Top Vaccine Questions Answered: What You Need to Know
Vaccines save millions of lives each year, yet they are often misunderstood. This article explains how vaccines work, why boosters are important, what potential side effects to expect and more.
How does a vaccine work?
A vaccine teaches your body how to fight harmful pathogens — like viruses or bacteria — without making you sick. It uses a harmless version or piece of the pathogen, so your body's immune system learns how to respond quickly if the real one shows up. You may have mild symptoms after receiving a vaccine, but you will also gain protection that lasts a long time.
What are vaccine side effects?
Vaccines may have some mild side effects like low-grade fever, feeling a bit rundown or decreased appetite for a day or two. These are actually signs that your immune system is doing its job.
How were vaccines developed?
Vaccines have been around for more than a century, and the idea of inoculation goes back even further. In the 1700s, Dr. Edward Jenner noticed that milkmaids exposed to cowpox developed immunity to smallpox and experimented with an inoculation. Widespread vaccination programs began in the early 1900s, and a major breakthrough came in the 1950s with the development of the polio vaccine.
How are diseases chosen for vaccine development?
Illnesses that cause the most sickness and death, especially among children, are targeted for vaccine research. Scientists commonly look at what illnesses are filling pediatric wards and ICUs.
How are vaccines approved for use?
Vaccines go through a rigorous multi-step process overseen by the U.S. Food and Drug Administration (FDA) prior to approval for public use.
- Nonclinical studies or preclinical trials check for safety and whether the vaccine triggers an immune response.
- Clinical trials begin with small studies that look at safety of the vaccines, dosing and immune response.
- Subsequent trials with larger populations and studies focus on dosing, long-term side effects and whether the vaccine actually works in the general population.
- After approval, ongoing safety monitoring in clinics look for rare side effects.
How is the vaccine schedule developed?
A group within the U.S. Centers for Disease Control and Prevention (CDC), that is similar to a governing body for vaccines, determines the CDC vaccine schedule. Other groups, including the American Academy of Pediatrics (AAP) and the American Medical Association (AMA) provide input for the vaccine schedules.
What is a combination vaccine?
Combination vaccines, such as the measles, mumps and rubella (MMR) vaccine, protect against multiple illnesses with one shot. This means fewer needles and fewer appointments. These vaccines are carefully tested to make sure they are safe and work well.
Why are booster shots required?
The protection a vaccine offers can decrease over time. A booster “reminds" your immune system how to fight off a pathogen. Booster shots can also help your body respond better to newer versions of the virus, called variants. Not all vaccines need boosters.
What is herd immunity?
When enough people in a population are protected — either through vaccination or natural infection — a disease has a harder time spreading. This is called herd immunity or community immunity. It helps protect people who cannot get vaccines, such as newborns or those with health conditions like cancer.
If fewer people get vaccines, we can lose herd immunity — and the disease can more easily spread. This has recently occurred in some regions of the country with measles, resulting in large outbreaks of the illness.
Where can I get reliable information about vaccines?
Your doctor is a source you can trust for reliable answers to your vaccine questions. They will give you evidence-based information and address any concerns you have.
Cold and Flu;Immunizations
