Non-interference Study of MR and Yellow Fever Vaccines Among Bangladeshi Infants Aged 9-12 Months

This is a prospective, randomized, parallel, three-arm, open-label, equivalence clinical trial of co-administration of MR vaccines (manufactured by Zydus Lifesciences Limited) and Yellow fever vaccine (WHO prequalified) among healthy infants 9 to 12 months of age in Dhaka, Bangladesh will be conducted. Infants who did not receive any of the aforementioned vaccines will be included in the study.

Hypothesis:

Seropositivity following concomitant administration of MR and Yellow fever vaccines is equivalent when the vaccines are administered alone

Specific Objectives

Primary objective:

To evaluate the immunological non-interference of co-administration of Measles and Rubella vaccine (Live) I.P. (Freeze Dried) \[MR vaccine\] of M/s. Zydus Lifesciences Ltd. with Yellow fever \[YF\] vaccine in healthy infants.

Secondary objective:

To evaluate the safety of co-administration of MR vaccine of M/s. Zydus Lifesciences Ltd. with Yellow fever vaccine in healthy infants.

Study design This will be a prospective, randomized, parallel, three-arm, open-label, equivalence clinical trial to evaluate the immunogenicity and safety of the co-administration of the MR vaccine manufactured by Zydus Lifesciences Ltd. with Yellow fever vaccine in healthy infants aged 9-12 months. The study will be conducted in a population of infants who is residing in a selected geographical catchment area in Dhaka, Bangladesh.

A minimum of 1530 healthy infants aged 9-12 months (age at enrollment, calculated as per completed months) over the study area will be enrolled in this clinical trial to evaluate the immunogenicity and safety of the study vaccines.

Study area Dakshinkhan and Uttarkhan are both located in the Dhaka North City Corporation (DNCC) with distinct population characteristics and geographical areas. Dakshinkhan spans 11 square kilometers and had a population of 416,601 in 2022, resulting in a high population density of 37,872 people per square kilometer. It contains 113,709 households, with an average household size of 3.8 individuals, and a gender distribution of 53.63% male and 46.37% female. In 2023, the birth of 8,884 new children resulted in a birth rate of 21.3 per 1,000 inhabitants. Uttarkhan is larger with an area of 20.5 square kilometers with the population density of 6,153 people per square kilometer, resulting in a total population of 126,149 as of 2022. This population is distributed across 33,901 households, with an average household size of 3.7 individuals. The gender distribution shows 51.91% male and 48.08% female. In 2023, the birth of 2,806 new children in a birth rate of 22.2 per 1,000 inhabitants.

Selection of age-eligible infants by household visit in the study area All households in the study area will be assigned a unique identification number and all household members will be enumerated. Information about the age-eligible infants including name, age, sex, date of birth, and parent's name will be obtained. In addition, the name of the HH head, address, and cell phone number of HHs will be collected. The investigators will take photos of birth certificates or national immunization cards to confirm the age of participants if available. Verbal consent will be provided by either the head of the household or a key informant.

Distribution of participant card for potentially eligible infants for vaccination After preparing the baseline list, the investigators will identify the age-eligible (9-12 months) participants. Then the investigator will prepare participant cards for all eligible infants which will be provided before the vaccination. There will be a unique identification number on the participant card which will be used during vaccination. A master list of potential eligible participants will be prepared.

Informed consent The informed written consent will be presented to the participant's parent/guardian in Bangla detailing no less than the exact nature of the study, what it will involve for the participant, the implications and constraints of the protocol, the known side effects and any risks involved in taking part. It will be clearly stated that the participant's parent/guardian is free to withdraw their child from the study at any time for any reason without prejudice to future care, without affecting their legal rights, and with no obligation to give the reason for withdrawal. The participant and their parents/guardians will be allowed as much time as they wish to consider the information, within the recruitment period, and the opportunity to question the investigator or other independent parties to decide whether they will participate in the study. Written informed consent will then be obtained using the participants' parent/guardian's dated signature or thumbprint and dated signature of the person who presented and obtained the informed consent. The person who obtained the consent must be suitably qualified and experienced and have been authorized to do so by the Principal Investigator (PI). A copy of the signed informed consent will be given to the participant's parents/guardians. The original signed form will be retained at the study site. An impartial witness for the parent/guardian will attest that the information in the consent form and any other written information was accurately explained to, and understood by the parent/guardian and that informed consent was freely given by the parent/guardian. The witness will also sign and date the consent form.

Screening and eligibility assessment Study staff will invite participants to the field office to be enrolled in the study. If agreed, written consent will be obtained from the parent/guardian at the field office. After obtaining informed written consent, the investigators will collect 4-5 ml of blood specimens at the time of screening (visit-1) to evaluate serological markers of dengue infection (NS1 antigen, IgM, and IgG antibodies) and Japanese Encephalitis (IgM and IgG antibodies). The investigators will carry out the aforementioned screening tests because previous studies showed that the prevalence of asymptomatic dengue infections during outbreaks was 59.26%. Most Japanese encephalitis infections are also asymptomatic. So, it is important to conduct screening tests to identify and exclude participants with asymptomatic infections. Additionally, there is a potential for cross-reactivity of Yellow fever antibodies with antibodies generated against other flaviviruses, such as dengue and Japanese encephalitis. Therefore, screening tests are important to exclude participants with pre-existing antibody titres. The remaining blood specimens will be used for baseline (pre-vaccination) immunological assessment. After the screening test, the potentially eligible, seronegative participants will be enrolled for vaccination within 24 hours of blood collection. They will undergo a thorough general physical examination including recording of vitals such as body temperature, heart rate, and respiratory rate. The Participants will be evaluated as per the inclusion and exclusion criteria. Vitals will be recorded and physical examination will be conducted at each follow-up visit and the end of the study visit. After screening, the eligible participant will be enrolled for vaccination in different groups after matching with eligibility criteria. A member of the study team will collect/edit demographic information (including age and address) and participant contact details in the screening case report form (CRF).

Enrollment Potential participants will attend the vaccination site. Upon arrival, inclusion/exclusion criteria will be assessed. The physical examination will be carried out before vaccination. Before vaccination, TSS will ensure that the results of screening tests are available. After completion of the eligibility checking, a sticker will be allocated for the participant which includes the information of vaccination ID and axillary temperature; these will be used in the vaccine accountability log. Based on the randomization of the three groups (mentioned below), the appropriate vaccine will be administered by a trained study staff. The participant will then be vaccinated and will be asked to wait at least 30 minutes for any immediate hypersensitivity reactions or other adverse events (AEs). All details will be recorded in the eCRF (Electronic Case Report Form).

Three Study groups A.Test (MR+YF): MR and YF vaccines administered concomitantly at day 0 B.Reference 1 (MR): MR vaccine administered at day 0 C.Reference 2 (YF): YF vaccine administered at day 0

Randomization The study statistician will prepare computer-generated randomization lists. The enrolled Participants would be assigned to one of the three study groups according to the centralized computer-generated randomization allocation.

Study activities

This study will be conducted as per the methods and procedures described in the visit-wise manner as follows:

Visit 1 / Upto Day -1 (Screening)

* Written informed consent will be taken from the parents or guardians of the participants before performing any study-related activity * A participant ID number will be assigned once the study-specific consent form has been signed * Demographic details i.e., age, and gender will be recorded * Vital signs (body temperature, heart rate, and respiratory rate) will be recorded * Medical and vaccination history will be obtained and physical examination (length, and weight) will be performed by a physician * Inclusion/exclusion criteria are reviewed to determine qualification for enrolment. * Blood specimens (4-5 ml) will be collected for Dengue NS1 antigen, IgM\& IgG antibodies and Japanese Encephalitis IgM \& IgG antibodies and baseline (pre-vaccination) anti-measles, anti-rubella IgG, and anti-YF antibody titre

Visit 2 / Day 0 (Enrollment, Randomization and Vaccination)

* Clinical evaluation and eligibility criteria will be reviewed by the study physician to evaluate the eligibility for enrollment * Medical and vaccination history will be recorded * Vital signs (body temperature, heart rate, and respiratory rate) recording and physical examination will be performed * Inclusion and exclusion criteria (as mentioned before) will be checked * Eligible participants will be enrolled * The participant will be randomized in one of the three study groups as per their allocated randomization number and the allocated study vaccine will be administered * Assessment of immediate reactions: For group A, the MR vaccine will be administered and the participants will be observed for 30 minutes to monitor for any immediate adverse or anaphylaxis reactions. Then the YF vaccine will be administered and the participants will be observed for another 30 minutes. For groups B and C, the participants will be observed for 30 minutes after each vaccination * AEs, if any (volunteered by the participants' parents or observed by the investigator/designee) during this observation period will be recorded * Two diary cards (one for solicited AEs and one for unsolicited AEs) will be provided to participants' parents/guardians to record local (injection site) and systemic AEs. Solicited local AEs will be recorded for 7 days after vaccination, solicited systemic AEs will be recorded for 14 days after vaccination and participants' parents/guardians will be instructed to bring the diary card for solicited AEs at visit 3 (Week 2+3 days). Unsolicited AEs will be recorded for 6 weeks (±3 days) after vaccination. The investigators will collect the diary card for unsolicited AEs at Visit 4 (week 6 ± 3 days). Following visit 4, unsolicited AEs will only be recorded if they are defined as serious adverse events (SAEs) or medically attended adverse events (MAAEs) for 26 weeks (±7 days)

Visit 3 / week 2 + 3 days (Follow-up):

* Vital signs recording and physical examination will be performed * Medical history including medication will be recorded * Participants' diary card for solicited AEs will be collect

• Immunogenicity [Срок оценки: 06 months]
• Safety reporting [Срок оценки: 06 months]