Adaptive immune responses to booster vaccination against yellow fever virus are much reduced compared to those after primary vaccination

Sci Rep. 2017 Apr 6;7(1):662. doi: 10.1038/s41598-017-00798-1.

Abstract

Outbreaks of Yellow Fever occur regularly in endemic areas of Africa and South America frequently leading to mass vaccination campaigns straining the availability of the attenuated Yellow Fever vaccine, YF-17D. The WHO has recently decided to discontinue regular booster-vaccinations since a single vaccination is deemed to confer life-long immune protection. Here, we have examined humoral (neutralizing antibody) and cellular (CD8 and CD4 T cell) immune responses in primary and booster vaccinees (the latter spanning 8 to 36 years after primary vaccination). After primary vaccination, we observed strong cellular immune responses with T cell activation peaking ≈2 weeks and subsiding to background levels ≈ 4 weeks post-vaccination. The number of antigen-specific CD8+ T cells declined over the following years. In >90% of vaccinees, in vitro expandable T cells could still be detected >10 years post-vaccination. Although most vaccinees responded to a booster vaccination, both the humoral and cellular immune responses observed following booster vaccination were strikingly reduced compared to primary responses. This suggests that pre-existing immunity efficiently controls booster inoculums of YF-17D. In a situation with epidemic outbreaks, one could argue that a more efficient use of a limited supply of the vaccine would be to focus on primary vaccinations.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptive Immunity*
  • Adolescent
  • Adult
  • Aged
  • Animals
  • Antibodies, Viral / immunology
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / metabolism
  • CD8-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / metabolism
  • Denmark
  • Female
  • Healthy Volunteers
  • Humans
  • Immunization, Secondary*
  • Lymphocyte Activation
  • Male
  • Mice
  • Middle Aged
  • Public Health Surveillance
  • Vaccination*
  • Yellow Fever / immunology*
  • Yellow Fever / metabolism
  • Yellow Fever / prevention & control*
  • Yellow Fever Vaccine / immunology*
  • Yellow fever virus / immunology*
  • Young Adult

Substances

  • Antibodies, Viral
  • Yellow Fever Vaccine