Updated
April 29th, 2019

Vaccinations Seldom Cause Adverse Effects

Vaccines have an excellent safety profile overall and provide protection against infectious diseases

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A new systematic review provides a succinct summary of the scientific evidence for and/or against causal associations for 47 Adverse Events Following Immunization (AEFI). 

These reviewers said,  ‘Although vaccines currently recommended for the general population in the USA do cause some adverse reactions, vaccines have an excellent safety profile overall, and provide protection against infectious diseases. 

This review found that for 12 of the 47 AEFI studied, a causal relationship has been established with at least 1 vaccine routinely recommended to the general population in the USA. 

These 12 confirmed adverse reactions are:

  • anaphylaxis
  • arthralgia/arthritis (mild, acute and transient, not chronic)
  • deltoid bursitis (when the vaccine is administered improperly)
  • disseminated varicella infection (in immune deficient individuals for whom the varicella vaccine is contraindicated)
  • encephalitis
  • febrile seizures
  • Guillain-Barré Syndrome
  • hepatitis (in immune deficient individuals for whom the varicella vaccine is contraindicated)
  • herpes zoster
  • immune thrombocytopenic purpura
  • meningitis
  • syncope

Moreover, most of these adverse reactions are rare, said these researchers.

For the other 35 AEFIs, the evidence does not support a causal relationship with vaccines recommended for routine use in the USA. 

In particular, the evidence shows a clear lack of association between certain vaccines and AEFIs:

  • influenza vaccines do not cause asthma
  • childhood vaccines do not cause autism 
  • vaccines do not cause diabetes
  • vaccines given to immunocompetent persons does not cause hepatitis 
  • influenza vaccines do not cause MS in adults
  • DTP and hepatitis B vaccines do not cause Sudden Infant Death Syndrome

"Healthcare providers desire objective and clear information on a broad range of vaccine safety issues to assist them in answering patient questions," said Matthew Dudley, Ph.D., MSPH, one of the authors of the study.

"This review offers an update to the scientific evidence assessing possible causal associations of AEFI compiled in the 2012 report from the Institute of Medicine, and the 2014 report from the Agency for Healthcare Research and Quality, along with clear causality conclusions intended for health care providers." 

Dr. Dudley added, "Although vaccines currently recommended for the general population in the USA do cause some adverse reactions, vaccines have an excellent safety profile overall and provide protection against infectious diseases to individuals and the general population." 

The Vaccine Adverse Event Reporting System (VAERS) is a national vaccine safety surveillance program co-sponsored by the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention. 

VAERS is a program created as an outgrowth of the National Childhood Vaccine Injury Act of 1986.

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The purpose of VAERS is to detect possible signals of adverse events associated with vaccines. VAERS collects and analyzes information from reports of adverse events (possible side effects) that occur after the administration of US licensed vaccines. 

In a 2018 study, vaccines were reported to account for 19.5 percent of Adverse Drug Events (ADE) for children aged 5 years or younger. 

And, vaccine ADEs impacted only 3.7 percent for those aged 6-19 years.

Additionally, among those aged 19 years or younger, antibiotics were among the most frequent drugs associated with ADEs, led by amoxicillin at 21 percent.

Previous VAERS articles:

Recently, the World Health Organisation (WHO) said that "serious adverse events occur rarely (on the order of one per thousands to one per millions of doses), and some are so rare that risk cannot be accurately assessed." 

The WHO says “vaccine hesitancy”, which is driven partly by misinformation and online fake news, is one of the top 10 public health threats in 2019.

Dr. Dudley will present findings from "The State of Vaccine Safety Science: Systematic Reviews of the Evidence" on Monday, April 29 at 10:30 a.m. Please note that only the abstracts are being presented at the meeting. In some cases, the researchers may have additional data to share with media. 

The PAS 2019 Meeting brings together thousands of pediatricians and other health care providers to improve the health and well-being of children worldwide. For more information about the PAS 2019 Meeting, please visit here. 

Authors/Institutions: M. Dudley, N. Halsey, R. Limaye, D. Salmon, International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, UNITED STATES|S. Omer, W.A. Orenstein, Emory University, Atlanta, Georgia, UNITED STATES|S.T. O'Leary, Pediatrics, University of Colorado Anshutz Medical Campus, Aurora, Colorado, UNITED STATES. 

No conflicts of interest were disclosed. 

VAERS reports are welcome from all concerned individuals: patients, parents, healthcare providers, pharmacists, and vaccine manufacturers.