Editorial note: This is part 3 of a three-part series evaluating the consequences of unfounded vaccine safety concerns. Part 1 discussed unfounded concerns about the safety of donated blood if someone received a COVID-19 vaccine and the real risks that people may not be aware of when they request directed blood donations. Part 2 considered the negative snowball effect as families increasingly refuse a common triad of newborn interventions, including hepatitis B vaccine, vitamin K shot, and erythromycin eye ointment.
When your water heater breaks and the repair person comes to fix it, they come with experience you don’t have. You don’t have experience with water heaters because most of the time, you aren’t thinking about them. You’re taking care of your kids, going to work, keeping a budget, and many other things.
Now, however, because your water heater is broken, you’re thinking more about them. You may try to do some online troubleshooting or ask your “network” who they would recommend for the repairs. You may price new ones and try to evaluate a few of the features, but even after this research, the repair person is still going to have a much deeper and more nuanced knowledge about water heaters. They spend every workday dealing with them. They know things like which brands hold up better, what problems can be fixed, which features are important and more.
Whether they fix your water heater or advise that it’s time to get a new one, at some level, you are paying them for their knowledge. Could you take care of this yourself? Maybe you could troubleshoot what’s happening, decide you need a new water heater, and pick one without hiring anyone. All may go well, and you’ll be set for another decade or so, but that will not be the outcome for everyone who goes the do-it-yourself (DIY) route. You might not hear about any of those failed attempts because most people only share good outcomes on their social media feeds, and they don’t typically talk about water heaters anyway. Chances are, however, your repair person could share a few stories since they hear about — and fix — some of the not-so-happy DIY endings.
So, what do broken water heaters have to do with vaccines? Not much actually, but like the water heater repair person, healthcare providers, and teams like ours, have a deeper and more nuanced body of information on which to draw when it comes to vaccines. We don’t see DIYers’ failed water heater attempts, but we do hear about the outcomes of decision-making related to vaccine safety concerns. In many cases, people delay or forgo vaccinations, and they don’t suffer any untoward consequences, but those aren’t the stories that we hear. And, sadly, if more people opt out because of the confusing messaging around vaccines, these kinds of stories will increase.
In part 3 of our series about the consequences of unfounded safety concerns, we want to focus on the nuance — information that is not always readily apparent when decisions are based on headlines, viral social media posts, or even some well-intended online research. As an example, we’re going to focus on two concerns that lead people to question vaccine safety and the nuanced interplay between these concerns when they become intertwined.
Concern 1: Too many vaccines
Concerns about too many vaccines tend to focus on the number of vaccines and the number of doses. Pictures of infants surrounded by syringes and various tallies of supposed doses of vaccines invariably invoke fear. However, these portrayals overlook several contextual points:
How the immune system works
Our hearts beat without us thinking about it. Our lungs move air without us thinking about it. And our immune systems defend against pathogens without us thinking about it. Our immune systems are 24/7 operations. So, the idea that the number of vaccines recommended during infancy could overwhelm the immune system lacks important understanding or consideration of this system designed to protect us from numerous daily challenges.
Number of vaccines versus number of antigens
Viral or bacterial proteins or complex sugars (so-called antigens) are contained in the vaccines to which the immune system responds.
- In the 1960s, the vaccines recommended against eight infectious diseases meant that infants received injections that contained around 3,200 antigens.
- By 2000, several new vaccines were available, so we could protect infants against 12 infectious diseases. These vaccines introduced only around 135 antigens. The large antigenic decrease, despite new vaccines, was caused by the shift from using the whole-cell pertussis vaccine (which contained about 3,000 antigens) to the acellular pertussis vaccine (which contains between 2 and 5 antigens).
- In 2026, those numbers have not changed much. Today, the number of antigens introduced in vaccines is between 158 and 171 — still well below the 3,200 antigenic exposures in the 1960s.
Two points are important here. First, the number of antigenic challenges presented by vaccines is small compared to what our immune systems handle daily. Second, the number of diseases children are protected against has been stable since 2000. Today’s young adults and parents likely had most of the vaccines recommended for their babies when they were younger.
Concern 2: Vaccine ingredients
A related concern is that other ingredients in vaccines are harmful, especially if the ingredient is in multiple vaccines. Aluminum is one such example. Not only are the amounts of aluminum questioned, but so, too, is the way the aluminum is introduced. Several contextual points are overlooked here as well:
Daily dietary exposures vs intermittent vaccine exposures
We eat, or ingest, aluminum every day. It’s estimated that adults consume between 7 and 9 mg of aluminum daily. Babies also consume aluminum as it is present in breast milk and formula. Because we ingest aluminum daily, and only about half of it is released from the body within 24 hours, we slowly accumulate aluminum from food over time.
Injection versus ingestion
When we ingest aluminum from food, less than 1% of it reaches our bloodstream. On the other hand, when it is injected in a vaccine, all that aluminum (100%) is in our bodies. This sounds scary, and it is often one of the points that people concerned about aluminum in vaccines make. However, the aluminum from a vaccine does not all reach the bloodstream at once after receipt of a vaccine. Rather, it stays near the site of injection where it is released slowly. This is part of why our immune systems make better immune responses to vaccines with adjuvants because the antigen is also released over time as the vaccine is processed.
Aluminum processing in our bodies
Finally, our bodies don’t “sort” aluminum based on its original source. Aluminum in the blood is processed the same way whether it is from our diet or vaccination. Likewise, we know that when a person’s kidneys aren’t working properly and they are exposed to ongoing large quantities of aluminum, negative health effects can occur. We also know what those effects look like. The amounts of aluminum from food and vaccines do not cause these effects.
Together, these understandings demonstrate that our bodies can manage aluminum regardless of how we are exposed to it, and the steady supply from our food presents a greater exposure than vaccines even though less aluminum is absorbed from ingestion compared with injection.
Trading known risks for unknown risks
In both cases — too many vaccines and vaccine ingredients — compelling and extensive data refute the concerns, which is why frontline healthcare providers and scientists continue to support existing vaccine recommendations. Despite this, some families worry about things they have heard. In response, some decide to delay or space out vaccines, thinking that this approach offers a safe compromise. That is, their child will still be protected, but “just in case” vaccines overwhelm the immune system, or the quantities of an ingredient are too high to be safe, they will protect their children against the possibility of harm while still vaccinating.
Unfortunately, this approach is where the nuance and depth of experience come into play. Parents wonder why healthcare providers don’t want to change the recommended schedule or work with them on a different schedule, and it’s because of that “water heater” knowledge — the knowledge you are paying for to ensure your child is safe and healthy. In this case, providers realize several things:
Single person data
Vaccines have been tested together to ensure they don’t interfere with immune responses, so an individualized approach disregards existing data on the immune system effects of these vaccines being given together. While the child may not experience negative consequences, this approach is antithetical to concerns about a lack of data supporting the existing schedule.
Increased ingredient exposures
When vaccines are spaced out, the opportunity to use combination vaccines decreases. This may seem like it aligns with the concerns about too many vaccines, but depending on which single vaccines are used, the child could end up with larger exposures to some of the ingredients of concern, such as aluminum.
For example, the vaccines recommended at 2 months of age include hepatitis B, DTaP, Haemophilus influenzae type b (Hib) and pneumococcal. If given individually, using the brand with the most aluminum, these infants would receive about 1.1 mg of aluminum. However, if the child receives combination vaccines, they could be exposed to one-third to one-half the amount of aluminum. While even the largest quantities of aluminum have been shown not to be harmful, this example demonstrates that some decisions simply change one theoretical risk (too many vaccines) for another (quantities of ingredients).
Longer period of risk
During the time it takes to complete the delayed doses, the child will remain unnecessarily vulnerable. As vaccine-preventable diseases continue to circulate, and in some cases increase in number of outbreaks, this extended vulnerability could mean experiencing a life-altering infection. Remember, healthcare providers know what’s circulating because they are seeing it even if it hasn’t been in the headlines or on social media.
Takeaway: Of water heaters and vaccines
Whether deciding on a new water heater or a vaccination, we all try to do what’s best for our families. We want to keep them safe, healthy and comfortable. And, whether the water heater or the vaccine, we can find information online or talk to family and friends to help inform our decision. But, in both cases, if we decide against checking with those who have experience in the form of the repair person or healthcare provider, we may fail to consider consequential information. While many will never be the wiser because everything will work out, that won’t be the case for all. Some will regret their water heater decision, and some will regret their vaccine (or other health) decision. Sadly, the regrets of one of these groups is likely to be much more consequential.
Series wrap-up
We hope our exploration of some of the less obvious outcomes of unfounded vaccine safety concerns was both interesting and enlightening. People make health decisions throughout their lives, and it’s their right to make the decisions that are best for them. However, if they don’t have all the information and use all the resources at their disposal — including their healthcare providers — they may be making decisions that can increase their suffering or worse. Healthcare decisions are too personal and important to survey our social networks or become a crusade.
Resources
Vaccine schedule
- Science Behind the Vaccine Schedule (webpage)
- Vaccine Schedule: Altering the Schedule (webpage)
Aluminum
- Vaccine Ingredients: Aluminum (webpage)
- Aluminum in Vaccines: Is it Safe? (video)
Editorial note: This is part 3 of a three-part series evaluating the consequences of unfounded vaccine safety concerns. Part 1 discussed unfounded concerns about the safety of donated blood if someone received a COVID-19 vaccine and the real risks that people may not be aware of when they request directed blood donations. Part 2 considered the negative snowball effect as families increasingly refuse a common triad of newborn interventions, including hepatitis B vaccine, vitamin K shot, and erythromycin eye ointment.
When your water heater breaks and the repair person comes to fix it, they come with experience you don’t have. You don’t have experience with water heaters because most of the time, you aren’t thinking about them. You’re taking care of your kids, going to work, keeping a budget, and many other things.
Now, however, because your water heater is broken, you’re thinking more about them. You may try to do some online troubleshooting or ask your “network” who they would recommend for the repairs. You may price new ones and try to evaluate a few of the features, but even after this research, the repair person is still going to have a much deeper and more nuanced knowledge about water heaters. They spend every workday dealing with them. They know things like which brands hold up better, what problems can be fixed, which features are important and more.
Whether they fix your water heater or advise that it’s time to get a new one, at some level, you are paying them for their knowledge. Could you take care of this yourself? Maybe you could troubleshoot what’s happening, decide you need a new water heater, and pick one without hiring anyone. All may go well, and you’ll be set for another decade or so, but that will not be the outcome for everyone who goes the do-it-yourself (DIY) route. You might not hear about any of those failed attempts because most people only share good outcomes on their social media feeds, and they don’t typically talk about water heaters anyway. Chances are, however, your repair person could share a few stories since they hear about — and fix — some of the not-so-happy DIY endings.
So, what do broken water heaters have to do with vaccines? Not much actually, but like the water heater repair person, healthcare providers, and teams like ours, have a deeper and more nuanced body of information on which to draw when it comes to vaccines. We don’t see DIYers’ failed water heater attempts, but we do hear about the outcomes of decision-making related to vaccine safety concerns. In many cases, people delay or forgo vaccinations, and they don’t suffer any untoward consequences, but those aren’t the stories that we hear. And, sadly, if more people opt out because of the confusing messaging around vaccines, these kinds of stories will increase.
In part 3 of our series about the consequences of unfounded safety concerns, we want to focus on the nuance — information that is not always readily apparent when decisions are based on headlines, viral social media posts, or even some well-intended online research. As an example, we’re going to focus on two concerns that lead people to question vaccine safety and the nuanced interplay between these concerns when they become intertwined.
Concern 1: Too many vaccines
Concerns about too many vaccines tend to focus on the number of vaccines and the number of doses. Pictures of infants surrounded by syringes and various tallies of supposed doses of vaccines invariably invoke fear. However, these portrayals overlook several contextual points:
How the immune system works
Our hearts beat without us thinking about it. Our lungs move air without us thinking about it. And our immune systems defend against pathogens without us thinking about it. Our immune systems are 24/7 operations. So, the idea that the number of vaccines recommended during infancy could overwhelm the immune system lacks important understanding or consideration of this system designed to protect us from numerous daily challenges.
Number of vaccines versus number of antigens
Viral or bacterial proteins or complex sugars (so-called antigens) are contained in the vaccines to which the immune system responds.
- In the 1960s, the vaccines recommended against eight infectious diseases meant that infants received injections that contained around 3,200 antigens.
- By 2000, several new vaccines were available, so we could protect infants against 12 infectious diseases. These vaccines introduced only around 135 antigens. The large antigenic decrease, despite new vaccines, was caused by the shift from using the whole-cell pertussis vaccine (which contained about 3,000 antigens) to the acellular pertussis vaccine (which contains between 2 and 5 antigens).
- In 2026, those numbers have not changed much. Today, the number of antigens introduced in vaccines is between 158 and 171 — still well below the 3,200 antigenic exposures in the 1960s.
Two points are important here. First, the number of antigenic challenges presented by vaccines is small compared to what our immune systems handle daily. Second, the number of diseases children are protected against has been stable since 2000. Today’s young adults and parents likely had most of the vaccines recommended for their babies when they were younger.
Concern 2: Vaccine ingredients
A related concern is that other ingredients in vaccines are harmful, especially if the ingredient is in multiple vaccines. Aluminum is one such example. Not only are the amounts of aluminum questioned, but so, too, is the way the aluminum is introduced. Several contextual points are overlooked here as well:
Daily dietary exposures vs intermittent vaccine exposures
We eat, or ingest, aluminum every day. It’s estimated that adults consume between 7 and 9 mg of aluminum daily. Babies also consume aluminum as it is present in breast milk and formula. Because we ingest aluminum daily, and only about half of it is released from the body within 24 hours, we slowly accumulate aluminum from food over time.
Injection versus ingestion
When we ingest aluminum from food, less than 1% of it reaches our bloodstream. On the other hand, when it is injected in a vaccine, all that aluminum (100%) is in our bodies. This sounds scary, and it is often one of the points that people concerned about aluminum in vaccines make. However, the aluminum from a vaccine does not all reach the bloodstream at once after receipt of a vaccine. Rather, it stays near the site of injection where it is released slowly. This is part of why our immune systems make better immune responses to vaccines with adjuvants because the antigen is also released over time as the vaccine is processed.
Aluminum processing in our bodies
Finally, our bodies don’t “sort” aluminum based on its original source. Aluminum in the blood is processed the same way whether it is from our diet or vaccination. Likewise, we know that when a person’s kidneys aren’t working properly and they are exposed to ongoing large quantities of aluminum, negative health effects can occur. We also know what those effects look like. The amounts of aluminum from food and vaccines do not cause these effects.
Together, these understandings demonstrate that our bodies can manage aluminum regardless of how we are exposed to it, and the steady supply from our food presents a greater exposure than vaccines even though less aluminum is absorbed from ingestion compared with injection.
Trading known risks for unknown risks
In both cases — too many vaccines and vaccine ingredients — compelling and extensive data refute the concerns, which is why frontline healthcare providers and scientists continue to support existing vaccine recommendations. Despite this, some families worry about things they have heard. In response, some decide to delay or space out vaccines, thinking that this approach offers a safe compromise. That is, their child will still be protected, but “just in case” vaccines overwhelm the immune system, or the quantities of an ingredient are too high to be safe, they will protect their children against the possibility of harm while still vaccinating.
Unfortunately, this approach is where the nuance and depth of experience come into play. Parents wonder why healthcare providers don’t want to change the recommended schedule or work with them on a different schedule, and it’s because of that “water heater” knowledge — the knowledge you are paying for to ensure your child is safe and healthy. In this case, providers realize several things:
Single person data
Vaccines have been tested together to ensure they don’t interfere with immune responses, so an individualized approach disregards existing data on the immune system effects of these vaccines being given together. While the child may not experience negative consequences, this approach is antithetical to concerns about a lack of data supporting the existing schedule.
Increased ingredient exposures
When vaccines are spaced out, the opportunity to use combination vaccines decreases. This may seem like it aligns with the concerns about too many vaccines, but depending on which single vaccines are used, the child could end up with larger exposures to some of the ingredients of concern, such as aluminum.
For example, the vaccines recommended at 2 months of age include hepatitis B, DTaP, Haemophilus influenzae type b (Hib) and pneumococcal. If given individually, using the brand with the most aluminum, these infants would receive about 1.1 mg of aluminum. However, if the child receives combination vaccines, they could be exposed to one-third to one-half the amount of aluminum. While even the largest quantities of aluminum have been shown not to be harmful, this example demonstrates that some decisions simply change one theoretical risk (too many vaccines) for another (quantities of ingredients).
Longer period of risk
During the time it takes to complete the delayed doses, the child will remain unnecessarily vulnerable. As vaccine-preventable diseases continue to circulate, and in some cases increase in number of outbreaks, this extended vulnerability could mean experiencing a life-altering infection. Remember, healthcare providers know what’s circulating because they are seeing it even if it hasn’t been in the headlines or on social media.
Takeaway: Of water heaters and vaccines
Whether deciding on a new water heater or a vaccination, we all try to do what’s best for our families. We want to keep them safe, healthy and comfortable. And, whether the water heater or the vaccine, we can find information online or talk to family and friends to help inform our decision. But, in both cases, if we decide against checking with those who have experience in the form of the repair person or healthcare provider, we may fail to consider consequential information. While many will never be the wiser because everything will work out, that won’t be the case for all. Some will regret their water heater decision, and some will regret their vaccine (or other health) decision. Sadly, the regrets of one of these groups is likely to be much more consequential.
Series wrap-up
We hope our exploration of some of the less obvious outcomes of unfounded vaccine safety concerns was both interesting and enlightening. People make health decisions throughout their lives, and it’s their right to make the decisions that are best for them. However, if they don’t have all the information and use all the resources at their disposal — including their healthcare providers — they may be making decisions that can increase their suffering or worse. Healthcare decisions are too personal and important to survey our social networks or become a crusade.
Resources
Vaccine schedule
- Science Behind the Vaccine Schedule (webpage)
- Vaccine Schedule: Altering the Schedule (webpage)
Aluminum
- Vaccine Ingredients: Aluminum (webpage)
- Aluminum in Vaccines: Is it Safe? (video)