Kathryn Bright, Australia

Murdoch Children's Research Institute Department of Infection and Immunity

Presenter of 1 Presentation

PROGRESS IN THE RANDOMISED CONTROLLED TRIAL "TRIAL OF SIMPLIFIED PNEUMOCOCCAL VACCINATION IN VIETNAM II: THE HERD IMMUNITY APPROACH". (ID 864)

Author Of 9 Presentations

DISEASE FEATURES OF VIETNAMMESE INFANTS FROM HOSPITAL ADMISSIONS OF A PNEUMOCOCCAL VACCINE PHASE 3 CLINICAL TRIAL (ID 741)

STUDY PARTICIPANT WITHDRAWALS: LESSONS LEARNT FROM A VACCINE TRIAL IN INFANTS IN HO CHI MINH CITY, VIETNAM (ID 1105)

Abstract

Background

Subject recruitment and retention are crucial factors contributing to the success of clinical trials. We describe the experience from a clinical trial of
pneumococcal conjugate vaccines currently underway in Ho Chi Minh City.

Methods

Subject recruitment and retention are crucial factors contributing to the success of clinical trials. We describe the experience from a clinical trial of
pneumococcal conjugate vaccines currently underway in Ho Chi Minh City.

Results

2,501 subjects were recruited at 2 months of age. To date 1,612 subjects have completed their final 24 month visit. The last 24 month visit is due in May 2020. We have a current withdrawal rate of 7.8%. The most common reason for withdrawal is moving outside the study area. Withdrawal rates and reasons by study group will be presented at the conference

Conclusions

Recruiting subjects who intend to remain in the study area is a challenge for clinical trials involving follow up of children over a number of years. Involving staff from subjects' local health clinics helps to keep the withdrawal rate down.

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PROGRESS IN THE RANDOMISED CONTROLLED TRIAL "TRIAL OF SIMPLIFIED PNEUMOCOCCAL VACCINATION IN VIETNAM II: THE HERD IMMUNITY APPROACH". (ID 864)

IMPACT OF A SINGLE DOSE OF PCV10 OR PCV13 ON NASOPHARYNGEAL PNEUMOCOCCAL CARRIAGE IN VIETNAMESE CHILDREN DURING THE FIRST YEAR OF LIFE (ID 696)

Abstract

Background

Reduced-dose schedules of pneumococcal conjugate vaccine (PCV) could increase the accessibility and use of PCV in low and middle-income countries.

Methods

Groups within the Vietnam Pneumococcal Trial II receive PCV10 and PCV13 in a 1+1 schedule at 2 and 12 months of age, or no vaccine. Nasopharyngeal swabs were collected at 6 and 12 months of age to show the impact of the 2-month dose on pneumococcal carriage.

Results

Based on analysis to date of 1152 of 3200 swabs, vaccine-type carriage was low. In unvaccinated participants, PCV10 and PCV13-type carriage were 5.1% and 10.4% at 6 months, and 8.3% and 12.0% at 12 months, respectively. A dose of PCV10 transiently reduced vaccine-type carriage at 6 months of age (3/178 [1.7%] versus 18/355 [5.1%]).

Conclusions

With the exception of the PCV10 group at 6 months of age, both vaccine-type and non-vaccine-type carriage rates were similar among PCV10-vaccinated participants, PCV13-vaccinated participants and unvaccinated controls at 6 and 12 months of age. Based on preliminary data, a single dose of PCV at 2 months of age does not appear to reduce pneumococcal carriage during the first year of life in this population.

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INCREASED PCV10 IMMUNOGENICITY FOLLOWING A TWO-DOSE PRIMARY SERIES SEPARATED BY 4 MONTHS COMPARED WITH 2 MONTHS IN VIETNAMESE INFANTS (ID 963)

CO-ADMINISTRATION OF 10-VALENT PNEUMOCOCCAL CONJUGATE VACCINE AND MEASLES VACCINE DOES NOT IMPACT ON THE IMMUNOGENICITY OF MEASLES VACCINE (ID 727)

IMMUNOGENICITY OF A SINGLE DOSE OF PCV10 OR PCV13 AT 2 MONTHS OF AGE IN VIETNAM (ID 1007)

Abstract

Background

A 1+1 pneumococcal conjugate vaccine (PCV) schedule would increase its affordability for low and middle-income countries. The Vietnam Pneumococcal Trial II includes infants randomised to receive a 1+1 schedule of PCV10 or PCV13 at 2 and 12 months of age. This study measured the immunogenicity of a single dose of either PCV given at 2 months of age.

Methods

Serotype-specific IgG was measured at 3 and 12 months of age in PCV-vaccinated and unvaccinated controls using a WHO ELISA method.

Results

At 3 months, both vaccinated groups had higher antibody levels than controls for 7/10 serotypes (all except 6B, 14, 23F). The PCV10 group had higher antibody levels than the PCV13 group for 5/10 serotypes. Similar results were seen at 12 months, with higher antibody levels for all serotypes in the PCV10 group and 8/10 serotypes (all except 6V, 23F) in the PCV13 group compared with controls and higher antibody levels in the PCV10 than the PCV13 group for 7/10 serotypes.

Conclusions

A single dose of PCV in infancy is immunogenic and likely to provide some direct protection until the time of the booster dose. There may be a difference in the degree of protection offered by different PCVs.

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