Evaluation of a recombinant DNA hepatitis B vaccine in a vaccinated Nigerian population.
BACKGROUND
Recombinant hepatitis B vaccine was introduced in 1986 and has gradually replaced the plasma-derived hepatitis B vaccine. No published data are available on the immunogenicity of hepatitis B vaccines in Nigerians. The current study aimed to evaluate protective sero-conversion rates after vaccination with Shanvac-B rDNA hepatitis B vaccine in Nigerian subjects between January and September 2009.


METHODS
After having obtained informed consent and ethical clearance, 2 mL of blood were aseptically collected from each participant aged ≤50 years, one month after the first, second and third doses of the vaccine. Sera were separated into cryovials and frozen at -21oC until analysed for the detection of the protective antibody titre induction. Protective antibody titre was defined as a titre of ≥10 mIU/mL.


RESULTS
Of the 376 participants, 192 (51.1%) were males and 184 (48.9%) were females. A total of 144 subjects participated in the first-dose group, nine (6.3%) of whom developed protective antibody titre (8.3% of males and 4.2% of females). Of the 121 participants in the second-dose group, 108 (89.3%) developed protective antibody titre (98.3% of males and 80.3% of females), while of the 111 participants in the third-dose group, 100% protectively sero-converted. Males were more likely to develop protective antibody titre than females after the second dose (P < 0.05).


CONCLUSIONS
This data provides additional evidence for the efficacy of Shanvac-B rDNA hepatitis B vaccine and the need to adhere to the recommended three-dose schedule to achieve full and lasting sero-protection among Nigerians.
Faculty of Natural and Applied Sciences, Nasarawa State University, Keffi, Nigeria. adogamoses@yahoo.com
Moses P
MP
Adoga
Grace
G
Pennap
Becky O
BO
Akande
Jamey P
JP
Mairiga
Simon
S
Pechulano
Simon M
SM
Agwale
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D008297:Male; D008875:Middle Aged; D009549:Nigeria; D016896:Treatment Outcome; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology; D055815:Young Adult
D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; C522543:Shanvac B; D014614:Vaccines, Synthetic