Evaluation of hepatitis B vaccine immunogenicity among older adults during an outbreak response in assisted living facilities.
BACKGROUND
During the past decade, in the United States, an increasing number of hepatitis B outbreaks have been reported in assisted living facilities (ALFs) as a result of breaches in infection control practices. We evaluated the seroprotection rates conferred by hepatitis B vaccine among older adults during a response to an outbreak that occurred in multiple ALFs and assessed the influence of demographic and clinical factors on vaccine response.


METHODS
Residents were screened for hepatitis B and C infection prior to vaccination and susceptible residents were vaccinated against hepatitis B with one dose of 20 μg Engerix-B™ (GSK) given at 0, 1, and 4 months. Blood samples were collected 80-90 days after the third vaccine dose to test for anti-HBs levels.


RESULTS
Of the 48 residents who had post-vaccination blood specimens collected after the third vaccine dose, 16 (33.3%) achieved anti-HBs concentration ≥10 mIU/mL. Age was a significant determinant of seroprotection with rates decreasing from 88% among persons aged ≤60 years to 12% among persons aged ≥90 years (p=0.001). Geometric mean concentrations were higher among non-diabetic than diabetic residents, however, the difference was not statistically significant (5.1 vs. 3.8 mIU/mL, p=0.7).


CONCLUSIONS
These findings highlight that hepatitis B vaccination is of limited effectiveness when administered to older adults. Improvements in infection control and vaccination at earlier ages might be necessary to prevent spread of infection in ALFs.
Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. rtohme@cdc.gov
Rania A
RA
Tohme
Debo
D
Awosika-Olumo
Carrie
C
Nielsen
Salma
S
Khuwaja
Jennifer
J
Scott
Jian
J
Xing
Jan
J
Drobeniuc
Dale J
DJ
Hu
Cynthia
C
Turner
Toni
T
Wafeeg
Umid
U
Sharapov
Philip R
PR
Spradling
D000368:Aged; D000369:Aged, 80 and over; D040561:Assisted Living Facilities; D004196:Disease Outbreaks / Q000517:prevention & control*; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology
C075654:Engerix-B; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; D014614:Vaccines, Synthetic