Can Earlier BCG Vaccination Reduce Early Infant Mortality? Study Protocol for a Cluster Randomised Trial in Guinea- Bissau
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Open access Protocol BMJ Open: first published as 10.1136/bmjopen-2018-025724 on 24 September 2019. Downloaded from Can earlier BCG vaccination reduce early infant mortality? Study protocol for a cluster randomised trial in Guinea- Bissau Sanne M Thysen, 1,2,3 Aksel Karl Georg Jensen,4 Amabelia Rodrigues,3 Igualdino da Silva Borges,3 Peter Aaby,2,3 Christine Benn, 1,2,3 Ane Fisker1,2,3 To cite: Thysen SM, ABSTRACT Strengths and limitations of this study Jensen AKG, Rodrigues A, Introduction The BCG vaccine is designed to protect et al. Can earlier BCG against tuberculosis, but the vaccine may have broader ► This study will provide evidence regarding the vaccination reduce early infant effects. In 2014, the Strategic Advisory Group of Experts mortality? Study protocol for non-specific effects of BCG and oral polio vaccine on Immunization reviewed the literature on non-specific a cluster randomised trial in (OPV) provided at birth. effects of BCG, and concluded that the evidence was Guinea-Bissau. BMJ Open ► The trial will be the first randomised trial to as- consistent with beneficial non-specific effects and 2019;9:e025724. doi:10.1136/ sess non-specific effects of BCG and OPV in a rural requested further randomised trials. bmjopen-2018-025724 low-income setting. Methods and analyses Within the Bandim Health ► The trial tests a feasible add-on intervention to the ► Prepublication history and Project’s urban and rural health and demographic additional material for this currently WHO-recommended home visits. surveillance systems, we will conduct a cluster- paper are available online. To ► The study will provide a cost-effectiveness analysis randomised trial in six suburban districts and 55 rural view these files, please visit of providing BCG and OPV at a single home visit after villages. Infants are enrolled at a home visit before the journal online (http:// dx. doi. birth. org/ 10. 1136/ bmjopen- 2018- 72 hours of life. In intervention clusters, children are ► The trial tests co-administering BCG and OPV at vaccinated with BCG and oral polio vaccine (OPV). In 025724). birth and will not be able to conclude on separate control clusters, the caregivers are informed about non-specific effects of the individual vaccines. Received 30 July 2018 vaccination opportunities. Using Cox-proportional hazards Revised 22 August 2019 models, we will test whether BCG and OPV provided at a Accepted 30 August 2019 single home visit can reduce early infant mortality up to 60 days. home visits and are normally provided at http://bmjopen.bmj.com/ The trial was initiated with a pilot study in Biombo the health centres. The current vaccination region in June 2015. The trial was scaled up to full study policy is to provide BCG vaccine and oral including Oio and Cacheu regions in July 2016. The trial polio vaccine (OPV) at birth (vaccination was expanded to include the urban study area in July 2017. schedule, figure 1). Ethics and dissemination BCG vaccination is delayed Public health policies in low-income coun- in many low-income settings. WHO-recommended home tries are based on a one-disease-one-solution © Author(s) (or their visits are resource demanding and vaccines are not paradigm: for each of the important diseases, employer(s)) 2019. Re-use part of the recommendation. Utilising the home visits to a specific vaccine is developed. It is believed on October 2, 2021 by guest. Protected copyright. permitted under CC BY-NC. No provide BCG and OPV may provide countries with a further that the vaccine prevents only the specific commercial re-use. See rights incentive to introduce a single home visit. In countries, disease and does nothing else. Therefore, and permissions. Published by where home visits are already in place, vaccines can BMJ. most routine vaccines have not been tested easily be added to reduce early infant mortality. The trial 1 for their effect on overall mortality. OPEN, University of Southern is approved by the Guinean Ethical Committee (Reference 3–5 Denmark, Odense, Denmark However, many observational studies number: 0016/CNES/INASA/2015) and the Danish Ethics 6–9 2Research Center of Vitamins and randomised controlled trials (RCTs) Committee has given its consultative approval. The results and Vaccines, Statens Serum of the trial will be published in international peer-reviewed in low-income countries have now shown that Institut, Copenhagen S, Denmark apart from preventing specific diseases, the 3Bandim Health Project, Bandim journals. Health Project, Bissau, Guinea- Trial registration number NCT02504203; Pre-results. vaccines may also have wider effects on the Bissau immune system, which leads to changes in resis- 10 4Section of Biostatistics, tance/susceptibility to unrelated infections. University of Copenhagen, INTRODUCTION With respect to BCG, observational studies Copenhagen, Denmark WHO recommends home visits after birth to show that BCG is associated with better child 1 2 3 11 12 Correspondence to reduce neonatal mortality. Guinea-Bissau survival, which cannot be explained by 13 Dr Sanne M Thysen; has not implemented such home visits yet. prevention of tuberculosis (TB). WHO recom- s. thysen@ bandim. org Vaccinations are not an integrated part of mends BCG vaccine at birth in low-income Thysen SM, et al. BMJ Open 2019;9:e025724. doi:10.1136/bmjopen-2018-025724 1 Open access BMJ Open: first published as 10.1136/bmjopen-2018-025724 on 24 September 2019. Downloaded from Rural site The rural HDSS was established in 1990. The BHP teams survey women of fertile age and their children below the age of 5 years in randomly selected clusters of villages in all the nine health regions in the country. Children in the three rural regions closest to Bissau (Oio, Biombo and Cacheu) are eligible for the study. The rural clusters are followed with two monthly visits by the mobile teams. At all visits, the women are Figure 1 Recommended vaccination schedule in Guinea- asked whether they are pregnant. When a pregnancy Bissau. is registered, the woman’s nutritional status is assessed by measurement of a mid-upper-arm-circumference countries. Typically low-weight (LW) children (<2500 g) are (MUAC); information on antenatal care is collected prior only vaccinated when they reach 2500 g. These children are to giving birth, as well as at the first visit after delivery. assumed to be immunologically immature, and BCG vacci- Socioeconomic factors (type of roofing, type of bathroom, nation is therefore often delayed. However, in three RCTs possession of a mobile phone, radio and generator) are in Guinea-Bissau, BCG-at-birth reduced neonatal mortality registered. After the delivery, information on the place in LW children, the combined analysis showed a mortality of delivery (home, health facility) and who assisted the reduction of 38% (95% CI: 17% to 54%).6 7 TB is very rare delivery is collected. in early childhood14 and the effects can therefore not be Urban site ascribed to prevention of TB. The effect of BCG-at-birth on neonatal mortality was seen already during the first 3 The urban HDSS was established in 1978. Field assistants days post-vaccination, the reduction in mortality being 45% follow children below the age of 3 years through home (7%–68%).9 This rapid effect suggests that the effect is due visits every third month. Pregnancies are registered every to changes in the innate immune system. month and followed monthly until birth. When a preg- Recent immunological studies support that BCG induces nancy is registered information on ethnic group, gesta- epigenetic changes in monocytes, which reprogram the tional age, use of mosquito net is collected. After the innate immune system to increased pro-inflammatory delivery, information on place of delivery (home, health responses against unrelated pathogens.15 16 These find- facility) is collected. All children in the urban study area ings thus provide biological mechanisms whereby BCG will be eligible for the study. could exert non-specific beneficial effects, protecting the 16 17 Study nurses recipients against non-targeted infectious diseases. Prior to study start, we selected study nurses to conduct Approximately 75% of neonatal deaths occur within the home visits. In the rural study area, study nurses were 13 http://bmjopen.bmj.com/ first week of life, but BCG is rarely given at birth in low-in- selected in collaboration with the regional health author- come countries; only 11% of the children receive BCG in 18 ities. The nurses were selected among nurses working at a the first week of life in Guinea-Bissau. A major reason health centre with a catchment area corresponding to the for this delay is the focus on reducing wastage of vaccines. study clusters, so the home visits can be done in addition Freeze-dried vaccines like BCG have to be used within 6 to their normal routines. For the urban study area, the hours after reconstitution with a diluent. Therefore, a vial BHP employed a study nurse fulltime. of BCG vaccine is often not opened unless 10–12 children are present for vaccination. Hence, there are many missed Community key informants vaccination opportunities. If BCG vaccine has profound In the rural areas, to ensure that the nurses are informed on October 2, 2021 by guest. Protected copyright. effects on neonatal mortality and morbidity many lives immediately about deliveries, we use community key could be saved by providing BCG earlier. informants (CKIs). CKIs were selected among residents in In this study, we aim to study the effect of BCG and OPV each rural village to collect information about pregnan- vaccinations provided at a single home visit within 72 cies, deliveries and deaths. The CKI communicate imme- hours after birth on early infant mortality and morbidity diately any delivery in the village to the study nurse.