Previous article
Thrombocytosis: Rapid Evidence Review
Apr 2026
Next article
Systemic Sclerosis: Evaluation and Treatment

Vaccine Adverse Effects: An Overview

Sarah Coles, MD

American Family Physician. 2026;113(4):339-348.

Author disclosure: No relevant financial relationships.

This clinical content conforms to AAFP criteria for CME.

Related Curbside Consultation, Vaccine Conversations: Meeting Patients Where They Are, is available

Published online March 16, 2026.

Vaccines are one of the most successful medical advances in modern times. Patients are increasingly questioning the necessity of immunizing themselves and their families, and family physicians should be aware of the risks and benefits of recommended immunizations to accurately counsel about adverse effects and address vaccine hesitancy. Vaccines are associated with local adverse reactions, such as pain and redness. Thimerosal is currently used only in multidose vials of influenza vaccine; exposure to thimerosal through vaccines is not associated with adverse neurologic outcomes. The measles-mumps-rubella vaccine is not associated with autism spectrum disorder. The respiratory syncytial virus vaccine does not increase the risk of stillbirth, infant death, birth defects, or growth restriction when administered during pregnancy. COVID-19 vaccine minimally increases the risk of myocarditis and pericarditis. Physicians should counsel patients and guide them to credible resources if patients are considering vaccine refusal. The Vaccine Adverse Event Reporting System and National Vaccine Injury Compensation Program track adverse events from vaccines; the National Vaccine Injury Compensation Program provides compensation for documented harms from vaccinations.

SARAH COLES, MD, FAAFP, is a program director at the Colorado Plateau Center for Health Professions Family and Community Medicine Residency at North Country HealthCare and an associate professor of Family, Community, and Preventive Medicine at the University of Arizona College of Medicine – Phoenix. See Editor's Note.

Published online March 16, 2026.

Address correspondence to Sarah Coles, MD, FAAFP, at swhitley@arizona.edu.

Author disclosure: No relevant financial relationships.

  1. 1.Shattock AJ, Johnson HC, Sim SY, et al. Contribution of vaccination to improved survival and health: modelling 50 years of the Expanded Programme on Immunization. Lancet. 2024;403(10441):2307-2316.
  2. 2.Zhou F, Jatlaoui TC, Leidner AJ, et al. Health and economic benefits of routine childhood immunizations in the era of the Vaccines for Children Program—United States, 1994–2023. MMWR Morb Mortal Wkly Rep. 2024;73(31):682-685.
  3. 3.Seither R, Yusuf OB, Dramann D, et al. Coverage with selected vaccines and exemption rates among children in kindergarten— United States, 2023–24 school year. MMWR Morb Mortal Wkly Rep. 2024;73(41):925-932.
  4. 4.Hung MC, Srivastav A, Lu PJ, et al. Vaccination coverage among adults in the United States, National Health Interview Survey, 2022. October 4, 2024. Accessed February 15, 2026. https://www.cdc.gov/adultvaxview/publications-resources/adult-vaccination-coverage-2022.html
  5. 5.Ruggeri K, Vanderslott S, Yamada Y, et al. Behavioural interventions to reduce vaccine hesitancy driven by misinformation on social media. BMJ. 2024;384:e076542.
  6. 6.Whitehead HS, French CE, Caldwell DM, et al. A systematic review of communication interventions for countering vaccine misinformation. Vaccine. 2023;41(5):1018-1034.
  7. 7.Chung Y, Schamel J, Fisher A, et al. Influences on immunization decision-making among US parents of young children. Matern Child Health J. 2017;21(12):2178-2187.
  8. 8.Glanz JM, Wagner NM, Narwaney KJ, et al. A mixed methods study of parental vaccine decision making and parent-provider trust. Acad Pediatr. 2013;13(5):481-488.
  9. 9.Townes A, Shaughnessy AF. Vaccine conversations: meeting patients where they are [Curbside Consultation]. Am Fam Physician. 2026;113(4):396-397.
  10. 10.Centers for Disease Control and Prevention. Epidemiology and Prevention of Vaccine-Preventable Diseases. 14th ed. Public Health Foundation; 2021.
  11. 11.Pillai Riddell RR, Bucsea O, Shiff I, et al. Non-pharmacological management of infant and young child procedural pain. Cochrane Database Syst Rev. 2023(6):CD006275.
  12. 12.Shah PS, Torgalkar R, Shah VS. Breastfeeding or breast milk for procedural pain in neonates. Cochrane Database Syst Rev. 2023(8):CD004950.
  13. 13.Hatfield LA, Gusic ME, Dyer AM, et al. Analgesic properties of oral sucrose during routine immunizations at 2 and 4 months of age. Pediatrics. 2008;121(2):e327-e334.
  14. 14.Birnie KA, Noel M, Chambers CT, et al. Psychological interventions for needle-related procedural pain and distress in children and adolescents. Cochrane Database Syst Rev. 2018(10):CD005179.
  15. 15.Beirne PV, Hennessy S, Cadogan SL, et al. Needle size for vaccination procedures in children and adolescents. Cochrane Database Syst Rev. 2018(8):CD010720.
  16. 16.Rennels MB. Extensive swelling reactions occurring after booster doses of diphtheria-tetanus-acellular pertussis vaccines. Semin Pediatr Infect Dis. 2003;14(3):196-198.
  17. 17.Saleh E, Moody MA, Walter EB. Effect of antipyretic analgesics on immune responses to vaccination. Hum Vaccin Immunother. 2016;12(9):2391-2402.
  18. 18.Rosenbloom E, Finkelstein Y, Adams-Webber T, et al. Do antipyretics prevent the recurrence of febrile seizures in children? A systematic review of randomized controlled trials and meta-analysis. Eur J Paediatr Neurol. 2013;17(6):585-588.
  19. 19.Institute for Vaccine Safety. Excipients in routinely recommended vaccines. Updated December 8, 2025. Accessed February 15, 2026. https://www.vaccinesafety.edu/components-excipients/
  20. 20.Di Pietrantonj C, Rivetti A, Marchione P, et al. Vaccines for measles, mumps, rubella, and varicella in children. Cochrane Database Syst Rev. 2021(11):CD004407.
  21. 21.Yih WK, Lieu TA, Kulldorff M, et al. Intussusception risk after rotavirus vaccination in U.S. infants. N Engl J Med. 2014;370(6):503-512.
  22. 22.Gidengil C, Goetz MB, Newberry S, et al. Safety of vaccines used for routine immunization in the United States: an updated systematic review and meta-analysis. Vaccine. 2021;39(28):3696-3716.
  23. 23.Centers for Disease Control and Prevention. Preliminary results: surveillance for Guillain-Barré syndrome after receipt of influenza A (H1N1) 2009 monovalent vaccine—United States, 2009–2010. MMWR Morb Mortal Wkly Rep. 2010;59(21):657-661.
  24. 24.Kwong JC, Vasa PP, Campitelli MA, et al. Risk of Guillain-Barré syndrome after seasonal influenza vaccination and influenza healthcare encounters: a self-controlled study. Lancet Infect Dis. 2013;13(9):769-776.
  25. 25.U.S. Food and Drug Administration. FDA requires a warning about Guillain-Barré syndrome (GBS) be included in the prescribing information for Shingrix. March 24, 2021. Accessed July 13, 2025. https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/fda-requires-warning-about-guillain-barre-syndrome-gbsbe-included-prescribing-information-shingrix
  26. 26.Kliegman RM, St. Geme JW III, eds. Nelson Textbook of Pediatrics. 22nd ed. Elsevier; 2024.
  27. 27.Scott J, Abers MS, Marwah HK, et al. Updated evidence for Covid-19, RSV, and influenza vaccines for 2025–2026. N Engl J Med. 2025;393(22):2221-2242.
  28. 28.U.S. Food and Drug Administration. Common ingredients in FDA-approved vaccines. Current March 2, 2024. Accessed March 10, 2026. https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/common-ingredients-fda-approved-vaccines
  29. 29.Andersson NW, Bech Svalgaard I, Hoffmann SS, et al. Aluminum-adsorbed vaccines and chronic diseases in childhood: a nationwide cohort study. Ann Intern Med. 2025;178(10):1369-1377.
  30. 30.Conklin L, Hviid A, Orenstein WA, et al. Vaccine safety issues at the turn of the 21st century. BMJ Glob Health. 2021;6(suppl 2):e004898.
  31. 31.Su JR, Moro PL, Ng CS, et al. Anaphylaxis after vaccination reported to the Vaccine Adverse Event Reporting System, 1990–2016. J Allergy Clin Immunol. 2019;143(4):1465-1473.
  32. 32.Grohskopf LA, Ferdinands JM, Blanton LH, et al. Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices—United States, 2024–25 influenza season. MMWR Recomm Rep. 2024;73(5):1-25.
  33. 33.Centers for Disease Control and Prevention. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE): safety of influenza vaccines for persons with egg allergy. August 20, 2024. Accessed July 13, 2025. https://www.cdc.gov/vaccines/acip/recs/grade/influenza-egg-allergy.html
  34. 34.Kroger A, Atkinson W, Pickering L. General immunization practices. In: Plotkin SA, Orenstein WA, Offit PA, eds. Vaccines. 6th ed. Elsevier Saunders; 2013: 88–111.
  35. 35.Committee on the Assessment of Studies of Health Outcomes Related to the Recommended Childhood Immunization Schedule; Board on Population Health and Public Health Practice; Institute of Medicine. The Childhood Immunization Schedule and Safety: Stakeholder Concerns, Scientific Evidence, and Future Studies. National Academies Press; 2013.
  36. 36.U.S. Food and Drug Administration. Thimerosal and vaccines. Updated January 15, 2025. Accessed July 13, 2025. https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/thimerosal-and-vaccines
  37. 37.Department of Health and Human Services. HHS adopts ACIP recommendation to remove thimerosal from all U.S. influenza vaccines. July 23, 2025. Accessed February 15, 2026. https://www.hhs.gov/press-room/thimerosal-mercury-removed-from-us-fluvaccines-acip.html
  38. 38.Price CS, Thompson WW, Goodson B, et al. Prenatal and infant exposure to thimerosal from vaccines and immunoglobulins and risk of autism. Pediatrics. 2010;126(4):656-664.
  39. 39.Thompson WW, Price C, Goodson B, et al.; Vaccine Safety Datalink Team. Early thimerosal exposure and neuropsychological outcomes at 7 to 10 years. N Engl J Med. 2007;357(13):1281-1292.
  40. 40.Godlee F, Smith J, Marcovitch H. Wakefield’s article linking MMR vaccine and autism was fraudulent [editorial]. BMJ. 2011;342 :c7452.
  41. 41.Centers for Disease Contral and Prevention. Measles cases and outbreaks. Updated March 6, 2026. Accessed March 10, 2026. https://www.cdc.gov/measles/data-research/index.html
  42. 42.France EK, Glanz J, Xu S, et al.; Vaccine Safety Datalink Team. Risk of immune thrombocytopenic purpura after measles-mumps-rubella immunization in children. Pediatrics. 2008;121(3):e687-e692.
  43. 43.Centers for Disease Control and Prevention. DTaP (diphtheria, tetanus, pertussis) vaccine VIS. August 6, 2021. Accessed July 13, 2025. https://www.cdc.gov/vaccines/hcp/current-vis/dtap.html
  44. 44.Centers for Disease Control and Prevention. Mumps cases and outbreaks. Updated March 1, 2026. Accessed March 10, 2026. https://www.cdc.gov/mumps/outbreaks/index.html
  45. 45.American Academy of Family Physicians. Immunization schedules; 2025. Accessed October 20, 2025. https://www.aafp.org/family-physician/patient-care/prevention-wellness/immunizationsvaccines/immunization-schedules.html
  46. 46.Jensen JE, Becker GL, Jackson JB, et al. Human papillomavirus and associated cancers: a review. Viruses. 2024;16(5):680.
  47. 47.FUTURE II Study Group. Quadrivalent vaccine against human papilloma virus to prevent high-grade cervical lesions. N Engl J Med. 2007;356(19):1915-1927.
  48. 48.Mao C, Koutsky LA, Ault KA, et al. Efficacy of human papillo ma virus-16 vaccine to prevent cervical intraepithelial neoplasia: a randomized controlled trial. Obstet Gynecol. 2006;107(1):18-27.
  49. 49.Phillips A, Hickie M, Totterdell J, et al. Adverse events following HPV vaccination: 11 years of surveillance in Australia. Vaccine. 2020;38(38):6038-6046.
  50. 50.Brouwer AF, Delinger RL, Eisenberg MC, et al. HPV vaccination has not increased sexual activity or accelerated sexual debut in a college-aged cohort of men and women. BMC Public Health. 2019;19(1):821.
  51. 51.Murphy TV, Gargiullo PM, Massoudi MS, et al. Intussusception among infants given an oral rotavirus vaccine. N Engl J Med. 2001;344(8):564-572.
  52. 52.Mbaeyi SA, Bozio CH, Duffy J, et al. Meningococcal vaccination: recommendations of the Advisory Committee on Immunization Practices, United States, 2020. MMWR Recomm Rep. 2020;69(9):1-41.
  53. 53.Schmader KE, Liu CK, Harrington T, et al. Safety, reactogenicity, and health-related quality of life after trivalent adjuvanted vs trivalent high-dose inactivated influenza vaccines in older adults: a randomized clinical trial. JAMA Netw Open. 2021;4(1):e2031266.
  54. 54.Baxter R, Patriarca PA, Ensor K, et al. Evaluation of the safety, reactogenicity and immunogenicity of FluBlok® trivalent recombinant baculovirus-expressed hemagglutinin influenza vaccine administered intramuscularly to healthy adults 50–64 years of age. Vaccine. 2011;29(12):2272-2278.
  55. 55.Volling C, Coleman BL, Katz K, et al. Immunogenicity and reactogenicity of high- vs. standard-dose trivalent inactivated influenza vaccine in healthcare workers: a pilot randomized controlled trial. Clin Microbiol Infect. 2019;25(2):217-224.
  56. 56.Sanz Fadrique R, Martín Arias L, Molina-Guarneros JA, et al. Guillain-Barré syndrome and influenza vaccines: current evidence. Rev Esp Quimioter. 2019;32(4):288-295.
  57. 57.Link-Gelles R, Chickery S, Webber A, et al.; CDC COVID-19 Vaccine Effectiveness Collaborators. Interim estimates of 2024–2025 COVID-19 vaccine effectiveness among adults aged ≥18 years—VISION and IVY Networks, September 2024–January 2025. MMWR Morb Mortal Wkly Rep. 2025;74(6):73-82.
  58. 58.Panagiotakopoulos L, Moulia DL, Godfrey M, et al. Use of COVID-19 vaccines for persons aged ≥ 6 months: recommendations of the Advisory Committee on Immunization Practices—United States, 2024–2025. MMWR Morb Mortal Wkly Rep. 2024;73(37):819-824.
  59. 59.Wiegand RE, Devine O, Wallace M, et al. Estimating COVID-19 associated hospitalizations, ICU admissions, and in-hospital deaths averted in the United States by 2023–2024 COVID-19 vaccination: a conditional probability, causal inference, and multiplier-based approach. Vaccine. 2025;49:126808.
  60. 60.Graña C, Ghosn L, Evrenoglou T, et al. Efficacy and safety of COVID-19 vaccines. Cochrane Database Syst Rev. 2022(12):CD015477.
  61. 61.Rafati A, Pasebani Y, Jameie M, et al. Association of SARS-CoV-2 vaccination or infection with Bell palsy: a systematic review and meta-analysis. JAMA Otolaryngol Head Neck Surg. 2023;149(6):493-504.
  62. 62.Fell DB, Dimanlig-Cruz S, Regan AK, et al. Risk of preterm birth, small for gestational age at birth, and stillbirth after covid-19 vaccination during pregnancy: population based retrospective cohort study. BMJ. 2022;378:e071416.
  63. 63.Goldshtein I, Steinberg DM, Kuint J, et al. Association of BNT162b2 COVID-19 vaccination during pregnancy with neonatal and early infant outcomes. JAMA Pediatr. 2022;176(5):470-477.
  64. 64.Rottenstreich M, Sela HY, Rotem R, et al. Covid-19 vaccination during the third trimester of pregnancy: rate of vaccination and maternal and neonatal outcomes, a multicentre retrospective cohort study. BJOG. 2022;129(2):248-255.
  65. 65.Fairweather D, Beetler DJ, Di Florio DN, et al. COVID-19, myocarditis and pericarditis. Circ Res. 2023;132(10):1302-1319.
  66. 66.Centers for Disease Control and Prevention; Advisory Committee on Immunization Practices. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE): updated COVID-19 vaccine (2024–2025 formulation). September 12, 2024. Accessed July 13, 2025. https://www.cdc.gov/acip/grade/covid-19-2024-2025-6-months-and-older.html
  67. 67.Centers for Disease Control and Prevention. Surveillance and data analytics. September 5, 2025. Accessed February 15, 2026. https://www.cdc.gov/covid/php/surveillance/index.html
  68. 68.Maiese A, Baronti A, Manetti AC, et al. Death after the administration of COVID-19 vaccines approved by EMA: has a causal relationship been demonstrated? Vaccines (Basel). 2022;10(2):308.
  69. 69.World Health Organization. Post COVID-19 condition (long COVID). February 26, 2025. Accessed July 13, 2025. https://www.who.int/news-room/fact-sheets/detail/post-covid-19-condition-(long-covid)
  70. 70.Byambasuren O, Stehlik P, Clark J, et al. Effect of covid-19 vaccination on long covid: systematic review. BMJ Med. 2023;2(1):e000385.
  71. 71.U.S. Food and Drug Administration. FDA approves required updated warning in labeling of mRNA COVID-19 vaccines regarding myocarditis and pericarditis following vaccination. June 25, 2025. Accessed December 17, 2025. https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/fda-approves-required-updated-warning-labeling-mrna-covid-19-vaccines-regarding-myocarditis-and
  72. 72.Husby A, Gulseth HL, Hovi P, et al. Clinical outcomes of myocarditis after SARS-CoV-2 mRNA vaccination in four Nordic countries: population based cohort study. BMJ Med. 2023;2(1):e000373.
  73. 73.Papi A, Ison MG, Langley JM, et al.; AReSVi-006 Study Group. Respiratory syncytial virus prefusion F protein vaccine in older adults. N Engl J Med. 2023;388(7):595-608.
  74. 74.Melgar M, Britton A, Roper LE, et al. Use of respiratory syncytial virus vaccines in older adults: recommendations of the Advisory Committee on Immunization Practices—United States, 2023. MMWR Morb Mortal Wkly Rep. 2023;72(29):793-801.
  75. 75.Lassen MCH, Johansen ND, Christensen SH, et al. Bivalent RSV prefusion F protein–based vaccine for preventing cardiovascular hospitalizations in older adults: a prespecified analysis of the DANRSV trial. JAMA. 2025;334(16):1431-1441.
  76. 76.Anderer S. FDA issues warning of Guillain-Barré syndrome risk for 2 RSV vaccines. JAMA. 2025;333(12):1023-1024.
  77. 77.Wilson E, Goswami J, Baqui AH, et al.; ConquerRSV Study Group. Efficacy and safety of an mRNA-based RSV PreF vaccine in older adults. N Engl J Med. 2023;389(24):2233-2244.
  78. 78.Phijffer EW, de Bruin O, Ahmadizar F, et al. Respiratory syncytial virus vaccination during pregnancy for improving infant outcomes. Cochrane Database Syst Rev. 2024(5):CD015134.
  79. 79.Drysdale SB, Cathie K, Flamein F, et al.; HARMONIE Study Group. Nirsevimab for prevention of hospitalizations due to RSV in infants. N Engl J Med. 2023;389(26):2425-2435.
  80. 80.Sun M, Lai H, Na F, et al. Monoclonal antibody for the prevention of respiratory syncytial virus in infants and children: a systematic review and network meta-analysis. JAMA Netw Open. 2023;6(2):e230023.
  81. 81.US Food and Drug Administration. Beyfortus (nirsevimab-alip) injection, for intramuscular use [package insert]. Accessed February 15, 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/761328s000lbl.pdf
  82. 82.Merck. Enflonsia (clesrovimab-cfor) injection, for intramuscular use [package insert]. Accessed February 15, 2026. https://www.merck.com/product/usa/pi_circulars/e/enflonsia/enflonsia_pi.pdf
  83. 83.Hesse EM, Shimabukuro TT, Su JR, et al. Postlicensure safety surveillance of recombinant zoster vaccine (Shingrix)—United States, October 2017–June 2018. MMWR Morb Mortal Wkly Rep. 2019;68(4):91-94.
  84. 84.Ascherio A, Zhang SM, Hernán MA, et al. Hepatitis B vaccination and the risk of multiple sclerosis. N Engl J Med. 2001;344(5):327-332.
  85. 85.Centers for Infectious Disease Research and Policy. Universal hepatitis B vaccination at birth: safety, effectiveness, and public health impact. December 2, 2025. Accessed December 3, 2025. https://www.cidrap.umn.edu/sites/default/files/searchable-download/Universal%20Hepatitis%20B%20Vaccination%20at%20Birth%202Dec2025.pdf
  86. 86.American Academy of Pediatrics. AAP immunization schedule. February 5, 2026. Accessed February 15, 2026. https://publications.aap.org/redbook/resources/pdfDownload/15585
  87. 87.Centers for Disease Control and Prevention. Submitting a Vaccine Adverse Event Reporting System (VAERS) report and using VAERS data. May 7, 2025. Accessed July 13, 2025. https://www.cdc.gov/vaccine-safety-systems/vaers/access-use.html
  88. 88.Centers for Disease Control and Prevention. About the Vaccine Safety Datalink (VSD). September 12, 2025. Accessed February 15, 2026. https://www.cdc.gov/vaccine-safety-systems/vsd/?ref=blog.omnimaker.io
  89. 89.Centers for Disease Control and Prevention. About V-safe. September 7, 2025. Accessed February 15, 2026. https://www.cdc.gov/vaccine-safety-systems/v-safe/index.html
  90. 90.Spencer JP, Pawlowski RHT, Thomas S. Vaccine adverse events: separating myth from reality. Am Fam Physician. 2017;95(12):786-794.
  91. 91.Kimmel SR. Vaccine adverse events: separating myth from reality. Am Fam Physician. 2002;66(11):2113-2121.
Previous article
Thrombocytosis: Rapid Evidence Review
Apr 2026
Next article
Systemic Sclerosis: Evaluation and Treatment

Current issue

May 2026

May 2026

Copyright © 2026 by the American Academy of Family Physicians.

This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. See permissions for copyright questions and/or permission requests.