What are the main parental worries about vaccines?

Happy kid getting a vaccine

As a neonatologist (“baby doctor”), I want to talk about frequent worries and questions that parents have about vaccinating their infants and children. We, the health care providers, owe You a good explanation why we want to administer something to your little ones. 

In full disclosure, I want to emphasize that I am not anti-vaccinations, and the purpose of my article is to ease your worries about vaccines. Ever since Edward Jenner invented the first vaccine for smallpox, millions of lives have been saved. (Link to History of Vaccines: https://www.historyofvaccines.org/timeline/all)

If, after reading my article, you want more advanced information, please refer to references I included below my article (Link 1, Link 2).

What are the main parental worries about vaccines? 

Natural Methods of improving immunity in children are better than vaccinations.

There are only three ways to acquire immunity and protection from infectious diseases. Mothers can pass antibodies to their babies before and after birth. Mother’s antibodies (IgG) can enter into newborn babies’ circulation through the placenta before baby is born, or the baby can receive some antibodies (IgA) in breast milk. 

Newborns are protected only against some diseases that way, and acquired immunity decreases with time as antibodies can survive in our circulation for no more than six months. This type of immunity is called passive immunity (Mother gave it to us; we did not acquire it through disease or immunizations). 

Another way of acquiring immunity against the disease is to get sick in a natural way. Unfortunately, it may be dangerous for the individual. The premiss on which vaccination programs rely is that certain infectious diseases can be hazardous for some people, causing disabilities or death. Therefore, it is worthwhile to take some small risk and be vaccinated rather than take a more significant risk of being unprotected and get sick with the possibility of developing severe complications or death.

A third way we can get protection is to get vaccinated. Since vaccinations are “gentler” than the real disease, for some disorders to get protection, we need to give several doses of the vaccine separated by specific time intervals. Getting a vaccine is a smart way to acquire immunity. 

Most diseases that are targeted by immunizations can be dangerous. We do not fear the “simple” or “benign” course of infectious diseases of childhood. What we fear are rare complications they carry, such as disabilities or death. 

Giving several different vaccines at the same time may be dangerous.

Frequently, parents are concerned that giving multiple doses of the same vaccine overtime or giving several different vaccines at the same time can overburden a child’s immune system and be dangerous.

This concern is unfounded because each of us is literally bombarded with antigens and bacteria every day, thus our immune system and similarly child’s immune system has to tackle it every day. 

Many dangerous diseases are acquired early; during the first two years of life. We give several vaccines at the same time to provide timely protection to infants.

Many vaccines have to be given several times in order to provide optimal and maximum protection. Usually, vaccines contain weakened antigens or microbes. Therefore it takes several exposures for the individual to develop a robust immune response and defensive mechanisms. 

Institute of Medicine, in its study of data on the safety of dosing schedules, concluded that there is no evidence supporting the notion that immunization schedule is unsafe.

Besides, in order to ensure the safety of the administration of several vaccines in one shot, all new vaccines are required for their approval to be studied with already existing vaccines. That way, we can learn if their administration influences the effectiveness and safety of currently used immunizations. 

Vaccines are ineffective.

Vaccination programs in the USA and all over the world have been incredibly effective. A recent analysis of one single birth cohort of babies vaccinated against 13 diseases estimated that they avoided 20 million cases of illness and 40 thousand deaths were prevented (Link to the study)

Among diseases that we vaccinate for in the USA, all the conditions have been reduced by more than 90%, and many have been eliminated or reached reductions in incidence close to 99%.

Sadly, due to much of disinformation, particularly on social media, parents started refusing vaccinations in large numbers, and some diseases such as measles or pertussis, chickenpox are reemerging. 

Vaccines can cause or contribute to the development of other diseases.

Some parents are worried that vaccines cause or contribute to the development of other diseases. Those most frequently cited are: 

  • Sudden Infant Death Syndrome (SIDS)
  • Autism
  • Immune dysfunctions
  • Diabetes
  • Neurologic disorders
  • Allergic rhinitis
  • Eczema or asthma

Those claims are false. Many high-quality studies and reports such as by Institute of Medicine report (Link 1) debunked those claims. In fact, the author of the first infamous article about the connection between the MMR vaccine and autism was banned from the doctor’s community, and his report was withdrawn and erased from the database. 

Many years after the initial publication of the said article, we found out that data was presented selectively and fraudulently. Also, the principal author of the study had connections and had been funded by lawyers litigating cases against vaccine producing pharmaceutical companies.

Vaccines weaken the immune system in children.

Many naturally occurring infectious diseases weaken the immune system. Examples of such conditions are flu, measles, or chicken pix. However, data on the effectiveness of vaccinations is indisputable.

Immunized children have a lower incidence of infectious diseases. Therefore it should be inferred that their immune systems are stronger, not weaker. 

Vaccines should be delayed or spaced out more.

The problem with delaying or spacing out immunizations more is that if we do not vaccinate infants or small children on time, we do not protect the most vulnerable populations.

Newborns, infants, and small children need immunizations most because their immune systems are immature and have very few defensive mechanisms on its own.

Furthermore, many infectious diseases are most aggressive and dangerous early on in their lives, which can be debilitating and lead even to the death of a child.

Vaccines contain toxic substances such as thimerosal.

Pharmaceutical companies producing vaccines use preservatives in some of them. Chemicals are used in order to prevent the growth of bacteria or fungi in multi-dose use vials. 

Thimerosal is a mercury-containing organic compound that has been used in the production of many pharmaceutical products, including vaccines. It has been used as a preservative since the 1930s to help prevent contamination of drugs and immunizations. 

Thimerosal use has been studied by many, and no significant harm from this product was proved other than rare mild allergic reactions. 

If you are concerned about thimerosal, you can request a thimerosal and preservative-free vaccine for your child. In the USA, all routinely recommended vaccines are available in thimerosal-free – single dose form. 

You will find much more information about thimerosal on the FDA website here.

In Summary:

Vaccines are an essential preventive measure available to individuals and society. Undisputedly, millions of lives have been saved to date, thanks to robust vaccination programs. 

Parents still have many concerns regarding the safety and effectiveness of some or all of the vaccines. Also, some parents have religious reasons to refuse vaccines for their children. 

If you are a parent and have concerns or worries regarding vaccines or vaccination schedules, the best approach is to read more about those issues from reputable resources of information and discuss your concerns with your pediatrician. 


  1. Institute of Medicine Review of the safety of various vaccinations
  2. Safety of Childhood immunization schedules by National Academy of Medicine

You may be also interested to read my article on RSV infections in children here.


This article is only for general information purposes. It should not be viewed as any medical advice. There is a small chance that information here may be inaccurate. You should always discuss all health-related matters with your doctor before making any decisions that may affect your health or health of your family members.


Dr.Wisniewski is a board-certified pediatrician and neonatologist with over 20 years of clinical experience in the USA. He authored the book: "Babies Born Early - A guide for Parents of Babies Born Before 32 Weeks" Dr.Wisniewski loves educating parents on various health conditions affecting their newborn babies and children.

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