Talking Points
Messaging research from PHCC and Perry Undem shows that messages about scientific rigor, the effectiveness of vaccines throughout history, and the seriousness of the illnesses vaccines protect against lead to more discussion and curiosity about vaccines.
Use the following talking points to discuss vaccine development, safety, and effectiveness.
Updated August 2025
Vaccine Development Timeline
- Every vaccine goes through a transparent and rigorous development process. Vaccines are constantly monitored, from the early stages of research to their public release, and beyond.
- Some vaccines undergo a shorter-than-usual timeline for the standard development and testing phases. These vaccines are developed quickly because of decades of previous vaccine research, global collaborations, and overlapping development and testing phases.
Vaccine Review and Monitoring
- The Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) require a rigorous vaccine testing process because it ensures that people receive the greatest benefit from vaccines in the safest manner.
- The CDC and FDA continue to monitor the vaccine development process, manufacturing facilities, and overall safety and effectiveness even after it is released to the public.
Vaccine Safety and Effectiveness
- Vaccines are the best way to protect yourself against preventable, serious diseases that once commonly harmed or killed people, such as smallpox and polio.
- Vaccines have a proven track record of reducing disease. Many people you know are vaccinated against diseases that once were very common and caused serious illness and even death.
What to Know About mRNA Vaccines
mRNA vaccines are in the news after the U.S. Department of Health and Human Services cancelled $500 million in research grants for mRNA technology in August 2025, asserting, without sharing any evidence, that the vaccines are unsafe and ineffective. Use these talking points to answer your community members’ questions about mRNA vaccines, how they are developed, and the evidence for their safety and effectiveness.
Added August 11, 2025
What is an mRNA vaccine?
An mRNA vaccine is a type of vaccine that helps the body protect against diseases and severe illness. Scientists use several approaches or technologies to develop vaccines, and each approach creates a different vaccine type. All types of vaccines have the same goal of protecting people from disease, but they achieve it in different ways.
For example, most flu vaccines activate the body’s immune response against the flu virus by introducing either an inactive or weakened virus. In contrast, mRNA technology does not use any part of the virus. An mRNA vaccine introduces a short segment of mRNA that instructs the body to make a part of the virus that can activate the body’s immune response but is too small to cause the disease. The immune system then creates the tools to fight the virus whenever it encounters it. Once the mRNA delivers the instructions, the body breaks down the mRNA and it is completely cleared from the body, leaving behind only the ability for the body to fight a virus.
mRNA technology is the basis for the COVID-19 vaccine. Over 270 million people in the United States have received at least one dose of the COVID-19 vaccine. The vaccine’s widespread use during the pandemic and its continued use today demonstrate its safety.
Why do mRNA vaccines matter?
mRNA vaccines are effective at protecting against disease and are quicker to produce than other vaccine types. COVID-19 vaccines that use mRNA technology have helped prevent severe illness, hospitalization, and death for millions of people in the United States. Moderna and Pfizer COVID-19 vaccines that use mRNA technology are still used to protect against COVID-19 and its severe effects.
While some vaccine types, like the inactive vaccines used to protect against the flu, can take months to create, mRNA technology allows scientists and vaccine manufacturers to produce vaccines quickly. Respiratory diseases, like COVID-19, can change rapidly and have many variants. mRNA technology enables the development of updated vaccines responsive to those changes and helps prevent the COVID-19 variants most likely to be in circulation. The speed and safety of mRNA technology can be particularly helpful in responding quickly to the spread of pandemics.
Are mRNA vaccines safe?
Scientists have been researching mRNA vaccine development for decades. In 2018, the FDA approved the first drug made with mRNA technology. Years of mRNA research, testing, and approval processes supported the emergency development and use of the technology in the first COVID-19 vaccines in 2020. COVID-19 vaccines that use mRNA technology follow the same rigorous processes to ensure safety and efficacy as other vaccine types.
Billions of people worldwide have safely received at least one dose of the COVID-19 vaccine, which uses mRNA technology. Claims that mRNA vaccines are unsafe or cause permanent damage to the body have not been supported by evidence.
How will changes to mRNA funding impact communities?
Changes to mRNA funding could reduce the use of this effective technology to fight disease and illness, and pause or eliminate life-saving advancements for other chronic diseases and respiratory illnesses.
What to Know About Placebo-Controlled Trials and Other Kinds of Comparison Studies
Information about placebo-controlled trials is appearing in the news and social media more frequently. Use these talking points to answer your community members’ questions about placebo-controlled trials, when they are typically used, and when a different type of comparison study may be used.
Added June 20, 2025
- One way that scientists test the safety and efficacy of a new vaccine is by comparing it to an immunologically inactive substance: a substance that does not include any active elements of a vaccine. An immunologically inactive substance is also called a placebo. In a comparison study, also known as a placebo-controlled trial, some participants receive the vaccine being tested. The other participants receive a placebo, like a saltwater solution, that does not actually impact the body’s response to an infection. Comparing the outcomes of these two participant groups helps scientists determine whether receiving the vaccine is better than not receiving the vaccine.
- Other kinds of comparison studies don’t use an immunologically inactive placebo but still provide the evidence needed to determine whether a vaccine is safe and effective. For example, when testing a vaccine intended to replace an existing, older version of the same vaccine, researchers often conduct an active control (or comparator) trial, in which some participants receive the older version of the vaccine, and the rest of the participants receive the vaccine that is undergoing testing.
- In most cases, it is unethical to give trial participants an immunologically inactive placebo if an older version of a vaccine exists. Those participants and/or their caregivers would not know that they haven’t received a vaccine, putting them at unnecessary risk for serious illness. Comparing a new vaccine with an older version provides protection to trial participants and still produces the necessary data to understand whether a vaccine is safe, effective, and ready for public use.
- Ultimately, all vaccines are tested through some kind of comparison trial. Every vaccine is different, and so are the methods used to test each vaccine. Scientists determine which kinds of comparison trials to use based on what is safest, most ethical, and builds on the foundation of what has been learned from previous trials.
- Once a new or updated vaccine is being used by the public, the CDC and FDA continue to monitor its safety and effectiveness through various reporting systems, safety assessments, and collaborations with other government agencies and non-government partners.
