TY - JOUR
T1 - Q fever vaccine efficacy and occupational exposure risk in Queensland, Australia
T2 - A retrospective cohort study
AU - Woldeyohannes, Solomon M.
AU - Perkins, Nigel R.
AU - Baker, Peter
AU - Gilks, Charles F.
AU - Knibbs, Luke D.
AU - Reid, Simon A.
N1 - Publisher Copyright:
© 2020
PY - 2020/9/29
Y1 - 2020/9/29
N2 - Q-VAX® is a vaccine used to prevent Q fever. Administration of the vaccine is complicated by the need to ensure, using intradermal and serological tests, that individuals have no prior immunity. Previous studies suggest that the vaccine is highly efficacious and long-lasting in adults. However, there has been no systematic follow-up of vaccine efficacy and the longevity of immunity using population-level data. We aimed to investigate the vaccine failure rate and duration of immunity in previously vaccinated individuals. We formulated a retrospective cohort study design within a linked data. We used a Q fever vaccination registry linked to Q fever notifications and hospital admissions (1991–2016) in the state of Queensland, which has Australia's highest incidence of Q fever. Q-VAX® failure was defined as occurrence of Q fever > 14 days’ after vaccination. The incidence of Q fever in vaccinated and unvaccinated individuals was 5.40 (95% CI: 3.65, 7.72) and 89.50 (95% CI: 70.50, 112.00]) per 100,000 person-years of follow-up, respectively. The hazard ratio (HR) for Q fever was 0.07 (95% CI: 0.04, 0.10) in non-immune vaccinated compared with immune unvaccinated individuals. The overall vaccine effectiveness was found to be 94.37% suggesting that Q-VAX® is highly effective at preventing Q fever. However, the greater incidence observed in unvaccinated individuals considered immune during the pre-vaccination screening may suggest that pre-vaccination screening is sub-optimal among this study population.
AB - Q-VAX® is a vaccine used to prevent Q fever. Administration of the vaccine is complicated by the need to ensure, using intradermal and serological tests, that individuals have no prior immunity. Previous studies suggest that the vaccine is highly efficacious and long-lasting in adults. However, there has been no systematic follow-up of vaccine efficacy and the longevity of immunity using population-level data. We aimed to investigate the vaccine failure rate and duration of immunity in previously vaccinated individuals. We formulated a retrospective cohort study design within a linked data. We used a Q fever vaccination registry linked to Q fever notifications and hospital admissions (1991–2016) in the state of Queensland, which has Australia's highest incidence of Q fever. Q-VAX® failure was defined as occurrence of Q fever > 14 days’ after vaccination. The incidence of Q fever in vaccinated and unvaccinated individuals was 5.40 (95% CI: 3.65, 7.72) and 89.50 (95% CI: 70.50, 112.00]) per 100,000 person-years of follow-up, respectively. The hazard ratio (HR) for Q fever was 0.07 (95% CI: 0.04, 0.10) in non-immune vaccinated compared with immune unvaccinated individuals. The overall vaccine effectiveness was found to be 94.37% suggesting that Q-VAX® is highly effective at preventing Q fever. However, the greater incidence observed in unvaccinated individuals considered immune during the pre-vaccination screening may suggest that pre-vaccination screening is sub-optimal among this study population.
KW - Demographic factors
KW - Duration of immunity
KW - Failure rate
KW - Q fever Vaccine (Q-VAX®)
UR - http://www.scopus.com/inward/record.url?scp=85089296626&partnerID=8YFLogxK
U2 - 10.1016/j.vaccine.2020.08.006
DO - 10.1016/j.vaccine.2020.08.006
M3 - Article
C2 - 32798141
AN - SCOPUS:85089296626
SN - 0264-410X
VL - 38
SP - 6578
EP - 6584
JO - Vaccine
JF - Vaccine
IS - 42
ER -
