Hepatitis B Birth Dose for Newborns
Condition: Hepatitis B; Immunization; Infection
MeSH terms: Hepatitis A; Hepatitis B; Hepatitis
Study type: Interventional
Phase: Phase 4

Summary: 
      With 2.5% prevalence in general population, Pakistan is an intermediate endemicity country
      for hepatitis B. However, wide disparity exists across the country as disease prevalence in
      general population soars as high as 14% in hyper endemic areas. This hyper endemicity
      increases the risk of acquiring infection via vertical and horizontal routes of disease
      transmission. National immunization schedule in Pakistan administers the first vaccine
      against hepatitis B at 6th week after infant birth. Owing to this 6 week interlude the
      existing immunization schedule may not provide adequate protection to a newborn against the
      disease. A monovalent hepatitis B vaccination shot, administered within 12 hours of birth, is
      the preferred strategy for disease control in hyper endemic areas. The National Immunization
      Technical Advisory Groups around the world are expected to use rigorous scientific evidence
      and make changes in the immunization schedule and vaccine dosage, responding to the evolving
      epidemiology of childhood diseases. Such research on local evidence for hepatitis B vaccine
      in Pakistan is not available and our research fills this gap by This research studied the
      hepatitis B vaccine response, in two cohorts of healthy infants. An open labeled, randomized
      controlled, non-inferiority, vaccine trial methodology was used. Margin of non
      non-inferiority (Δ) was set at 5%. The trial administered hepatitis B birth dose as an
      intervention and vaccination done under the national immunization schedule was taken as
      standard of care.
    

Detailed description: 
      Study Design:

      The study is an unblinded, open-labeled, non-inferiority, randomized controlled trial with a
      participant ratio of 1:1 in each group (the design remained the same through the length of
      the study and no changes were made to the methods approved in the protocol). The reason for
      making the study as an open labeled trial is that mothers could not feasibly be blinded from
      the information on allocation scheme, and the information on vaccine given to infants could
      not be held back from family and parents. Another non-inferiority vaccine trial in Pakistan
      also used a similar approach in allocation scheme Trial Profile The trial was done at a
      tertiary care hospital in an urban area from March 15, 2015, to May 20, 2016. Assuming an
      attrition rate of 25%, the study enrolled 296 expectant mothers for allocation in two groups,
      intervention, and control group.

      Participants of the trial:

      The study population was healthy newborns born to healthy females, in a health facility.
      These pregnant women were registered for institutional deliveries at Countess Dufferin Fund
      (CDF) Hospital, Hyderabad. The CDF Hospital Hyderabad is a tertiary care hospital for women
      and children. The hospital is located in a populous downtown area of the Hyderabad city and
      caters to patients coming from the urban areas of the city. The average daily out-patient
      visits to the hospital are 200 women. The average number of daily deliveries in the hospital
      is 25.

      All women who attended an antenatal clinic for a routine examination by gynecologist were
      evaluated on following inclusion criteria;

      1. Full term pregnant and registered for delivery at CDF Hospital Hyderabad 2.1. An absence
      of a chronic illness (Diabetes / Tuberculosis / Hypertension) 3.1. No serological marker (HBs
      Ag) of prior exposure to hepatitis B Inclusion criteria for mothers and Recruitment process
      All women who attended an antenatal clinic for a routine examination by gynecologist were
      evaluated on following inclusion criteria;

        1. Full term pregnant and registered for delivery at CDF Hospital Hyderabad

        2. An absence of a chronic illness (Diabetes / Tuberculosis / Hypertension)

        3. No serological marker (HBs Ag) of prior exposure to hepatitis B Prior to the due date
           for childbirth, while attending the antenatal clinic, these females were approached and
           informed about the study. Those who were willing to participate were given a consent
           form to sign. After the informed consent, blood was obtained by a finger prick and a
           drop of blood was put onto the Abbot's Determine ® rapid testing kit for detection of
           hepatitis B surface antigen. The Determine ® has sensitivity, (negative predictive
           value) of 98% and specificity, (positive predictive value) of 100%, compared to the
           Enzyme Link Immunosorbent Assay (96).

      The results were interpreted as follows;

        -  Two red bars meant blood is positive for hepatitis B surface antigen

        -  Single red bar meant blood is negative for hepatitis B surface antigen Women who were
           negative for hepatitis B surface antigen were then allocated into an intervention or a
           control group (details of the methodology are given below). They were followed until
           they delivered and were discharged from the hospital with a healthy baby. For vaccine
           given at birth, other researchers have also enrolled infants as subjects of the vaccine
           trials(97)(98)(99). Infants have also been selected as trial participants and the
           hepatitis B vaccine was given to infants in trials of preventing mother to child
           transmission of hepatitis B(100).

      Exclusion criteria for neonates:

      After the delivery infants born in both groups were examined by a trained midwife for
      following criteria;

        1. Weight, less than 2000 grams

        2. Signs and Symptoms of febrile Illness/sepsis

        3. Congenital Malformation

        4. Signs of Cyanosis

        5. Difficulty in breathing The newborns who fulfilled the inclusion criteria, i.e., weight
           more than 2000 grams and absence of above-mentioned criteria were followed up.

      Intervention

      One cc of intravenous blood was drawn from the peripheral veins of these healthy newborn. The
      blood was immediately centrifuged, and serum was put in a plastic container, labeled with a
      unique identification number. The serum containers were frozen and then sent using a cold
      chain container, to Pakistan Medical Research Council laboratory at Jinnah Postgraduate
      Medical Center Karachi. The serum was tested for anti-hepatitis B surface antigen antibody on
      Enzyme Immunoassay (EIA) kit DS-EIA-Anti-HBsAg, manufactured by DSI S.r.I (Italy).

      After obtaining a blood sample, infants born to mothers in the intervention group were
      administered GSK's ® recombinant hepatitis B vaccine ENGERIX 10 micrograms (µ gm),
      intramuscular in the anterolateral part of either of thighs. This birth dose of hepatitis B
      was followed by zero dose oral polio vaccine as per hospital policy. Infants born to mother
      in the control group were given oral polio vaccine as per the hospital policy.

      Subsequent vaccinations in both groups of infants were administered as per the expanded
      program on immunization schedule in Pakistan.

      After discharge from the hospital, both groups of children were followed until the completion
      of the third dose of Diptheria - Pertussis Tetanus - Hemophilus Influenza Type B - Hepatitis
      B - Pneumococcal (DPT-HiB-HBV-PCV) vaccine offered under the Expanded Program on
      Immunization. The follow up was done with caregivers at 6, 10 and 14 weeks, follow up started
      at 8 weeks and duration of follow-up was up to 10 weeks after the 3rd shot of DPT-HiB-HBV-PCV
      vaccine. After the discharge of mothers from hospital, preformed, short text messages (SMS)
      were sent to parents, reminding them of the due date for as per the vaccination schedule. One
      day after the due date of the vaccine shot, a phone call was made to confirm the child was
      vaccinated or not. The parents were approached after eight weeks of the last DPT-HiB-HBV-PCV
      vaccine shot. They were requested to bring the child to the hospital for a follow-up blood
      test to evaluate the presence of anti-HBs Ag-Ab titer in the blood. Upon the follow-up visit,
      infants were weighed, and 1 cc venous blood was drawn from the peripheral veins. Blood was
      centrifuged, and serum was stored in a plastic container labeled with a unique number. All
      the samples were then sent in cold chain to Pakistan Medical Research Council laboratory at
      the Jinnah Postgraduate Medical Center Karachi.

      Intervention Group:

      Four (4) mothers from the intervention group were shifted to a teaching hospital, prior to
      delivering a baby. Baseline blood samples were taken from 144 babies and the birth dose was
      administered. During subsequent follow-up, cell numbers of three mothers were not responsive,
      after a period of three months, they were declared as lost to follow-up. Baseline antibody
      titer in serum of fourteen infants was found to be greater than10 mIU/ml. These children were
      not followed. One child died, and parents of five children refused to continue and did not
      allow obtaining a peripheral follow up blood sample.

      Control Group:

      A high attrition of study participants happened in the control group. Thirty-two expectant
      mothers refused to participate in the study when told that their babies would not get birth
      dose hepatitis B vaccination. This attrition occurred despite an explanation of trial to the
      control group participants, prior to the enrollment. The phenomenon of high attrition in the
      control group is a well-known and well-documented effect of an unblinded trial.

      Margin of non-inferiority In a non-inferiority trial, if the upper limit of 95% confidence
      interval is less than the margin of non-inferiority i.e. delta (Δ), there is evidence of
      non-inferiority cases(48). At the protocol development stage, published literature was
      reviewed for seroprotection correlates. For the purpose of this trial, we calculated the Δ as
      the difference in seroprotection correlates with or without the birth dose of hepatitis B
      vaccine, and the Δ for this study was set to be 5%. The trial outcome set at the time of
      protocol design was not changed during the course of study.

      Sample Size In the non-inferiority trials, where the primary response variable is
      dichotomous, it is assumed that the event rate for the two interventions is equal to p i.e.

      p = p intervention = p control. With this assumption the formula becomes as under(48); 2N =
      4p (1-p) (Zα - Zβ)2 / Δ2 A brief explanation of the variables used in the equation is given
      below P = 0.957 (proportion of children attaining seroprotection correlates) (104) Δ = 0.05
      (5%) Zα = 2.57 (99% CI) Zβ = 0.89 (80% power) After solving the equation 2 N comes out to be
      228, hence 1 N =114. Thus, to get the answer to questions posed in the study; the number of
      subjects in one arm of the trial is 114. The trial was planned to end after the last follow
      up
    

Intervention name(s): recombinant hepatitis B vaccine ENGERIX 10 micrograms (µ gm),; Short text messages and calls to parents for compliance to routine immunization schedule
Intervention type(s): Biological; Behavioral
Intervention description(s): recombinant hepatitis B vaccine ENGERIX 10 micrograms (µ gm), intramuscular in the anterolateral part of either of thighs; After the discharge of mothers from hospital, preformed, short text messages (SMS) were sent to parents, reminding them of the due date for as per the vaccination schedule. One day after the due date of the vaccine shot, a phone call was made to confirm the child was vaccinated or not
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention