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University Library, University of Illinois at Urbana-Champaign

COVID-19 Vaccines

Information and evidence about COVID-19 vaccine efficacy and safety

JOHNSON & JOHNSON (JENSSEN) COVID-19 VACCINE

April 23, 2021

FDA and CDC Lift Recommended Pause on Johnson & Johnson (Janssen) COVID-19 Vaccine Use Following Thorough Safety Review

Agencies Underscore Confidence in Vaccine’s Safety and Effectiveness Following Data Assessment; Available Data Suggest Potential Blood Clots Are Very Rare Events

Safety Data Summary

  • In clinical trials, side effects were common within 7 days of getting vaccinated but were mostly mild to moderate.
  • Side effects were more common in people 18–59 years old compared to people 60 years and older.
  • CDC will continue to provide updates as we learn more about the safety of the J&J/Janssen vaccine in real-world conditions.

SOURCE: CDC - https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/janssen.html (April 15, 2021)

How Well the Vaccine Works

  • The J&J/Janssen vaccine was 66.3% effective in clinical trials (efficacy) at preventing laboratory-confirmed COVID-19 illness in people who had no evidence of prior infection 2 weeks after receiving the vaccine. People had the most protection 2 weeks after getting vaccinated.
  • The vaccine had high efficacy at preventing hospitalization and death in people who did get sick. No one who got COVID-19 at least 4 weeks after receiving the J&J/Janssen vaccine had to be hospitalized.
  • Early evidence suggests that the J&J/Janssen vaccine might provide protection against asymptomatic infection, which is when a person is infected by the virus that causes COVID-19 but does not get sick.
  • CDC will continue to provide updates as we learn more about how well the J&J/Janssen vaccine works in real-world conditions.

SOURCE: CDC - https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/janssen.html (April 15, 2021)

Clinical Trial Demographic Information

Clinical trials for the J&J/Janssen vaccine included people from the following racial and ethnic categories:

  • 62.1% White
  • 17.2% Black or African American
  • 8.3% American Indian or Alaska Native
  • 5.4% Multiple races
  • 3.5% Asian
  • 0.3% Native Hawaiian or other Pacific Islander

Ethnicity:

  • 45.1% Hispanic or Latino
  • 52.4% Not Hispanic or Latino
  • 2.5% Unknown

Sex breakdown:

  • 55.5% Male
  • 44.5% Female
  • <0.1% Undifferentiated or unknown sex

Age breakdown:

  • 66.5% 18–59 years
  • 33.5% 60 years and older
    • 19.6% 65 years and older
    • 3.5% 75 years and older

SOURCE: CDC - https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/janssen.html (April 15, 2021)