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Institute for Vaccine Safety

The Institute for Vaccine Safety was established in 1997 in the Department of International Health at the Johns Hopkins University School of Public Health - now the Johns Hopkins Bloomberg School of Public Health.

Our mission is to provide an independent assessment of vaccines and vaccine safety to help guide decision makers and educate physicians, the public and the media about key issues surrounding the safety of vaccines. The institute’s goal is to work toward preventing disease using the safest vaccines possible.

What's New on the IVS Website

  • COVID-19 Boosters: As of October 2021, FDA has authorized booster doses for Pfizer-BioNTech, Moderna and J&J COVID-19 vaccines. CDC recommends a single booster dose (of whichever COVID-19 vaccine is preferred) at least 6 months after a second dose of mRNA COVID-19 vaccine for people 65 years and older, and adults (18+ years) who live in long-term care settings, have underlying medical conditions, or work or live in high risk settings. CDC also recommends a single booster dose (of whichever COVID-19 vaccine is preferred) at least 2 months after an initial J&J COVID-19 vaccine for all adults (18+ years). In addition, people 18-49 years with certain underlying medical conditions and people 18-64 years at increased risk for COVID-19 exposure and transmission from occupational or institutional situations may receive a booster dose at least 6 months after their last dose, based on their individual benefits and risks. Clinical trials revealed that the rate of common local and systemic adverse events in the few weeks following each booster dose were somewhat lower than the rates following the second dose of mRNA vaccine or initial dose of J&J vaccine, respectively (with the exception of axillary swelling/tenderness being higher after the Moderna booster compared to the Moderna second dose).
  • Myocarditis/pericarditis and mRNA COVID 19 Vaccines: Myocarditis/pericarditis has been identified as a rare complcation following mRNA vaccines, primarily in adolescents and young adults. The rate is higher in males than females. The onset of symptoms is within a few days after vaccination and the pathogenesis is unknown at this time. Most patients have had mild disease with resolution within a few days to weeks. Preliminary data from several sources indicate that the incidence is greater than what might be expected by chance. CDC, the FDA and the American Adacemy of Pediatrics have concluded that the risk-benefit ratio strongly supports continuing to recommend these vaccines for everyone eligible to receive them. Read more
  • J&J/Janssen COVID-19 vaccine [update]. On Friday April 23, the ACIP had an emergency meeting to review cases of thrombosis with thrombocytopenia syndrome (TTS), a very rare syndrome in which clots occur in veins or arteries along with low platelet levels. By April 23, 15 cases of TTS had been reported in the US. These are very rare event.
       The ACIP carefully reviewed the risks and benefits of the J&J vaccine and decided to lift the pause in the use that had been made on April 13 and continue the recommendation for use of the J&J vaccine for adults older than age 18 in the US. The ACIP determined that the benefits outweighed the risks and reaffirmed the recommendations under the FDA Emergency Use Authorization (EUA).
       A warning has been added to the EUA information sheet for Health Care Providers about TTS, and in the information sheet for recipients. For those who are concerned about this vaccine, there are 2 alternative vaccines available in the United States: the Pfizer/BioNTech vaccine and the Moderna vaccine. Both of these are mRNA vaccines and have not been associated with TTS. The CDC and FDA are continuing to monitor the safety of all vaccines.
  • AstraZeneca COVID-19 Vaccine Safety [update]. Safety issues regarding blood clots following AstraZeneca COVID-19 vaccine were reviewed on April 7, 2021 by the World Health Organization (WHO), the European Medicines Agency (EMA), the UK Medicines and other Health products Regulatory Agency (MHRA).  The organizations issued statements concluding that the benefits of the vaccine outweigh the risks. There does not seem to be an increase in overall thromboembolic events but the vaccine may be associated with very rare cases of blood clots associated with thrombocytopenia. AstraZeneca COVID-19 vaccine is not currently available in the US. Link to WHO statement | link to EMA statement | link to MHRA statement (April 8, 2021)
  • Shingrix and GBS. A recent self-controlled study found an association between recombinant zoster vaccination (RZV), also known as Shingrix, and Guillain Barré Syndrome (GBS) among persons age 65 and older in the Centers for Medicare and Medicaid Services (CMS) database. The rate ratio, comparing cases in risk versus control windows, was 4.30 (95% Confidence Interval: 1.76-10.53); this corresponds to an attributable risk of 6.47 additional cases of GBS per million doses of Shingrix (95%CI: 2.47-10.47). However, these results should be interpreted with caution, as the number of cases in the study was small (13 in risk window versus 8 in control window), and the study is not yet peer reviewed. link to slides from Feb 21 ACIP Meeting
  • IVS in the News link
  • New information on COVID-19 Vaccines:
    • A page on What we know about COVID-19 Vaccines including background information, clinical trial data, safety information and links to other information. (updated 9.8.21)
    • Early reports indicate that rates of anaphylaxis following the Pfizer-BioNTech vaccine may be higher than most other vaccines. Link to early release MMWR dated Jan 6, 2021
    • A table listing components of the COVID-19 vaccines currently authorized for emergency use in the US. Anaphylaxis and other allergic reactions to these vaccines have been reported at a rate higher than for other vaccines. Polyethylene glycol is suspected as the allergen responsible for these reactions and there is cross reactivity with polysorbates which are present is some other vaccines.
  • The state of vaccine safety science: systematic review of the evidence. Dudley, et al (including other IVS faculty) update evidence assessing possible causal association of AEFIs.  Link to abstract
  • COVID-19: Information for Pediatric Healthcare Providers
    Link to CDC's information on Maintaining Childhood Immunizations During COVID-19 Pandemic
  • Prevent Shoulder Injury Associated with Vaccination (SIRVA)
    DO NOT try to identify the middle of the deltoid by using a fingerbreadth measurement from the acromion process. DO use the Australian method for identifying the middle of the deltoid injection site. Link to page
The information on this page was last updated on November 1, 2021 | © 2021 Institute for Vaccine Safety