How Vaccines Work & What Happens When You Don't Get Them

A gloved-hand gets a vaccine ready and explains how do vaccines work

Vaccines are vital for your health, and that’s why both babies and adults should stay up-to-date on immunizations. They’re also safe. In fact, Stephen Rinderknecht, DO, UnityPoint Health says they are safer than most of the foods we eat! But you may still wonder: how do vaccines work? Dr. Rinderknecht has that answer, plus he identifies which vaccines have live viruses, vaccine testing protocols and three reasons to stick with your doctor’s recommended vaccine schedule.

How Do Vaccines Work?

“When you get a vaccine, the body is exposed to a harmless material that mimics a disease-causing microbe,” Dr. Rinderknecht says. “Our body recognizes it as a danger and produces antibodies and white blood cells to protect us in the future, if we ever get exposed to the real thing.”

Only a few vaccines include a live virus. Those include the MMR (measles-mumps-rubella), varicella, rotavirus and the nasal flu vaccine.

“The virus in these vaccines has been treated in a way that makes it not cause disease, but still elicits an immune system response that recognizes and protects us against the real or wild virus,” Dr. Rinderknecht says.

How quickly the body can build up immunity depends on a lot of factors, including age, the type of vaccine being given, maternal antibodies, genetics, nutritional factors and coexisting diseases.

“Our annual flu vaccine takes about two weeks to become effective. However, the initial DTaP (Diphtheria, Tetanus, and Pertussis) vaccine in infants takes a series of three, two months apart before much protection is seen,” Dr. Rinderknecht says.
Ask your doctor how long it’ll take any of your recent vaccines to be most effective.

Why are Vaccines Important?

“If a high level of the population is vaccinated, a contagious individual introduced to the community will not result in the spread of the disease. However, if there is a low vaccine rate, the disease will spread among those in which the vaccine wasn’t effective (and those too young or too compromised to be vaccinated),” Dr. Rinderknecht says.

He identifies three main reasons why vaccines are important.

  • Decreases the transmission of disease
  • Prevents suffering and death to ourselves or loved ones from an avoidable cause
  • Reduces the chances of having the financial burden of medical cost associated with disease conditions

“The only disease totally eliminated from vaccination is smallpox. The next closest to elimination is polio. It has been eliminated from the Western Hemisphere since 1991, but still lives on in a few countries in Asia. International travel allows many diseases to be just a stroll away at the local market,” Dr. Rinderknecht says.

However, it is still possible for you to get the disease after being vaccinated.

“No vaccine is 100 percent effective—for example, the MMR (measles-mumps-rubella) is 95-97 percent effective against measles. Our annual flu vaccine varies from 25-70 percent effective. Often, a vaccine may not totally prevent a disease, but will alter and reduce the severity,” Dr. Rinderknecht says.

Dr. Rinderknecht says another example is the rotavirus vaccine. It’s only about 70 percent effective, but it is about 95 percent effective at preventing severe disease that results in dehydration and hospitalizations.

Why are Vaccines Important for Children?

Some caregivers worry about the vaccination schedule for very young children. Dr. Rinderknecht says you should stick to the schedule provided by your care team for several reasons.

  • Backed by science. There is data to support the safety and efficacy of vaccines when they are administered together. There is a lack of data on alternative schedules.
  • Better protection. When a schedule is spread out, immunity is delayed and that infant won’t be protected if he/she encounters the disease. Following the vaccination schedule supports the health of your child.
  • Right vaccinations, right time. By sticking to the recommended schedule, there’s no guessing by you or your care team if your child is receiving the right vaccinations at the right time

If you’re worried about autism, Dr. Rinderknecht says don’t be.

“No vaccine is associated with causing autism. Now with about 100 studies, this is becoming a dead issue,” Dr. Rinderknecht says.

To make sure a vaccine is both safe and effective, it must first go through a series of tests before it can be licensed. The test is called a clinical trial and involves more than 10,000 people. In this test, some people receive the new vaccine and others get a placebo or an established vaccine. Then, the researchers compare the side effects.

“Once a vaccine is licensed and recommended, the safety monitoring continues and even become more robust. Extremely rare side effects may not be discovered in a study of 10-50,000 people. But, when used in the general population with millions being monitored, those rare side effects will be discovered,” Dr. Rinderknecht says.

To date, Dr. Rinderknecht says it seems parents or caregivers are most concerned with the HPV (Human Papillomavirus) vaccine. While inaccurate information has led some to believe the HPV vaccine isn’t safe, he says it is. The truth is it can prevent cervical cancer in girls and protect both boys and girls from several other common cancers including both throat and neck cancers, anal cancer and genital warts.

“HPV is the most highly tested of all vaccines. It’s been used for 12 years and over 100 million doses given with no long-term side effects,” Dr. Rinderknecht says.

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