Response to Rotavirus Vaccine in Infants in Ho Chi Minh City in Vietnam

Oxford University Clinical Research Unit, Vietnam818 enrolled

Overview

The primary objective is to measure the effect of host human genetics on the resulting immunological responses and long-term protection following rotavirus immunization of a study population of infants in Ho Chi Minh City, Vietnam. The secondary objectives are to assess the temporal immunological responses following rotavirus vaccination, and to investigate the role of maternally derived antibodies, and other factors that could potentially affect immunological responses following rotavirus vaccination. Also to assess infecting rotavirus genotypes in the vaccine failure cases.

This study will be an open single arm, single centre, interventional study conducted in Ho Chi Minh City, Vietnam. A sample size of 1,000 infants will be recruited to the study between 8 to 9 weeks (which is around 2 months) of age. These infants will receive two doses of the rotavirus vaccine, Rotarix with an interval of 28-37 days (or 4-5 weeks). The parents will be requested to bring the infants 2-3 days following each Rotarix vaccination to receive the standard EPI vaccinations. The infants will then be under passive and active surveillance for rotavirus-associated diarrhoea until 18 months of age. Blood samplings during pre and post vaccination and at 6, 12 and 18 month old visits will be collected.

Study Type

INTERVENTIONAL

Allocation

Purpose

PREVENTION

Masking

NONE

Enrollment

818

Conditions

Rotavirus Diarrhea

Interventions

Rotarix vaccineBIOLOGICAL

In this study, the 1st dose of Rotarix vaccine will be administered when infants are at ages between weeks 8-9 and the 2nd dose is 28-37 days after the 1st dose, which means that there is an interval of 28-37 days or 4-5 weeks between doses. A reminding call will be set at about 4 weeks after the 1st dose to remind parents to bring their children back to Hung Vuong Hospital for the 2nd dose of Rotarix to ensure the completion of the 2nd dose of Rotarix vaccine.

Eligibility

Sex: ALLMin age: 8 WeeksMax age: 9 WeeksHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Infants (both males and females) between 8 and 9 weeks (i.e. approximately 2 months) of age who are attending Hung Vuong Hospital to receive their standard EPI vaccinations. * Currently registered residents of Districts 5 (where Hung Vuong Hospital is located) or 1, 6, 8, 10, or 11 (districts that are neighbouring district 5) in Ho Chi Minh city, with no specific intention of relocating in the next 12 months. * Informed consent to be enrolled in the study and comply with study procedures, including host genetic studies. Exclusion Criteria: * Refusal of consent. * Parent/ guardian under the age of 18. * Premature (i.e. gestation period \<37 weeks). * Infants who have already been immunized with either a rotavirus vaccine or the standard 2-month EPI vaccinations. * History of hypersensitivity to any components of the vaccine or adverse vaccine event. * History of intussusception or congenital malformation of the gastrointestinal tract in the child that is likely to predispose child to intussusception. * History of severe combined immunodeficiency disease (SCID), acquired immune deficiency syndrome (AIDS) or Human immunodeficiency virus (HIV) positivity, or other known immunodeficiency syndromes that may place the child at risk during immunisation.

Outcomes

Primary Outcomes

The rotavirus vaccine failure events during the time period from recruitment to 18 months of age.

The primary endpoint is to measure the proportion of rotavirus vaccine failure events during the time period from recruitment to 18 months of age after the first dose of vaccination.

Time frame: from the recruitment to 18 months of age after the first dose of vaccination

Secondary Outcomes

Quantification of the antibody response following immunization

The temporal kinetics of rotavirus-specific antibody responses following immunization will be measured using virus-binding enzyme-linked immunosorbent assay (ELISA), which will be used to investigate the effect of host genetics, maternally transferred antibodies, and geospatial and epidemiological factors on the humoral response following vaccination.

Time frame: data collected during 7 site visits (Visit 1: Rotarix Dose 1, Visit 2: 2-3 after Visit 1, Visit 3: 28-37 days after Visit 1, Visit 4: 2-3 days after Visit 3, Visit 5: 6 months old, Visit 6: 12 months old, Visit 7: 18 months old)

Assessment of infecting rotavirus genotypes in vaccine failure cases

The rotavirus genotypes in vaccine failure cases will be assessed to investigate whether vaccine failure cases are a result of varying rotavirus genotypes.