Ignite Creation Date:
2024-05-05 @ 11:53 AM
Last Modification Date:
2024-10-26 @ 9:15 AM
Study NCT ID:
NCT00168571
Status:
COMPLETED
Last Update Posted:
2011-09-22
First Post:
2005-09-09
Brief Title:
Long-term Follow-up of Measles Antibodies
Sponsor:
Bandim Health Project
Organization:
Bandim Health Project
Study Overview
Official Title:
Long-term Follow-up of Protective Measles Antibodies in the Two-dose Study of Standard-titre Measles Vaccine in Guinea-Bissau
Status:
COMPLETED
Status Verified Date:
2006-09
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
Few data exist on long-term persistence of measles antibodies after vaccination of West African infants The data that do exist indicate that the antibody titres decline very rapidly Our data would be the first to describe the persistence of measles antibodies after two doses of measles vaccine and the study would allow us to identify unprotected children and offer them revaccination Since persistence of measles antibodies is of crucial importance to measles control the study will contribute significantly to the existing knowledge and might have important implications for future eradication programmes
Detailed Description:
Objective To determine persistence of measles antibodies among children who received either one or two doses of Edmonston-Zagreb EZ or Schwarz SW measles vaccine
Background The World Health Organization has targeted measles for eradication by the year 2010 and although measles incidence has fallen drastically in many parts of the world several factors could hinder the eradication goal
First there is no indication of improved measles immunisation coverage world wide vaccination coverage fell in all regions of the world from 1997 to 1998 except in the Western Pacific so the general measles immunisation coverage came down to 72 Very high vaccination coverage of 95 is needed to interrupt transmission of the highly contagious measles virus
Primary and secondary vaccine failure constitute another significant problem to measles control and the HIV pandemic contributes to increased vaccine failure and permits transmission of measles virus despite high rates of immunisation coverage
Sub-clinical measles has been found to contribute to measles immunity by boosting of the antibody level and with less circulation of wild measles virus secondary vaccine failure may represent a special problem in terms of waning immunity a problem which is probably more pronounced among those vaccinated early but there are still few data relevant to this problem
Thus although effective measles vaccines are available there is still a need to find the optimal way of immunising in different epidemiological settings In areas with high measles transmission early two-dose measles vaccination schedules have been recommended for prevention of measles in the age group below the normal age of vaccination and as a means of raising vaccination coverage in general We conducted such a two-dose trial with two different strains of measles vaccine in Guinea-Bissau and found that the risk of not being vaccinated was lower in the two-dose group than in the one-dose group and the relative efficacy of a two-dose versus a one-dose schedule was high among children below the normal age of vaccination Further we found that both one or two doses of the EZ vaccine resulted in 1 of the children being unprotected at 18 months of age while one or two doses of SW resulted in 3 and 9 unprotected respectively The EZ vaccine but not the SW vaccine was able to boost the antibody response significantly after revaccination at 9 months of age in children with moderate levels of antibodies
We therefore propose to study long-term persistence of measles antibodies in this cohort where we found rather striking differences in protection at 18 months of age according to vaccine strain and number of doses to find out whether the measles antibody level is maintained over time or waning immunity is a problem since this could have important implications for global measles control and elimination
Methods With 85 seroconverters in the one-dose group we would be able to detect a difference of 10 in number of non-seroconverters with a sample size of 400 children to be blood sampled in each group
Among 6900 children with an 18 months blood sample 10 loss to follow-up between 6 and 18 months of age we will include all the children who received the EZ vaccine to be blood sampled at 6-7 years of age Available are 450 samples from 18 months of age and with 20 loss to follow-up we will have a total of 360 children in this group
Among children who received the SW vaccine we plan to follow up half of the children at 6-7 years of age and the other half 3 years later at 9-10 years of age Including the first 2000 children with an 18 months blood sample we will be able to include about 1600 children in the study with 20 loss to follow-up Thus we will have 400 children in each arm of the study one dose two dose at 6-7 and at 9-10 years of age
Children with unprotective measles antibody level will be offered revaccination
Background The World Health Organization has targeted measles for eradication by the year 2010 and although measles incidence has fallen drastically in many parts of the world several factors could hinder the eradication goal
First there is no indication of improved measles immunisation coverage world wide vaccination coverage fell in all regions of the world from 1997 to 1998 except in the Western Pacific so the general measles immunisation coverage came down to 72 Very high vaccination coverage of 95 is needed to interrupt transmission of the highly contagious measles virus
Primary and secondary vaccine failure constitute another significant problem to measles control and the HIV pandemic contributes to increased vaccine failure and permits transmission of measles virus despite high rates of immunisation coverage
Sub-clinical measles has been found to contribute to measles immunity by boosting of the antibody level and with less circulation of wild measles virus secondary vaccine failure may represent a special problem in terms of waning immunity a problem which is probably more pronounced among those vaccinated early but there are still few data relevant to this problem
Thus although effective measles vaccines are available there is still a need to find the optimal way of immunising in different epidemiological settings In areas with high measles transmission early two-dose measles vaccination schedules have been recommended for prevention of measles in the age group below the normal age of vaccination and as a means of raising vaccination coverage in general We conducted such a two-dose trial with two different strains of measles vaccine in Guinea-Bissau and found that the risk of not being vaccinated was lower in the two-dose group than in the one-dose group and the relative efficacy of a two-dose versus a one-dose schedule was high among children below the normal age of vaccination Further we found that both one or two doses of the EZ vaccine resulted in 1 of the children being unprotected at 18 months of age while one or two doses of SW resulted in 3 and 9 unprotected respectively The EZ vaccine but not the SW vaccine was able to boost the antibody response significantly after revaccination at 9 months of age in children with moderate levels of antibodies
We therefore propose to study long-term persistence of measles antibodies in this cohort where we found rather striking differences in protection at 18 months of age according to vaccine strain and number of doses to find out whether the measles antibody level is maintained over time or waning immunity is a problem since this could have important implications for global measles control and elimination
Methods With 85 seroconverters in the one-dose group we would be able to detect a difference of 10 in number of non-seroconverters with a sample size of 400 children to be blood sampled in each group
Among 6900 children with an 18 months blood sample 10 loss to follow-up between 6 and 18 months of age we will include all the children who received the EZ vaccine to be blood sampled at 6-7 years of age Available are 450 samples from 18 months of age and with 20 loss to follow-up we will have a total of 360 children in this group
Among children who received the SW vaccine we plan to follow up half of the children at 6-7 years of age and the other half 3 years later at 9-10 years of age Including the first 2000 children with an 18 months blood sample we will be able to include about 1600 children in the study with 20 loss to follow-up Thus we will have 400 children in each arm of the study one dose two dose at 6-7 and at 9-10 years of age
Children with unprotective measles antibody level will be offered revaccination
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None
Secondary IDs
| Secondary ID | Type | Domain | Link |
|---|---|---|---|
| Lægevidenskabens Fremme-2292 | None | None | None |
| NOVO-2288 | None | None | None |