VaIf you look at the list of vaccines children need, you may think it’s long. That’s not the case, though. Each vaccine plays an important role in preparing children’s immune systems to protect them from potentially deadly diseases. This protection typically takes a few weeks to build and, in many cases, can last a lifetime. However, some vaccines, such as those for tetanus or seasonal flu, require occasional booster doses to maintain immunity.

When it comes to protecting children from some of the diseases out there, vaccines are one of the most effective tools available, and understanding the science behind vaccines can help explain why multiple doses are necessary to build long-lasting immunity.

Strengthening the Immune Response

Our immune system learns how to fight infections by encountering germs, either naturally or through vaccination. When a vaccine introduces a weakened or inactive virus or bacteria into the body, the immune system responds by producing antibodies.

For some diseases, one dose isn’t enough to trigger a strong or lasting immune response. Booster shots are needed to reinforce the body’s ability to recognize and fight off the disease if exposed in the future. This is why vaccines, like diphtheria, tetanus, and pertussis (DTaP), require multiple doses over time.

Providing Immunity in Steps

Some vaccines are given in a series because they work best when introduced gradually. For example:

● The hepatitis B vaccine is given in a three-dose schedule because the first dose introduces the virus to the immune system, the second dose boosts response, and the third dose ensures long-term protection.

● The polio vaccine is administered multiple times in early childhood to build a strong defense and prevent outbreaks.

Each dose works strategically for your immune system, strengthening its ability to recognize and eliminate disease-causing agents.

Compensating for Weakened Immunity Over Time

Some vaccines require booster shots because immunity from the first dose weakens over time. The tetanus vaccine needs to be repeated every 10 years to make sure that the immune system remains ready to fight off the bacteria if exposed.

This is the same as the influenza (flu) vaccine, that’s needed annually because flu viruses mutate and change frequently. Each year’s flu shot is formulated to match the most common flu strains circulating at that time.

Increasing Effectiveness with Advancements in Science

Vaccine schedules are based on decades of research and are constantly refined as new data becomes available. Scientists test and study vaccines to determine the best number of doses required for maximum effectiveness. The goal is to minimize risks while ensuring long-term protection.

In the early days of the human papillomavirus (HPV) vaccine, it required three doses, but research showed that two doses were just as effective in younger people. This adjustment reduces the number of shots needed while maintaining the same level of protection against cancers caused by HPV.

Can Too Many Vaccines Overwhelm the Body?

One common concern that often comes up is whether receiving multiple vaccines can overwhelm the immune system. However, scientific research shows that the immune system is equipped to handle multiple vaccines at once. Every day, children encounter thousands of bacteria and viruses in their environment, and the number of antigens (substances that trigger an immune response) in vaccines is small compared to what the body naturally encounters.

The immune system is adaptable and capable of responding to multiple threats simultaneously. Vaccines are carefully tested and scheduled to ensure they don’t overload the immune system.

Skipping vaccines out of concern for “too many shots” can leave a child open to contracting preventable disease, which can be much more dangerous than any temporary side effects of vaccination.

Vaccination Saves Lives

Ensuring that your children stay on track and receive all the necessary vaccines in the outlined schedules is essential for preventing serious diseases. Skipping doses can leave them partially protected, increasing the risk of infection and spread.

Vaccines are safe, thoroughly tested, and continue to be monitored for effectiveness. Completing the full series of vaccine doses strengthens immunity, prevents outbreaks, and protects future generations from diseases, like measles, that were once deadly.

Sources:

CDC: Reasons to Vaccinate

National Foundation for Infectious Diseases: 10 Reasons to Get Vaccinated

U.S. Food and Drug Administration: Vaccines for Children — A Guide for Parents and Caregivers

There are several illnesses and viruses parents need to be on the lookout for, especially with newborns or young children. One illness often overlooked is Hepatitis A, a liver infection caused by the Hepatitis A virus (HAV). While it may not be as widely discussed as other vaccine-preventable diseases, Hepatitis A has the potential to cause serious illness in children.

What is Hepatitis A?

There are five different types of hepatitis: A, B, C, D, and E. Hepatitis A is a highly contagious virus that affects the liver. Unlike Hepatitis B and C, it doesn’t lead to long-term liver damage, but it can still cause severe illness, particularly in young children. The virus spreads easily, especially in areas with poor sanitation or where hygiene practices are not consistently followed.

Although most people recover completely from Hepatitis A, the infection can last for weeks or even months, causing discomfort and disruption to everyday life. In rare cases, it can lead to severe complications, especially for children who may have pre-existing liver conditions.

How Do Kids Get Hepatitis A?

Hepatitis A is primarily spread through the fecal-oral route, meaning it is transmitted when a person unknowingly ingests the virus after coming into contact with contaminated objects, food, water, or an infected person.

Young children are vulnerable because the virus spreads easily through poor hand hygiene. Some of the most common ways children contract Hepatitis A include:

● Eating food that was handled by someone who didn’t wash their hands properly after using the bathroom.

● Drinking water or eating produce contaminated with the virus, which can happen when traveling to certain regions.

● Touching contaminated surfaces, such as toys or shared objects, and then putting their hands in their mouths.

● Having close contact with an infected person, including sharing utensils or personal items.

● Being exposed in daycare or school settings, where outbreaks can spread quickly.

Because the virus can survive on surfaces for long periods, it spreads easily in group settings.

What Happens if a Child Gets Hepatitis A?

Not all children show symptoms when infected with Hepatitis A, but when they do, the illness can last for several weeks or even months. Symptoms can range from mild to severe and may include:

● Fever

● Loss of appetite

● Nausea and vomiting

● Abdominal pain

● Dark urine and pale stools

● Yellowing of the skin or eyes (jaundice)

While most children recover fully without long-term effects, Hepatitis A can sometimes lead to hospitalization, dehydration, and in rare cases, severe liver complications.

When Should Kids Get the Hepatitis A Vaccine?

The Hepatitis A vaccine is the most effective way to protect children from infection. It is part of the routine childhood vaccination schedule in the United States.

The recommended vaccination schedule includes:

● First dose: Given between 12 and 23 months of age.

● Second dose: Given at least six months after the first dose.

If a child was not vaccinated as a toddler, they can still receive the vaccine at any age. It is recommended for children who are traveling to countries where Hepatitis A is common, attending daycare, or living in communities where outbreaks are known to happen. The vaccine provides long-term protection and is highly effective in preventing infection.

How Can Parents Prevent Hepatitis A?

There are several things parents can do to help protect their children against Hepatitis A. Teaching and encouraging good hygiene habits is always important for reducing the risk of illness transmission. Some key prevention measures include:

● Ensuring children wash their hands thoroughly with soap and water, especially after using the bathroom and before eating.

● Making sure all food is cooked properly and prepared under sanitary conditions.

● Providing only clean, safe drinking water, particularly when traveling.

● Avoiding sharing utensils, cups, or personal items with others.

Hepatitis A is a serious but preventable illness. By ensuring that children receive the recommended vaccinations and practicing good hygiene, parents can significantly reduce the risk of infection. If you are unsure whether your child is vaccinated, speak with your pediatrician about getting them up to date.

Sources:

CDC: Hepatitis A Vaccine Administration

U.S. Department of Health and Human Services: Hepatitis A Basic Information

WHO: Hepatitis A