Improving birth dose coverage of hepatitis B vaccine.

Administration of a birth dose of hepatitis B vaccine (HepB vaccine) to neonates is recommended to prevent mother-to-infant transmission and chronic infection with the hepatitis B virus (HBV). Although manufacturers recommend HepB vaccine distribution and storage at 2-8 degrees C, recognition of the heat stability of hepatitis B surface antigen stimulated research into its use after storage at, or exposure to, ambient or high temperatures. Storage of HepB vaccine at ambient temperatures would enable birth dosing for neonates delivered at home in remote areas or at health posts lacking refrigeration. This article reviews the current evidence on the thermostability of HepB vaccine when stored outside the cold chain (OCC). The reports reviewed show that the vaccines studied were safe and effective whether stored cold or OCC. Field and laboratory data also verifies the retained potency of the vaccine after exposure to heat. The attachment of a highly stable variety of a vaccine vial monitor (measuring cumulative exposure to heat) on many HepB vaccines strongly supports policies allowing their storage OCC, when this will benefit birth dose coverage. We recommend that this strategy be introduced to improve birth dose coverage, especially in rural and remote areas. Concurrent monitoring and evaluation should be undertaken to affirm the safe implementation of this strategy, and assess its cost, feasibility and effect on reducing HBV infection rates. Meanwhile, release of manufacturer data verifying the potency of currently available HepB vaccines after exposure to heat will increase confidence in the use of vaccine vial monitors as a managerial tool during storage of HepB vaccine OCC.