting to. So, there are actual proteins on the walls of viruses or bacteria that your body forms immunity to, and we have to figure out which one of those is actually going to be the most effective in eradicating the illness when it comes into contact with the body. So even though there may be 20 different proteins on this particular antigen, we have to figure out which one is going to work the best. So, that's the first piece of it.

Once we figured it out, then we have to figure out how can it be delivered to the body in order to create that desired effect, right? Just because we put it into a nice little syringe and give it to someone doesn't mean that the immune system is going to do what we want it to do. So, there's lots of other things that go into the vaccine. There's lots of other ingredients, preservatives, immune response boosters that have to be formulated into the vaccine for them to do what we want them to do and do it safely.

And then, safety is a huge component of vaccine development. So, there are pre-human trials. So, there's everything from test tubes to animals before we ever get to the human trials. And then, there's several stages of human trials before we ever bring it out to the general population.

Dr. Gaurav Zirath: And to add to that, you know, even after the clinical trials are over and the vaccine is currently being used for public use, there's the different organizations, CDC, for example, or World Health Organizations and several other government entities actually track the efficacy, the side effects, everything, even after the vaccine has been rolled out. So, it doesn't mean that once the vaccine has been rolled out, no one's monitoring it. There's actually quite a bit of data that's collected for the vaccines being given out after it's made public.

Dr. Gerica Alvarado: That's right. Every single adverse event is reported, so that we can look for patterns and respond quickly if we notice that there is some associated risk with a particular vaccine or a particular vaccine combination. So, a lot of the childhood vaccines are given in combination, meaning there are three or four different vaccines being delivered in one shot or several shots being given at every visit. Those particular combinations have also been tested to ensure they are safe to give at the same time.

Host: Yeah. So obviously, the testing regimen around, you know, approving or getting these vaccines approved is quite rigorous and very comprehensive. I do wonder, Dr. Zirath, just around potential risks associated with, you know, getting a vaccine or getting immunization, I think this is something that people worry about. So, outside of the minor symptoms that you mentioned, when you receive a vaccine, can you talk a little bit about risks and how you work to minimize them?

Dr. Gaurav Zirath: Absolutely. So, you mentioned, you know, very common side effects that one may experience after getting a vaccine, which may include, you know, pain, swelling, redness around the site where you receive the vaccine, mild fevers, chills, tiredness, headaches, muscle and joint aches, what have you. Those are very common side effects and very self-limiting. They may last at one to two days, maybe a few days.

But some of the serious side effects to discuss, which again, are very, very rare, I did come across a statistics that was quoted by US Department of Health and Human Services. They mentioned that if 1 million doses of vaccine are given, only about one to two people may experience a severe allergic reaction. And that severe allergic reaction maybe in the form of difficulty breathing, face and throat swelling, fast heart rate, all-body rash, feeling dizzy, feeling weak, things of that sort. So if someone does experience those, again, next best thing to do is to call 911 and letting your clinician know that you have experienced these symptoms in the past so that the future vaccines, when they're administered, they can be administered with caution. Again, the prevalence of these serious illnesses are very, very, very, very low.

Dr. Gerica Alvarado: Other serious side effects that we may be more familiar with following the COVID vaccine, these are things like GBS or Guillain-Barré syndrome. This can happen after any infection, so it can happen after a viral infection or a bacterial infection. It's an overreaction of your immune system where it starts to attack the nervous system. And so, yes, it is true that this is one of those rare reactions after immunization, but it is more likely to come after a disease, not after an immunization.

Something else that happens specifically in childhood are febrile seizures, which again can happen with any fever. And because vaccines can cause fevers as they are gearing up that immune system response, it can lead to febrile seizures. Now, febrile seizures, as scary as they can be, have no long-term consequences for children. No lasting effects.

Host: So Dr. Alvarado, how do vaccine-preventable diseases affect vulnerable populations, you know, such as children, the elderly, and those who might have weakened immune systems?

Dr. Gerica Alvarado: Yes, absolutely. So, not everyone can get vaccinated. Especially younger children, infants, they can't get every single vaccine at the same time, meaning that they are at higher risk of disease and at higher risk for more serious effects of the disease. So, things like we mentioned measles, but also something like the flu. So, most children cannot be vaccinated before the age of six months. And so, it's important for those around the child to be vaccinated, so that they can protect the child. Same with people with autoimmune diseases, things like HIV or certain rheumatologic diseases, they cannot get every single vaccine. But if the community is vaccinated, we can help protect those. This is something that most of you have probably heard as herd immunity. Now, it's not perfect. Again, nothing is a hundred percent. But if those people who are at higher vulnerability are surrounded by people who are protected, then they're more likely to be protected.

Host: So, Dr. Zirath, I do now want to get into some of the common myths or misconceptions about immunization. Just to name a few, I know I've heard about the autism claim about vaccines, just you know, what they can do to potentially a woman that is pregnant. There's a lot of different ones that are floating around. So, I was hoping that you might address some of the more popular ones that you've heard and just address if they have any merit.

Dr. Gaurav Zirath: Absolutely. Thank you for asking that question. So, talking about autism, vaccines do not cause autism. And if you look at the data, there's been substantial amounts of data that's been published, not just in the United States, but all around the world that state that the vaccines do not cause autism. And in fact, some of the studies have looked at the individual ingredients that the vaccines are made of, and even the ingredients do not cause any autism. So, you know, children vaccines are very, very important and to make sure that, if you have any concerns about autism, speak to your clinician, and I'm sure they will also reassure you that vaccines are not known to cause autism.

And some of the other myths I've heard is do the vaccine cause actual infection? You know, I personally heard that myself from friends, family members as well, where things like getting a flu vaccine will actually give me the flu, which is absolutely not true. Again, what we mentioned earlier is that some minor side effects such as, you know, feeling fever, having chills, body aches and what have you, those are very common and those are not signs of an actual infection. That's just your body building immunity. So, the vaccine themselves do not cause the actual disease. That's the other myth that we've heard. And Dr. Alvarado will certainly go into some of the ingredients and how they play a role into the vaccines.

Dr. Gerica Alvarado: Yeah. So, I mentioned before when we talked a little about how vaccines are made, is that there's other ingredients that go into the vaccine in order to help preserve things or boost our immune response. Some of the ingredients that seem to be the most concerning that I've seen a lot of fear surrounding them are things like formaldehyde, aluminum, they just sound scary, right?

Formaldehyde, we think about it being this preservative. But formaldehyde is an organic compound. It is naturally occurring. It is found in a lot of things we eat. It's placed in the vaccine to help inactivate some of these antigens so that they are not causing severe reactions. And just to put it into perspective, one banana has five times the amount of formaldehyde that we find in the entire childhood vaccine schedule. So, it is a minuscule amount.

Then, there's things like thimerosal, which we had concerns about before. It was one of the compounds that was thought to be tied to autism. Given the amount of concern surrounding that particular ingredient, it's actually been taken out of a lot of vaccines. So right now, it's only found in multi-dose vials of the flu, nothing else. So, all of the childhood vaccines are free of thimerosal.

Lastly, there's aluminum. Aluminum is placed in vaccines to boost the immune response. It has no adverse effects and it's actually found in things like infant formula, so we know it's very, very safe.

Host: So just as we close, there's a question that I'd like to ask both of you. And Dr. Alvarado, we'll start with you. You know, just given all of the work that you've done with vaccines and just, you know, seeing patients that have gotten them over time, what is one thing that you know to be true that you wish more people knew or you just want to leave with our audience?

Dr. Gerica Alvarado: So, I think it is normal to be concerned. It is normal to be weary. It is normal to be skeptical. I want my patients to be informed. I want them to feel like they are in charge of their health. And I am not annoyed when you have questions about vaccines or when you want to think about it or when you bring an article. I am happy to talk about it. I learn so much from my patients, and I never want you to feel dismissed by your physicians when you bring up these concerns. And so, I know vaccines are safe. But I want you to feel like what I am recommending to you is right for you and safe for you. So, it's okay, ask questions.

Host: Yeah, I think that's perfect. Thank you so much for sharing, Dr. Alvarado. Dr. Zirath, same question to you. I'll give you the last word.

Dr. Gaurav Zirath: Thank you and thank you, Dr. Alvarado, for mentioning that. I totally agree. Patients that have concerns relating to vaccines a lot of times may feel intimidated or perhaps scared to come into the doctor's office, and that's absolutely not true. We all encourage questions surrounding vaccines and how effective they are, any side effects, things like that. Again, please don't feel scared, don't feel intimidated. We are here to answer any questions you might have. A lot of times I agree with Dr. Alvarado, I learn so much from our patients and the questions they ask.

In closing remarks, I do want to mention that the vaccines are effective and they save lives, especially in the younger children and the elderly population. So if you have younger children and if you have elderly parents that may be immunocompromised, please get them vaccinated after talking to their clinician. And this is all done to make sure that we save their lives and make sure they're as safe as they can be out in the community.

Host: Well, Dr. Zirath and Dr. Alvarado, I think that is the perfect place to end. Thank you both so much for your time.

Dr. Gaurav Zirath: Thank you.

Dr. Gerica Alvarado: Thank you for having us.

Host: That was Dr. Gerica Alvarado and Dr. Gaurav Zirath, family physicians and core faculty with the Valley Health System's Family Medicine Residency Program. For more information, you can visit us at valleyhealthsystemlv.com. If you found this podcast to be helpful, please share it on your social channels and be sure to check out the entire podcast library for topics of interest to you.

Thanks for checking out this episode of Health Talk with the Valley Health System, presented by the Valley. My name is Prakash Chandran. Stay well.

Physicians are independent practitioners who are not employees or agents of the Valley Health System. The system shall not be liable for actions or treatments provided by physicians.