Long Term Immunogenicity of the Hepatitis B Vaccine in 9 year-old School Children: A Five-Year Followup

[Guest guest]

Long Term Immunogenicity of the Hepatitis B Vaccine in 9 year-old School

Children: A Five-Year Follow-up

B. Duvall, N.Boulianne, G.De Serres, P. De Wals, R. Masse, G. Trudeau,

V.Gilca

Introduction:

The long-term duration of the protection conferred by the hepatitis B

vaccine in children is a very important question since most exposures will

occur many years after the primary immunization. We follow a cohort of 1109

nine year-old schoolchildren to measure the protection remaining 5, 10 and

15 years after the primary immunization. The results of the first phase of

the study after a 5 year follow-up are presented.

Methods:

The cohort was initiated in 1996. The participants had all reached the

seroprotective titer of 10m IU/ml after the primary immunization with a GMT

of 7307 mIU/ml. After 5 years, the remaining 978 subjects were randomly

allocated to three groups. Anti-HBs were measured in the 303 subjects of the

first group. A booster dose was then administered and the anti-HBs were

tested one month later.

Results:

After 5 years, 5.3% had no detectable anti-HBs and 7.3% had a titer inferior

to the protective level of 10 mIU/ml. The GMT was 252 mIU/ml. After the

booster dose, only 1 subject (0.3%) had no detectable anti-HBs and 2 more

had a titer inferior to 10 mID/mI. The GMT was 113 201 mIU/ml. All subjects

who had a detectable titer and 62.5% of those who had a titer inferior to 10

mIU/ml reached a titer superior to 100 mIU/ml after boosting.

Conclusion:

Among children who initially had reached the seroprotective level, more than

12% had no protective level of antibodies after 5 years. As expected, most

of them had a good immune response to a booster dose even when they had no

measurable antibodies. However, 1% of the children who were initially

protected did not respond to the booster dose. It remains to be seen if this

proportion will increase among the two other groups who will be tested after

respectively 10 and 15 years.

http://www.hcvadvocate.org/news/reports/International_Symposium.html

[Guest guest]

Long Term Immunogenicity of the Hepatitis B Vaccine in 9 year-old School

Children: A Five-Year Follow-up

B. Duvall, N.Boulianne, G.De Serres, P. De Wals, R. Masse, G. Trudeau,

V.Gilca

Introduction:

The long-term duration of the protection conferred by the hepatitis B

vaccine in children is a very important question since most exposures will

occur many years after the primary immunization. We follow a cohort of 1109

nine year-old schoolchildren to measure the protection remaining 5, 10 and

15 years after the primary immunization. The results of the first phase of

the study after a 5 year follow-up are presented.

Methods:

The cohort was initiated in 1996. The participants had all reached the

seroprotective titer of 10m IU/ml after the primary immunization with a GMT

of 7307 mIU/ml. After 5 years, the remaining 978 subjects were randomly

allocated to three groups. Anti-HBs were measured in the 303 subjects of the

first group. A booster dose was then administered and the anti-HBs were

tested one month later.

Results:

After 5 years, 5.3% had no detectable anti-HBs and 7.3% had a titer inferior

to the protective level of 10 mIU/ml. The GMT was 252 mIU/ml. After the

booster dose, only 1 subject (0.3%) had no detectable anti-HBs and 2 more

had a titer inferior to 10 mID/mI. The GMT was 113 201 mIU/ml. All subjects

who had a detectable titer and 62.5% of those who had a titer inferior to 10

mIU/ml reached a titer superior to 100 mIU/ml after boosting.

Conclusion:

Among children who initially had reached the seroprotective level, more than

12% had no protective level of antibodies after 5 years. As expected, most

of them had a good immune response to a booster dose even when they had no

measurable antibodies. However, 1% of the children who were initially

protected did not respond to the booster dose. It remains to be seen if this

proportion will increase among the two other groups who will be tested after

respectively 10 and 15 years.

http://www.hcvadvocate.org/news/reports/International_Symposium.html

[Guest guest]

Long Term Immunogenicity of the Hepatitis B Vaccine in 9 year-old School

Children: A Five-Year Follow-up

B. Duvall, N.Boulianne, G.De Serres, P. De Wals, R. Masse, G. Trudeau,

V.Gilca

Introduction:

The long-term duration of the protection conferred by the hepatitis B

vaccine in children is a very important question since most exposures will

occur many years after the primary immunization. We follow a cohort of 1109

nine year-old schoolchildren to measure the protection remaining 5, 10 and

15 years after the primary immunization. The results of the first phase of

the study after a 5 year follow-up are presented.

Methods:

The cohort was initiated in 1996. The participants had all reached the

seroprotective titer of 10m IU/ml after the primary immunization with a GMT

of 7307 mIU/ml. After 5 years, the remaining 978 subjects were randomly

allocated to three groups. Anti-HBs were measured in the 303 subjects of the

first group. A booster dose was then administered and the anti-HBs were

tested one month later.

Results:

After 5 years, 5.3% had no detectable anti-HBs and 7.3% had a titer inferior

to the protective level of 10 mIU/ml. The GMT was 252 mIU/ml. After the

booster dose, only 1 subject (0.3%) had no detectable anti-HBs and 2 more

had a titer inferior to 10 mID/mI. The GMT was 113 201 mIU/ml. All subjects

who had a detectable titer and 62.5% of those who had a titer inferior to 10

mIU/ml reached a titer superior to 100 mIU/ml after boosting.

Conclusion:

Among children who initially had reached the seroprotective level, more than

12% had no protective level of antibodies after 5 years. As expected, most

of them had a good immune response to a booster dose even when they had no

measurable antibodies. However, 1% of the children who were initially

protected did not respond to the booster dose. It remains to be seen if this

proportion will increase among the two other groups who will be tested after

respectively 10 and 15 years.

http://www.hcvadvocate.org/news/reports/International_Symposium.html

[Guest guest]

Long Term Immunogenicity of the Hepatitis B Vaccine in 9 year-old School

Children: A Five-Year Follow-up

B. Duvall, N.Boulianne, G.De Serres, P. De Wals, R. Masse, G. Trudeau,

V.Gilca

Introduction:

The long-term duration of the protection conferred by the hepatitis B

vaccine in children is a very important question since most exposures will

occur many years after the primary immunization. We follow a cohort of 1109

nine year-old schoolchildren to measure the protection remaining 5, 10 and

15 years after the primary immunization. The results of the first phase of

the study after a 5 year follow-up are presented.

Methods:

The cohort was initiated in 1996. The participants had all reached the

seroprotective titer of 10m IU/ml after the primary immunization with a GMT

of 7307 mIU/ml. After 5 years, the remaining 978 subjects were randomly

allocated to three groups. Anti-HBs were measured in the 303 subjects of the

first group. A booster dose was then administered and the anti-HBs were

tested one month later.

Results:

After 5 years, 5.3% had no detectable anti-HBs and 7.3% had a titer inferior

to the protective level of 10 mIU/ml. The GMT was 252 mIU/ml. After the

booster dose, only 1 subject (0.3%) had no detectable anti-HBs and 2 more

had a titer inferior to 10 mID/mI. The GMT was 113 201 mIU/ml. All subjects

who had a detectable titer and 62.5% of those who had a titer inferior to 10

mIU/ml reached a titer superior to 100 mIU/ml after boosting.

Conclusion:

Among children who initially had reached the seroprotective level, more than

12% had no protective level of antibodies after 5 years. As expected, most

of them had a good immune response to a booster dose even when they had no

measurable antibodies. However, 1% of the children who were initially

protected did not respond to the booster dose. It remains to be seen if this

proportion will increase among the two other groups who will be tested after

respectively 10 and 15 years.

http://www.hcvadvocate.org/news/reports/International_Symposium.html