Vaccination strategies against hepatitis A in travelers older than 40 years: an economic evaluation.
BACKGROUND
In recent years, the number of travelers aged >40 years who acquire hepatitis A while traveling has increased. Therefore, there is a need to review hepatitis A vaccination protocols in travelers. The aims of the study were to assess immunity levels to hepatitis A virus (HAV) in international travelers >40 years and to determine the least costly immunization strategy.


METHODS
A serological examination of HAV antibodies in 427 international travelers aged >40 years traveling endemic zones was carried out. The prevalence of antibodies in each age group was assessed. The costs of two preventive strategies, direct vaccination of all subjects (independent of the immune status) or screening and subsequent vaccination of susceptible subjects were compared. The critical value of prevalence (CVP) (the value at which the costs for the two strategies are equal) was calculated.


RESULTS
Total prevalence of HAV antibodies was 78.9% [95% confidence interval (CI): 74.8-82.5] and was 80.0% (95% CI: 73.8-85.2) in men and 77.9% (95% CI: 71.9-83.2) in women. There was a positive association with age. In the 40 to 49, 50 to 59, 60 to 69, and 70 to 95 years age groups, the prevalence rates were 62.6 (95% CI: 53.8-71.5), 76.8 (95% CI: 70.0-82.7), 91.7 (95% CI: 85.2-95.6), and 97.5% (95% CI: 87.4-99.6), respectively. The CVP was 58.4% using two doses of vaccine.


CONCLUSIONS
The CVP was lower than the prevalence rate found in our international travelers. Therefore, we recommend systematic screening for HAV antibodies before selective vaccination of international travelers aged >40 years traveling to hepatitis A endemic zones.
Preventive Medicine and Epidemiology Department, Hospital Clinic/IDIBAPS, Barcelona, Spain. lcostas@clinic.ub.es
Laura
L
Costas
Anna
A
Vilella
Antoni
A
Trilla
Beatriz
B
Serrano
Isabel
I
Vera
Montse
M
Roldán
Maria-Pilar
MP
Sancho
Jose-Maria
JM
Bayas
Joaquim
J
Gascón
Josep
J
Costa
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003663:Decision Trees; D005260:Female; D006506:Hepatitis A / Q000097:blood / Q000191:economics* / Q000453:epidemiology / Q000517:prevention & control*; D035922:Hepatitis A Antibodies / Q000097:blood*; D022362:Hepatitis A Vaccines / Q000191:economics*; D017957:Hepatitis A Virus, Human / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D013030:Spain / Q000453:epidemiology; D014195:Travel
D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines