Editorial note: This is part 2 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 3 will be published in July 2026 and consider the importance of nuanced understanding that comes from experience.
We’ve all been there. We’re starting something new — a project, an idea, a snowman … wait, what? When we make a snowman, we start with a handful of snow and then roll it around the yard, so it gets bigger and bigger. We apply that concept to other projects or ideas using the term “snowball effect.” We start small and hope our project or idea “snowballs.” You may have also heard of it as a way of getting out of debt — pay off your smallest outstanding source of debt while paying the minimum on other debt. Once the smallest one is paid off, add that amount to the minimum you’ve been paying on your next smallest amount. Do this over and over, increasing the amount you put toward the larger debts each time.
Unfortunately, the snowball effect can work in the opposite way as well, causing increasing amounts of damage — think of terms like “gateway drugs,” “snowball betting” or “Ponzi scheme.” In each case, the entry point is small, but over time, the damage accrues. The negative snowball effect is what we are also starting to see when it comes to unfounded vaccine safety concerns. As the newborn hepatitis B vaccine dose has come under fire, parents are not only opting out of protecting their newborns against this infection, they’re also refusing other lifesaving, decades-old interventions.
Immediate effects: Hepatitis B vaccine
In December 2025, a group of advisors to the Centers for Disease Control and Prevention (CDC) changed a vaccine recommendation that had been in place for more than 30 years. From 1991 until 2025, all babies were recommended to get the hepatitis B vaccine within 12 hours of birth (see image). This strategy virtually eliminated chronic hepatitis B disease in children and young adults. However, the advisors disregarded established science and decades of experience to return to a practice that was tried and didn’t work prior to 1991 — that is to vaccinate only infants of hepatitis B-positive mothers. In making their decision, this advisory group did not just change course in the absence of new evidence, they disregarded decades of existing real-world experience showing that the current recommendation was superior.
Unfortunately, we are already hearing about the effects of this change:
Increased numbers of refusals
Increasing numbers of parents are refusing or delaying the hepatitis B vaccine at birth. While the risk for exposure to hepatitis B in the first year of life is low, it still happens. Further, infection in the first year of life is most likely to result in chronic liver disease (called cirrhosis) or liver cancer, as shown by these age-based risks of developing these life-limiting conditions (see resources at end of article):
- 90 of 100 babies exposed in the first year of life
- 30 of 100 children exposed between 1 and 4 years of age
- 5 of 100 adults following exposure
Refusals even among hepatitis B-positive mothers
Even though the change was made to vaccine recommendations in situations where the mother tests negative for hepatitis B prior to delivery, the effects are being realized beyond this group. Frontline healthcare providers are reporting increased patterns of refusal among families where the mother is known to have hepatitis B. When a woman is positive for hepatitis B, she can pass it to her baby:
- During the birthing process — About 70-90 of 100 babies born to women who test positive will be infected. Without treatment, most of them will develop chronic hepatitis B themselves. However, with receipt of both antibodies and vaccination at birth, only 5 to 15 of 100 infected babies will develop a chronic infection.
- During early childhood — Given that infants born to hepatitis B-positive mothers remain at risk throughout early childhood because of ongoing exposure to the virus in the home, vaccination benefits babies of hepatitis B-positive mothers beyond the birth exposure. Data demonstrate that with vaccination at birth, almost all of these babies are protected.
The snowball effect: Hepatitis B newborn dose and the future
Numerous other considerations are relevant for protecting babies from hepatitis B:
Imperfect systems
Some tests are falsely negative, and about 14 of every 100 pregnant women are never tested before delivery. Even with testing, sometimes results are not received in time, the birth occurs outside of a hospital setting, or the testing and delivery occur in different healthcare systems, making it difficult to access the results. In short, the system is not perfect, so some babies will be missed.
Unknown infections
About half of all chronically infected people in the U.S. do not actually know they have a chronic hepatitis B infection. They won’t find out until they develop liver disease or liver cancer. In the meantime, they can — and do — unwittingly infect other people. Before universal birth dose vaccination, each year about half of the children diagnosed with hepatitis B were infected by someone other than their mother. Often, they never knew where or by whom they were infected.
The universal recommendation reduced hepatitis B infections in children and young adults by 99%. If this recommendation to delay vaccination is followed, we will see those rates rise, which means over time there will be even more people who become chronically infected and spread the disease — the negative snowball effect.
Learning from history
Existing historical data have also established that infants who receive the birth dose of hepatitis B vaccine are more likely to get all of the recommended doses of that vaccine as well as their other childhood vaccines. This, too, will lead to accumulating infections — not only of hepatitis B but possibly also other vaccine-preventable infections. Yet again, the negative snowball effect grows.
Predicting the future
Modeling studies are studies using data that we have available to predict what will happen in different situations. These studies are not perfect because they are trying to predict what might happen, and assumptions that are made could change, causing the models to be inaccurate. However, modeling studies can still be useful for understanding the realm of possibilities.
A recent modeling study of a single U.S. birth cohort (3.6 million infants) evaluated delaying the hepatitis B vaccine birth dose to 2 months for infants with mothers who do not have hepatitis B (as recommended in December 2025 by the CDC committee) or to 12 years (as suggested by the U.S. President). The study predicted:
- If the vaccine is given at 2 months of age to children whose mothers do not have hepatitis B: 20-40 additional cases of liver cancer and 30-60 additional deaths would occur, depending on how well the vaccine recommendations are followed.
- If vaccination is delayed until 12 years of age: About 500 additional cases of liver cancer and almost 800 additional deaths would occur.
Remember that, in both scenarios, each of these are completely unnecessary cancers and deaths because we have a vaccine that works, and changing the recommendation did not do anything to improve safety.
The study also suggested the costs of treating these additional cases would be between $16 million and $22 million if the vaccine is started at 2 months of age and $313 million to $368 million if delayed until 12 years of age. Likewise, the CDC committee suggested screening children after the first dose before getting additional doses, which would increase these costs to $119 million to $123 million at 2 months of age and $409 million to $471 million at 12 years of age. Further, the additional doses are necessary for long-term protection, so we could start to see people who only got one dose become susceptible later in life — adding to the negative outcomes snowball we are building with this change.
The snowball effect: Other newborn protections
Another example of the negative snowball effect is that parents of newborns are also becoming increasingly comfortable refusing other established newborn protections, such as the vitamin K shot and erythromycin eye ointment.
Vitamin K
Babies are born with low levels of vitamin K, making them more prone to prolonged and internal bleeding. (Vitamin K is not transferred to the baby through the placenta nor is it transmitted to the baby through breast milk.) For example, vitamin K deficiency can cause bleeding in the brain that can result in death or long-term neurological damage. Rates are higher in the first hours and days after birth, but the deficiency lingers throughout the first months of life until babies start eating table food. Since the early 1960s, infants have been receiving a single shot of vitamin K shortly after birth, which provides a sufficient supply of the vitamin to protect them throughout the vulnerable first months of life. As increasing numbers of families opt out of this shot for their babies, preventable cases of bleeding and death will increase. Sadly, we have already heard of brain bleeds and deaths following parental refusal of the vitamin K shot.
Erythromycin eye ointment
Infants are exposed to several types of bacteria as they come through the birth canal. Sometimes, the bacteria get in the baby’s eyes, causing pinkeye. One of the most concerning types are the bacteria that cause gonorrhea, called Neisseria gonorrhoeae, as an infection can cause scarring of the cornea and permanent blindness. For this reason, babies are recommended to get erythromycin eye ointment in the first few hours after birth. Many parents hear that the cause is gonorrhea and decide their infant does not require this treatment because they self-assess that they could not have the sexually transmitted infection (STI). However, the bacteria are not always detected in prenatal testing, and more recently the rates of gonorrhea have been increasing among women of reproductive age.
While there has been some discussion among pediatricians regarding whether this recommendation needs to continue to be applied to all infants, at this time, the recommendation remains because of the false negatives and increasing rates of this infection in the population. As such, the American Academy of Pediatrics, American Association for Pediatric Ophthalmology and Strabismus, and the American Academy of Ophthalmology recommend this treatment for all newborns.
Conclusion
The procedures recommended right after birth are based on science and decades of experience. They are also reviewed periodically to ensure that they continue to be necessary and appropriate, as demonstrated by the discussions around erythromycin treatment. While opting out may seem like it is saving the baby from unnecessary pain or interventions, the choice leaves the baby vulnerable. Further, while the risks may seem minimal or theoretical, they are not. These situations are only uncommon because the interventions work. The negative snowball effect applies in two ways here. First, as individual families opt out of single treatments, it becomes easier to opt out of others — inadvertently increasing the risk for one of those choices to end badly. Second, in the case of vaccine decisions, as more families opt out, the risks to the community increase. While the risks are compounded for individual families who opt out of vaccination in an environment in which many are opting out, the reality is that some families who can’t choose vaccination or who didn’t opt out, but for whom the vaccine didn’t work, will also be affected.
Sadly, if we stay on the current path marked by mistrust and a sense of omniscience, the negative snowball effect will make us increasingly aware of the science that is behind these recommendations — and our children will pay the greatest price.
Resources
Hepatitis B
- 9,000 Reasons for Routine Childhood Hepatitis B Vaccination (article)
- Hepatitis B disease and vaccination playlist (videos)
- Hepatitis B: The Disease & Vaccine (webpage)
Vitamin K
- Why Your Newborn Needs a Vitamin K Shot (webpage and video)
- The Boxed Warning for Vitamin K (video)
- Vitamin K Shot Versus Oral Vitamin K (video)
Erythromycin
- Use of Erythromycin in the Prevention of Ophthalmia Neonatorum – 2025 (statement)
- Why Your Baby Needs Erythromycin Eye Ointment After Birth (webpage)
- Erythromycin Eye Ointment for Newborn Pinkeye (Conjunctivitis) (webpage)
Editorial note: This is part 2 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 3 will be published in July 2026 and consider the importance of nuanced understanding that comes from experience.
We’ve all been there. We’re starting something new — a project, an idea, a snowman … wait, what? When we make a snowman, we start with a handful of snow and then roll it around the yard, so it gets bigger and bigger. We apply that concept to other projects or ideas using the term “snowball effect.” We start small and hope our project or idea “snowballs.” You may have also heard of it as a way of getting out of debt — pay off your smallest outstanding source of debt while paying the minimum on other debt. Once the smallest one is paid off, add that amount to the minimum you’ve been paying on your next smallest amount. Do this over and over, increasing the amount you put toward the larger debts each time.
Unfortunately, the snowball effect can work in the opposite way as well, causing increasing amounts of damage — think of terms like “gateway drugs,” “snowball betting” or “Ponzi scheme.” In each case, the entry point is small, but over time, the damage accrues. The negative snowball effect is what we are also starting to see when it comes to unfounded vaccine safety concerns. As the newborn hepatitis B vaccine dose has come under fire, parents are not only opting out of protecting their newborns against this infection, they’re also refusing other lifesaving, decades-old interventions.
Immediate effects: Hepatitis B vaccine
In December 2025, a group of advisors to the Centers for Disease Control and Prevention (CDC) changed a vaccine recommendation that had been in place for more than 30 years. From 1991 until 2025, all babies were recommended to get the hepatitis B vaccine within 12 hours of birth (see image). This strategy virtually eliminated chronic hepatitis B disease in children and young adults. However, the advisors disregarded established science and decades of experience to return to a practice that was tried and didn’t work prior to 1991 — that is to vaccinate only infants of hepatitis B-positive mothers. In making their decision, this advisory group did not just change course in the absence of new evidence, they disregarded decades of existing real-world experience showing that the current recommendation was superior.
Unfortunately, we are already hearing about the effects of this change:
Increased numbers of refusals
Increasing numbers of parents are refusing or delaying the hepatitis B vaccine at birth. While the risk for exposure to hepatitis B in the first year of life is low, it still happens. Further, infection in the first year of life is most likely to result in chronic liver disease (called cirrhosis) or liver cancer, as shown by these age-based risks of developing these life-limiting conditions (see resources at end of article):
- 90 of 100 babies exposed in the first year of life
- 30 of 100 children exposed between 1 and 4 years of age
- 5 of 100 adults following exposure
Refusals even among hepatitis B-positive mothers
Even though the change was made to vaccine recommendations in situations where the mother tests negative for hepatitis B prior to delivery, the effects are being realized beyond this group. Frontline healthcare providers are reporting increased patterns of refusal among families where the mother is known to have hepatitis B. When a woman is positive for hepatitis B, she can pass it to her baby:
- During the birthing process — About 70-90 of 100 babies born to women who test positive will be infected. Without treatment, most of them will develop chronic hepatitis B themselves. However, with receipt of both antibodies and vaccination at birth, only 5 to 15 of 100 infected babies will develop a chronic infection.
- During early childhood — Given that infants born to hepatitis B-positive mothers remain at risk throughout early childhood because of ongoing exposure to the virus in the home, vaccination benefits babies of hepatitis B-positive mothers beyond the birth exposure. Data demonstrate that with vaccination at birth, almost all of these babies are protected.
The snowball effect: Hepatitis B newborn dose and the future
Numerous other considerations are relevant for protecting babies from hepatitis B:
Imperfect systems
Some tests are falsely negative, and about 14 of every 100 pregnant women are never tested before delivery. Even with testing, sometimes results are not received in time, the birth occurs outside of a hospital setting, or the testing and delivery occur in different healthcare systems, making it difficult to access the results. In short, the system is not perfect, so some babies will be missed.
Unknown infections
About half of all chronically infected people in the U.S. do not actually know they have a chronic hepatitis B infection. They won’t find out until they develop liver disease or liver cancer. In the meantime, they can — and do — unwittingly infect other people. Before universal birth dose vaccination, each year about half of the children diagnosed with hepatitis B were infected by someone other than their mother. Often, they never knew where or by whom they were infected.
The universal recommendation reduced hepatitis B infections in children and young adults by 99%. If this recommendation to delay vaccination is followed, we will see those rates rise, which means over time there will be even more people who become chronically infected and spread the disease — the negative snowball effect.
Learning from history
Existing historical data have also established that infants who receive the birth dose of hepatitis B vaccine are more likely to get all of the recommended doses of that vaccine as well as their other childhood vaccines. This, too, will lead to accumulating infections — not only of hepatitis B but possibly also other vaccine-preventable infections. Yet again, the negative snowball effect grows.
Predicting the future
Modeling studies are studies using data that we have available to predict what will happen in different situations. These studies are not perfect because they are trying to predict what might happen, and assumptions that are made could change, causing the models to be inaccurate. However, modeling studies can still be useful for understanding the realm of possibilities.
A recent modeling study of a single U.S. birth cohort (3.6 million infants) evaluated delaying the hepatitis B vaccine birth dose to 2 months for infants with mothers who do not have hepatitis B (as recommended in December 2025 by the CDC committee) or to 12 years (as suggested by the U.S. President). The study predicted:
- If the vaccine is given at 2 months of age to children whose mothers do not have hepatitis B: 20-40 additional cases of liver cancer and 30-60 additional deaths would occur, depending on how well the vaccine recommendations are followed.
- If vaccination is delayed until 12 years of age: About 500 additional cases of liver cancer and almost 800 additional deaths would occur.
Remember that, in both scenarios, each of these are completely unnecessary cancers and deaths because we have a vaccine that works, and changing the recommendation did not do anything to improve safety.
The study also suggested the costs of treating these additional cases would be between $16 million and $22 million if the vaccine is started at 2 months of age and $313 million to $368 million if delayed until 12 years of age. Likewise, the CDC committee suggested screening children after the first dose before getting additional doses, which would increase these costs to $119 million to $123 million at 2 months of age and $409 million to $471 million at 12 years of age. Further, the additional doses are necessary for long-term protection, so we could start to see people who only got one dose become susceptible later in life — adding to the negative outcomes snowball we are building with this change.
The snowball effect: Other newborn protections
Another example of the negative snowball effect is that parents of newborns are also becoming increasingly comfortable refusing other established newborn protections, such as the vitamin K shot and erythromycin eye ointment.
Vitamin K
Babies are born with low levels of vitamin K, making them more prone to prolonged and internal bleeding. (Vitamin K is not transferred to the baby through the placenta nor is it transmitted to the baby through breast milk.) For example, vitamin K deficiency can cause bleeding in the brain that can result in death or long-term neurological damage. Rates are higher in the first hours and days after birth, but the deficiency lingers throughout the first months of life until babies start eating table food. Since the early 1960s, infants have been receiving a single shot of vitamin K shortly after birth, which provides a sufficient supply of the vitamin to protect them throughout the vulnerable first months of life. As increasing numbers of families opt out of this shot for their babies, preventable cases of bleeding and death will increase. Sadly, we have already heard of brain bleeds and deaths following parental refusal of the vitamin K shot.
Erythromycin eye ointment
Infants are exposed to several types of bacteria as they come through the birth canal. Sometimes, the bacteria get in the baby’s eyes, causing pinkeye. One of the most concerning types are the bacteria that cause gonorrhea, called Neisseria gonorrhoeae, as an infection can cause scarring of the cornea and permanent blindness. For this reason, babies are recommended to get erythromycin eye ointment in the first few hours after birth. Many parents hear that the cause is gonorrhea and decide their infant does not require this treatment because they self-assess that they could not have the sexually transmitted infection (STI). However, the bacteria are not always detected in prenatal testing, and more recently the rates of gonorrhea have been increasing among women of reproductive age.
While there has been some discussion among pediatricians regarding whether this recommendation needs to continue to be applied to all infants, at this time, the recommendation remains because of the false negatives and increasing rates of this infection in the population. As such, the American Academy of Pediatrics, American Association for Pediatric Ophthalmology and Strabismus, and the American Academy of Ophthalmology recommend this treatment for all newborns.
Conclusion
The procedures recommended right after birth are based on science and decades of experience. They are also reviewed periodically to ensure that they continue to be necessary and appropriate, as demonstrated by the discussions around erythromycin treatment. While opting out may seem like it is saving the baby from unnecessary pain or interventions, the choice leaves the baby vulnerable. Further, while the risks may seem minimal or theoretical, they are not. These situations are only uncommon because the interventions work. The negative snowball effect applies in two ways here. First, as individual families opt out of single treatments, it becomes easier to opt out of others — inadvertently increasing the risk for one of those choices to end badly. Second, in the case of vaccine decisions, as more families opt out, the risks to the community increase. While the risks are compounded for individual families who opt out of vaccination in an environment in which many are opting out, the reality is that some families who can’t choose vaccination or who didn’t opt out, but for whom the vaccine didn’t work, will also be affected.
Sadly, if we stay on the current path marked by mistrust and a sense of omniscience, the negative snowball effect will make us increasingly aware of the science that is behind these recommendations — and our children will pay the greatest price.
Resources
Hepatitis B
- 9,000 Reasons for Routine Childhood Hepatitis B Vaccination (article)
- Hepatitis B disease and vaccination playlist (videos)
- Hepatitis B: The Disease & Vaccine (webpage)
Vitamin K
- Why Your Newborn Needs a Vitamin K Shot (webpage and video)
- The Boxed Warning for Vitamin K (video)
- Vitamin K Shot Versus Oral Vitamin K (video)
Erythromycin
- Use of Erythromycin in the Prevention of Ophthalmia Neonatorum – 2025 (statement)
- Why Your Baby Needs Erythromycin Eye Ointment After Birth (webpage)
- Erythromycin Eye Ointment for Newborn Pinkeye (Conjunctivitis) (webpage)