VEC Vaccine Notes

Vaccine Education Center at Children’s Hospital of Philadelphia

Listen to “VEC Vaccine Notes,” a video and podcast series presented by the Vaccine Education Center at Children's Hospital of Philadelphia. Each episode offers vaccine information in a convenient format, so families have the answers they need to make informed decisions, including details and context that addresses what they may have heard in the news or in conversation with others. This podcast is for general informational and educational purposes only and is not to be considered as professional medical advice for your personal health or for your family's personal health. You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel. Clinicians must rely on their own informed clinical judgment in making recommendations to their patients. ©2026 The Children’s Hospital of Philadelphia.

  1. 4d ago

    Byproducts: Antibiotics - VEC Vaccine Notes | Vaccine Education Center at Children’s Hospital of Philadelphia

    Did you know that the first antibiotic, penicillin, was discovered by happenstance in the 1920s? Charlotte Moser, Co-Director of the Vaccine Education Center, touches briefly on this history as she discusses the use of antibiotics; health considerations, including allergic reactions and antibiotic resistance; and why antibiotics are used in vaccines. As she describes, any antibiotics that remain in vaccines are present in very small quantities, causing no harm. Find out more in this episode of VEC Vaccine Notes. Check out the video version on YouTube. Watch the episode to find out: How Alexander Fleming discovered the antibiotic properties of penicillin How World War II affected the development and availability of penicillin Some of the different considerations related to how antibiotics work Which types of antibiotics are used during the vaccine manufacturing process How many infections and deaths are caused by antibiotic resistance each year in the U.S. To learn more about antibiotics, please visit https://bit.ly/vec-antibiotics.  To learn more about vaccine ingredients, please visit https://bit.ly/vec-vax-ingredients. Questions? Submit the VEC Vaccine Notes form, https://bit.ly/contact-vec-vaccine-notes. For other vaccines, diseases or general questions about vaccines, check out https://vaccine.chop.edu/. Subscribe to our Parents PACK newsletter, https://bit.ly/3KfLUoO.

  2. Oct 7

    Byproducts: Formaldehyde - VEC Vaccine Notes | Vaccine Education Center at Children's Hospital of Philadelphia

    What is formaldehyde, and how much is present in vaccines? Find out in this episode of VEC Vaccine Notes. Charlotte Moser, Co-Director of the Vaccine Education Center, explains how our bodies naturally produce and break down formaldehyde every day — in quantities far exceeding those found in any vaccine. She talks about the differences between the gaseous and liquid forms of formaldehyde; the latter, called formalin, is the version used in vaccines. She also discusses where we encounter formaldehyde in daily life and why it remains in trace amounts as a purified byproduct in vaccines. This episode also explores the real-world health effects associated with long-term, high-dose occupational exposures, including cancers, and reveals why the minimal, infrequent exposure from childhood vaccines does not cause harm. Hint? A 2-month-old infant naturally has 10 to 220 times more formaldehyde circulating in their blood than what is delivered in any single vaccine. Check out the video version on YouTube. The different forms of formaldehyde What kinds of products and places it is found How much formaldehyde an infant can be exposed to from vaccines recommended during the first two years of life The situations when formaldehyde can cause health concerns To learn more about formaldehyde, please visit https://bit.ly/vec-formaldehyde. To learn more about vaccine ingredients, please visit https://bit.ly/vec-vax-ingredients. Questions? Submit the VEC Vaccine Notes form, https://bit.ly/contact-vec-vaccine-notes. For other vaccines, diseases or general questions about vaccines, check out https://vaccine.chop.edu/. Subscribe to our Parents PACK newsletter, https://bit.ly/3KfLUoO.

  3. Sep 30

    Preservatives: Thimerosal - VEC Vaccine Notes | Vaccine Education Center at Children’s Hospital of Philadelphia

    What is thimerosal, and why was it used as a vaccine preservative? Find out in this episode of VEC Vaccine Notes. Charlotte Moser, Co-Director of the Vaccine Education Center, explains the differences between elemental mercury (the silver-colored form of mercury found in products like thermometers and dental fillings), methylmercury (the type we’re exposed to when we eat fish), and ethylmercury (the preservative used in childhood vaccines). She details why small changes in the chemical structure between two compounds that might sound similar greatly impact the level of toxicity and how they are processed by our bodies. This episode also explores the history of thimerosal in multidose vials, why routinely recommended childhood vaccines in the United States transitioned to single-dose vials in the late 1990s, and what decades of rigorous scientific studies reveal about thimerosal and autism. Hint? Study after study found that thimerosal in vaccines does not cause autism. Check out the video version on YouTube. Listen to the episode to find out: About the worst, single-source mercury poisoning in history How ethanal and methanol can help us think about ethylmercury and methylmercury Symptoms of neurologic damage caused by mercury The different types of studies that looked at thimerosal exposure from vaccines Some of the known causes of autism and why we know mercury isn’t among them To learn more about thimerosal, please visit https://bit.ly/vec-thimerosal.  To learn more about vaccine ingredients, please visit https://bit.ly/vec-vax-ingredients. Questions? Submit the VEC Vaccine Notes form, https://bit.ly/contact-vec-vaccine-notes. For other vaccines, diseases or general questions about vaccines, check out https://vaccine.chop.edu. Subscribe to our Parents PACK newsletter, https://bit.ly/3KfLUoO.

  4. Sep 23

    Stabilizers: Gelatin and Polysorbate 80 & Vaccines - VEC Vaccine Notes | Vaccine Education Center at Children’s Hospital of Philadelphia

    Find out how gelatin and polysorbate 80 protect vaccines during manufacturing, storage and transport. Charlotte Moser, Co-Director of the Vaccine Education Center, also addresses common safety and cultural concerns related to these two vaccine ingredients, including severe allergic reactions, unfounded claims regarding polysorbate 80 and fertility, and religious guidelines surrounding porcine-derived gelatin. The discussion also includes a comparison of the amounts found in vaccines to exposures encountered in everyday foods and products and clarifies the health effects, safety and practical takeaways for considering both ingredients. Listen to the episode to find out: How gelatin is made The variety of products that contain gelatin and polysorbate 80 Which vaccine contains gelatin made from cows instead of pigs Three reasons religions that do not allow consumption of pig products still support use of vaccines that contain gelatin made from pigs The importance of the chemical structure of polysorbate 80 What micelles are Four types of evidence against the idea that polysorbate 80 causes fertility issues Check out the video version on YouTube. To learn more about gelatin, please visit https://bit.ly/vec-gelatin. To learn more about polysorbate 80, please visit https://bit.ly/polysorbate-80. Questions? Submit the VEC Vaccine Notes form, https://bit.ly/contact-vec-vaccine-notes. To learn more about vaccine ingredients, please visit https://bit.ly/vec-vax-ingredients. For other vaccines, diseases or general questions about vaccines, check out https://vaccine.chop.edu/. Subscribe to our Parents PACK newsletter, https://bit.ly/3KfLUoO.

  5. Sep 16

    Adjuvants: Aluminum & Vaccines - VEC Vaccine Notes | Vaccine Education Center at Children’s Hospital of Philadelphia

    What is aluminum, and why is it used in some vaccines? Find out in this episode of VEC Vaccine Notes. Charlotte Moser, Co-Director of the Vaccine Education Center, explains how aluminum adjuvants boost immune responses, where aluminum exists in our environment, and how quantities from vaccines compare to daily dietary exposure. This episode also covers how the body processes aluminum, why exposure has decreased over time due to combination vaccines, and what scientific evidence reveals about the safety of aluminum in vaccines. Check out the video version on YouTube. Listen to the episode to find out: Why we can’t avoid exposure to aluminum How much aluminum infants are estimated to consume in the first 6 months of life Why even though less than 1% of dietary aluminum reaches our bloodstream, what we eat still accounts for the majority of aluminum in our bodies How aluminum is processed and where it is stored in our bodies Which vaccines contain aluminum (and why live viral vaccines do not have aluminum) Two reasons aluminum exposure from infant vaccines has decreased over time When aluminum does cause health concerns About different studies evaluating the safety of aluminum in vaccines To learn more about aluminum, please visit https://bit.ly/vec-aluminum. To learn more about vaccine ingredients, please visit https://bit.ly/vec-vax-ingredients. Questions? Submit the VEC Vaccine Notes form, https://bit.ly/contact-vec-vaccine-notes. For other vaccines, diseases or general questions about vaccines, check out https://vaccine.chop.edu. Subscribe to our Parents PACK newsletter, https://bit.ly/3KfLUoO.

  6. Sep 9

    Types of Vaccine Ingredients - VEC Vaccine Notes | Vaccine Education Center at Children’s Hospital of Philadelphia

    Find out what ingredients are in vaccines, whether they’re safe, and how they are measured in this episode of VEC Vaccine Notes. Charlotte Moser, Co-Director of the Vaccine Education Center, breaks down the different types of ingredients in vaccines and why they are used. Guided by Paracelsus’ quote, "the dose makes the poison," this episode covers how relative quantities in vaccines (typically from nanograms to milligrams) compare with ingredient exposures in the context of daily life. Watch the episode to find out: Why avoiding any exposure to a particular vaccine ingredient can be difficult How to consider vaccine risks in the context of other exposures to vaccine ingredients How a raisin can help with estimating quantities The difference between weight-based quantities (like milligrams) and ratio-based quantities (like parts per million) The different types of antigens used in vaccines The three ways adjuvants can make vaccines work better and the five types currently used in the US The different roles of stabilizers and preservatives How manufacturing byproducts are like sand after a day at the beach Check out the video version on YouTube. To learn more about the different types of ingredients in vaccines and why they’re present, please visit https://bit.ly/vec-vax-ingredients.  Questions? Submit the VEC Vaccine Notes form, https://bit.ly/contact-vec-vaccine-notes. For other vaccines, diseases or general questions about vaccines, check out https://vaccine.chop.edu. Subscribe to our Parents PACK newsletter, https://bit.ly/3KfLUoO.

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Listen to “VEC Vaccine Notes,” a video and podcast series presented by the Vaccine Education Center at Children's Hospital of Philadelphia. Each episode offers vaccine information in a convenient format, so families have the answers they need to make informed decisions, including details and context that addresses what they may have heard in the news or in conversation with others. This podcast is for general informational and educational purposes only and is not to be considered as professional medical advice for your personal health or for your family's personal health. You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel. Clinicians must rely on their own informed clinical judgment in making recommendations to their patients. ©2026 The Children’s Hospital of Philadelphia.

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