All vaccines
Clearing up confusion about vaccines
Misunderstandings about vaccines have circulated for years; learn more about the science behind vaccines.
Dr. David Weber · August 13, 2025
6 min read
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Key takeaways
- Vaccines are carefully and thoroughly tested and monitored for safety.
- Vaccines help protect people and communities from serious diseases.
- Misinformation is common; understanding the facts backed by the evidence is key to making more informed health decisions.
It can be easy to feel overwhelmed by conflicting information about vaccines. From social media rumors to debates over the dinner table, many common concerns stem from misunderstandings or outdated claims. By looking at what the evidence shows, you can better separate fact from fiction and make more confident, informed health decisions.
Can getting more than one vaccine at once overload your immune system?
Your immune system fights off germs every day—way more than what’s in a vaccine.
- Vaccines only use a small part of a germ (virus or bacteria) to help your body learn how to protect itself and common side effects are usually mild and temporary.
- Even if you get more than one vaccine at a time, it can be handled by your immune system.
- The Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) have recommended people receive more than one vaccine in a single visit where clinically recommended to help stay up to date on protection without needing multiple appointments.
Are serious vaccine side effects common?
Most vaccine side effects including those for respiratory vaccines are mild and short-lived—like a sore arm or fever.
- Serious side effects are rare and are closely followed through safety systems like VAERS (Vaccine Adverse Event Reporting System). Visit the Center for Disease Control and Prevention’s Vaccine Safety Page for more information.
- Vaccination remains one of the most effective ways to help prevent these serious outcomes.
Vaccines are one of the most studied and monitored medical tools in history.
Are vaccines needed if we have good hygiene and sanitation?
Clean water and good hygiene help reduce disease spread, but they’re not enough to fully stop the spread of germs (viruses and bacteria).
- Vaccines work by training and strengthening the immune system to help prevent infection against certain diseases—something hygiene alone can’t do.
- Airborne transmitted illnesses like respiratory illnesses (e.g., the flu, COVID-19, pneumococcal pneumonia, and RSV) can sometimes be transmitted regardless of hygiene.
- Diseases like measles have increased in areas when vaccination rates dropped. Even if a disease is uncommon in the United States, without continued vaccination, disease rates can increase.
Is natural immunity better than vaccination?
While natural infection can lead to immunity, it often comes at a cost:
- Diseases like measles, chickenpox, and COVID-19 can cause serious complications, hospitalizations, or even death.
- For example, before chickenpox vaccination became common in the early 1990s, the United States saw 10,500–13,500 hospitalizations and 100–150 deaths annually. Today, thanks to vaccination, those numbers have dropped to fewer than 1,400 hospitalizations and 30 deaths per year.
- Vaccines offer protection by helping to train your immune system.
Have vaccines ever completely eradicated a disease?
Vaccines have had a profound impact on global health.
- Smallpox is one of the human diseases that has been eradicated—meaning it no longer exists in the world, and you cannot catch or spread it—and it was done through vaccination.
- Polio was caused by 3 types of closely related germs. Polio virus type 2 was eradicated worldwide in 1999 and polio virus type 3 was eradicated worldwide in 2020. Only polio virus type 1 still exists and it causes disease in only a few countries.
- Diseases like measles and rubella have seen major declines thanks to widespread immunization but are now increasing due to decreasing vaccination rates.
The bottom line on vaccine misunderstandings
Vaccines are one of the most carefully and thoroughly studied medical tools in history. While it’s natural to have questions, it’s important to base decisions on facts. Understanding the evidence behind vaccines helps protect not just you, but your entire community. If you’re still unsure, talk to a healthcare provider or visit VaxAssist.com to check your eligibility, and find and schedule respiratory vaccinations.
Frequently asked questions
References
Bhadelia N, White L, Gostin LO. The Perfect Storm: Measles Resurgence in an Era of Vaccine Disinformation and the Dismantling of Public Health. Milbank Quarterly Opinion. April 10, 2025. https://doi.org/10.1599/mqop.2025.0410
Bi K, Bandekar SR, Bouchnita A, Fox SJ, Meyers LA. Annual hospitalizations for COVID-19, influenza, and respiratory syncytial virus, united states, 2023–2024. Emerg Infect Dis. 2025;31(3):636-638. https://doi:10.3201/eid3103.240594
Ginglen JG, Doyle MQ. Immunization. In: StatPearls. StatPearls Publishing; 2025. Global immunization efforts have saved at least 154 million lives over the past 50 years. The World Health Organization. April 24, 2024. https://www.who.int/news/item/24-04-2024-global-immunization-efforts-have-saved-at-least-154-million-lives-over-the-past-50-years
Impact of U.S. Chickenpox Vaccination Program. The Centers for Disease Control and Prevention. April 22, 2024. Accessed July 23, 2025. https://www.cdc.gov/chickenpox/vaccination-impact/index.html
Multiple Vaccines at Once. The Centers for Disease Control and Prevention. December 20, 2024. Accessed July 7, 2025. https://www.cdc.gov/vaccine-safety/about/multiples.html
Poliomyelitis (polio). The World Health Organization. Accessed July 23, 2025. https://www.who.int/health-topics/poliomyelitis
Pollard AJ, Bijker EM. A guide to vaccinology: from basic principles to new developments. Nat Rev Immunol. 2021;21(2):83-100. https://doi.org/10.1038/s41577-020-00479-7
Tan L, Trevas D, Falsey AR. Adult Vaccine Coadministration Is Safe, Effective, and Acceptable: Results of a Survey of the Literature. Influenza Other Respir Viruses. 2025;19(3):e70090. doi:10.1111/irv.70090
Vaccine Side Effects. The United States Department of Health and Human Services. May 6, 2022. Accessed June 25, 2025. https://www.hhs.gov/immunization/basics/safety/side-effects/index.html
Vaccines and immunization: Vaccine safety. The World Health Organization. March 26, 2025. Accessed July 23, 2025. https://www.who.int/news-room/questions-and-answers/item/vaccines-and-immunization-vaccine-safety