Seeing different vaccine information? Start here.
You may see vaccine guidance from more than one trusted source. Sometimes those sources agree. Sometimes they do not. The best place to start is with one question: What am I trying to find out?
Four things that can sound like the same thing
These ideas are closely related, but they answer different questions. Knowing the difference can make vaccine information much easier to understand.
Evidence
Evidence is what the research shows. Vaccines are studied before approval. Safety is also monitored after vaccines are in use.
Recommendations
Experts review the evidence and decide how it applies in practice. A recommendation tells us who is likely to benefit from a vaccine.
Requirements
A requirement comes from a law or policy. It is not the same as a medical recommendation. School vaccine rules are one example.
Your health
Medical guidance still has to be applied to an individual person. Age matters. Health history matters. Pregnancy can also change what is recommended.
What do you need to know right now?
Start with the question you want answered.
A recommendation does not automatically mean a requirement.
Medical recommendations are based on evidence about the benefits and risks of vaccination. A legal requirement answers a different question. For example, Pennsylvania decides which vaccines are required for school. Medical organizations decide which vaccines they recommend for patient care.
Why might trusted sources say different things?
Science does not stop when a recommendation is published. New research continues to appear. Organizations may review that research at different times or use different processes to turn evidence into guidance.
What should I look at when guidance differs?
Start with the source. Ask who published the recommendation and when it was updated.
- Is the source explaining scientific evidence?
- Is it making a medical recommendation?
- Is it explaining a law or policy?
- Does the information apply to your situation?
A difference between two recommendations does not automatically mean that one source is ignoring science. Look at the evidence each organization reviewed and how it reached its decision.
If the question is about your own health, a qualified healthcare professional can help you apply the guidance to your situation.
Find the answer to your question
Whenever possible, these links take you directly to the organization responsible for the guidance.
What vaccines are recommended for children and teens?
Several medical organizations publish vaccine guidance for children. Their recommendations are based on reviews of scientific evidence. You can read the guidance directly from each source below.
What vaccines are recommended for adults?
Vaccine recommendations can change as we get older. A person's health can also affect which vaccines are recommended.
What vaccines are recommended during pregnancy?
Pregnancy changes how some vaccine recommendations are applied. Timing can matter. Some vaccines are recommended during pregnancy while others are not.
What vaccines does Pennsylvania require for school?
Pennsylvania sets its own school vaccine requirements. These requirements are separate from national medical recommendations.
How are vaccines tested and reviewed?
Vaccine testing begins before a vaccine is approved. Clinical studies help researchers measure whether it works and identify possible risks. The FDA reviews that evidence before deciding whether a vaccine can be approved for use in the United States.
The process does not end at approval. Safety monitoring continues after a vaccine is being used by the public.
What's in vaccines?
A vaccine contains ingredients that serve specific purposes. The active part teaches the immune system what to recognize. Other ingredients may help the vaccine work properly or remain stable.
What happens when someone reports a possible vaccine side effect?
One system used to watch vaccine safety is VAERS. Anyone can submit a report after a health problem happens following vaccination.
That report is important, but it does not prove that the vaccine caused the health problem. Researchers look across reports for patterns. A pattern can be a signal that something needs a closer scientific review.
Where can I get a vaccine or help locally?
If you are ready to get vaccinated, local resources can help you find a provider. You can also find help locating vaccine records.
How ACIC chooses vaccine information
ACIC starts with scientific evidence. We use medical organizations that review vaccine research and publish clinical guidance.
When the question involves Pennsylvania law or school requirements, we use Pennsylvania government sources.
We also try to link directly to the organization responsible for the information. Recommendations can change. Linking to the original source makes it easier to see the most current guidance.
Our goal is not to avoid difficult questions. It is to answer them with evidence and enough context to understand what that evidence means.
Read ACIC's Clinical Source Standard →
This page provides general educational information. It does not replace medical advice from your own healthcare professional.