Elsevier

Vaccine

Volume 35, Issue 21, 15 May 2017, Pages 2770-2774
Vaccine

Short communication
Evaluation of storing hepatitis B vaccine outside the cold chain in the Solomon Islands: Identifying opportunities and barriers to implementation

https://doi.org/10.1016/j.vaccine.2017.04.011Get rights and content

Highlights

  • Timely birth dose coverage increased when vaccine was stored outside cold chain.

  • Temperature excursions above 37 °C were rare, but vaccine wastage was high.

  • If home births are common, an outside cold chain policy improves birth dose coverage.

  • Vaccine wastage and unreliable supply must be tackled for successful implementation.

Abstract

Monovalent Hepatitis B vaccine (HepB) is heat stable, making it suitable for storage outside cold chain (OCC) at 37 °C for 1 month. We conducted an OCC project in the Solomon Islands to determine the feasibility of and barriers to national implementation and to evaluate impact on coverage. Healthcare workers at 13 facilities maintained monovalent HepB birth dose (HepB-BD) OCC for up to 28 days over 7 months. Vaccination data were recorded for children born during the project and those born during 7 months before the project. Timely HepB-BD coverage among facility and home births increased from 30% to 68% and from 4% to 24%, respectively. Temperature excursions above 37 °C were rare, but vaccine wastage was high and shortages common. Storing HepB OCC can increase HepB-BD coverage in countries with insufficient cold chain capacity or numerous home births. High vaccine wastage and unreliable vaccine supply must be addressed for successful implementation.

Introduction

Chronic hepatitis B virus (HBV) infection can result in liver cirrhosis and cancer [1]. Infection during early childhood is strongly associated with progression to chronic infection [2]. The prevalence of chronic HBV infection in the Solomon Islands is high, estimated at 21% among all ages in 2007, and 13% among 0–9 year olds that attended the national reference hospital in 1994 [3], [4]. The World Health Organization (WHO) recommends children receive a birth dose of hepatitis B vaccine (HepB), as soon as possible after birth followed by at least two additional doses to prevent infection [5]. In the Solomon Islands, HepB and HepB birth dose (HepB-BD) were introduced into the routine immunization program in 1990 and 2001, respectively. In 2015, coverage estimates were at 98% for three doses of HepB and 65% for HepB-BD [6].

Monovalent HepB is relatively heat stable making it suitable for storage outside cold chain (OCC). Storage of HepB OCC could help to increase HepB-BD coverage with no increase in reported adverse effects where access to health care is geographically challenging, home births are common, or health facilities lack adequate cold chain capacity [7], [8], [10], [11], [12], [13], [14], [15]. Evidence shows that HepB can be stored OCC at 37 °C for 1 month or 45 °C for 1 week, and that persons administered vaccine stored at 37 °C for 1 month have similar mean geometric titers and seroconversion rates as those who receive vaccine stored at 28 °C for 1 month [7], [8], [10], [11], [12]. Storage of HepB OCC to improve timely administration of vaccine is now supported by the WHO Strategic Advisory Group of Experts on immunization [16]. Given this evidence, we conducted a pilot project in the Solomon Islands to determine the feasibility of and barriers to national implementation of a HepB-BD OCC program and to evaluate impact on coverage.

Section snippets

Material and methods

We selected 14 health facilities (HFs) from Guadalcanal, Makira, and Western provinces which lacked cold chain for vaccine storage, had >10 births per year, and were within a day of travel from the provincial capital. Each facility stored single dose, monovalent HepB (LG Lifescience) OCC for up to 28 days during a 7 month period (August 2015–February 2016). Facility health care workers (HCWs) were primarily responsible for monthly vaccine collection from the provincial pharmacy, although

Results

Of the 14 selected HFs, one was excluded as it had no assigned HCW; six had refrigerators installed after selection, but maintained HepB-BD OCC for the project. During January 2015–February 2016 there were 364 births, of which 278 (76%) were HF births. At two HFs, home births accounted for >50% of births. Among HF births, one newborn that died within 24 h was excluded; timely HepB-BD coverage increased from 30% (n = 38/125) during the pre-project period to 68% (n = 104/152) during the project period

Discussion

This study showed that storing HepB-BD OCC increased coverage among HF and home births, HCWs stored and handled monovalent HepB vaccine OCC well, and vaccine storage temperatures above 37 °C were rare. The WHO Regional Office of the Western Pacific endorses the use of HepB-BD OCC, and multiple studies conducted in the region have shown improvements in coverage [9], [10], [12], [13], [14], [15]. However, few discussed program implementation challenges. In the Solomon Islands, the biggest

Conclusions

The results of this project and the substantial body of literature suggest the Solomon Islands and countries facing similar challenges should consider introducing a HepB-BD OCC program, especially where low birth dose coverage is associated with no or unreliable access to cold chain. However, further training on vaccine forecasting would be essential before implementing a national program. Furthermore, the WHO Strategic Advisory Group of Experts on immunization now supports countries that

Conflicts of interest

None.

Funding

This work was supported by the United Nations fund for children (UNICEF).

Disclaimer

The findings and conclusions in this paper are those of the authors and do not necessarily reflect the position of the Centers for Disease Control and Prevention.

Acknowledgements

We would like to acknowledge each of the healthcare workers at the 13 health facilities included in this study for their engagement and support of this activity.

References (17)

There are more references available in the full text version of this article.

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  • Use of controlled temperature chain and compact prefilled auto-disable devices to reach 2030 hepatitis B birth dose vaccination targets in LMICs: a modelling and cost-optimisation study

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    Licensure under a CTC protocol would enable widespread ambient vaccine storage for birth dose coverage expansion and is currently being pursued by global development partners.17 Within this context, CTC has been shown to be highly cost-effective and when piloted has increased hepatitis B birth dose coverage by 27–40%,22,23,25 both of which are consistent with our model's findings. In addition, our optimisations indicate that the cost-effectiveness of achieving 90% coverage was enhanced by switching a proportion of existing community cold-chain birth dose vaccinations to CTC.

  • Seroprevalence of chronic hepatitis B virus infection and immunity to measles, rubella, tetanus and diphtheria among schoolchildren aged 6–7 years old in the Solomon Islands, 2016

    2020, Vaccine
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    Among children with vaccination cards, only 59% had received a timely HepB-BD. Improving timely HepB-BD coverage could be achieved by storing monovalent HepB outside the cold chain (OCC) as was shown in a recent pilot study in the Solomon Islands [42]. Solomon Islands is currently scaling up this successful OCC pilot to improve timely HepB-BD coverage in at least two provinces among health facilities that lack any cold chain capacity and among home deliveries.

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1

Present address: UNICEF Middle East and North Africa Regional Office, P.O. Box 1551, Amman 11821, Jordan.

2

Present address: Department of Immunization, Vaccines and Biologicals, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland.

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