A 3.90 V iron-based fluorosulphate material for lithium-ion batteries crystallizing in the triplite structure.

Li-ion batteries have empowered consumer electronics and are now seen as the best choice to propel forward the development of eco-friendly (hybrid) electric vehicles. To enhance the energy density, an intensive search has been made for new polyanionic compounds that have a higher potential for the Fe²âº/Fe³âº redox couple. Herein we push this potential to 3.90 V in a new polyanionic material that crystallizes in the triplite structure by substituting as little as 5 atomic per cent of Mn for Fe in Li(Fe(1-δ)Mn(δ))SO4F. Not only is this the highest voltage reported so far for the Fe²âº/Fe³âº redox couple, exceeding that of LiFePO4 by 450 mV, but this new triplite phase is capable of reversibly releasing and reinserting 0.7-0.8 Li ions with a volume change of 0.6% (compared with 7 and 10% for LiFePO4 and LiFeSO4F respectively), to give a capacity of ~125 mA h g⁻¹.

Efficacy of hepatitis B vaccine in the Gambian expanded programme on immunisation.

Because of the high prevalence of hepatitis B virus (HBV) infection in The Gambia, HBV vaccination has been incorporated into the national expanded programme on immunisation. We have assessed the efficacy of the vaccine against HBV infection and chronic carriage by examining 720 3-4-year-old children who had received the vaccine in infancy and 816 who had not received it. The vaccine was 84% (95% CI 78-89%) effective against infection and 94% (84-98%) effective against chronic carriage. Vaccinated infants of mothers positive for hepatitis B surface and e antigens were at greater risk of breakthrough infection and chronic carriage than infants of uninfected mothers. The high vaccine efficacy against the HBV carrier state, the main risk factor for the development of chronic liver disease and liver cancer, offers hope that the prevalence of these diseases may be reduced in the future.

PIP: As part of the Gambia Hepatitis Intervention Study, hepatitis B antigens and antibodies were assayed in 720 3-4 year old children who had received 4 doses of 10 mcg plasma-derived hepatitis B vaccine in infancy, the findings were compared with 816 controls. The cross sectional study took place from September, 1990, to July, 1991. Study subjects were tested for hepatitis B core antigen (HBcAg), as well as antigens and antibodies to hepatitis surface, e, and core protein, and those testing positive were tested a year later for HBsAg to determine chronic carrier status. Children negative for core antibody and surface antigen were considered uninfected; those positive for core antibody were considered infected; those positive for surface antigen 2 times 6 months apart were considered carriers. 4.6% of the vaccinated children were infected, and 0.6% were chronic carriers. 3 of these carriers had infected or carrier mothers, and 1 had only received 1 dose of vaccine. In the controls, there were 29% judged infected by anti-HBc, including 13% who were also positive for HBsAg. 86% of these were considered chronic carriers when tested a year later. Thus the vaccine was estimated to be 84% effective against infection and 94% effective against chronic carriage. The current Gambian vaccine consists of 2.5 mcg recombinant hepatitis B vaccine.

The Gambia Hepatitis Intervention Study: follow-up of a cohort of children vaccinated against hepatitis B.

Hepatitis B vaccine has been introduced into The Gambia's national Expanded Programme on Immunization, with the aim of evaluating the impact on chronic liver diseases and in particular on hepatocellular carcinoma. As part of the project, a cohort of 1000 children was recruited to assess the long-term protection induced by the vaccine. The first 3 years of follow-up are described. By the age of 3 years, 95% of the children had protective antibody levels; 4 (0.6%) are known to be carriers in contrast to the 90-140 that would be expected in the absence of vaccination. The protective effectiveness of vaccine in preventing chronic carriage in the first 3 years of life is thus estimated as 95%. Since the risk of becoming a carrier is highest in those infected early in life, these results are encouraging.

Response to hepatitis B vaccine in relation to the hepatitis B status of family members.

The influence of the hepatitis B status of family members on the response to hepatitis B vaccine of an infant has been examined in 395 families. The presence of one or more HBsAg-positive family members did not appear to have any effect on the vaccine response. This is an encouraging finding as children born into carrier families are at an increased risk of becoming carriers themselves. That the vaccine response of such children is as good as for those born into non-carrier families means that they are likely to be protected against the carrier state by the vaccine.

PIP: As part of The Gambia Hepatitis Intervention Study (designed to protect children from hepatitis and therefore liver cancer when adults), researchers took blood samples from at least 291 families of 293 index children from Brikama in the western region and 2 neighboring health centers in the Upper River Division (URD) in the eastern area of The Gambia who had received the hepatitis B virus (HBV) vaccine to examine vaccine response in infants in relation to the pattern of HBV infection in their families. 1 family member tested positive for hepatitis B surface antigen (HBsAg) in at least 30% of the children. The researchers did not find a correlation between the level of antibody in the index children and the HBsAg status of the family. 23% of families in Brikama had at least 1 HBsAg positive member compared to 37% in URD (p=.01). Even though no association existed between child's response to the vaccine and type of dwelling, an association did exist between HBsAg positive family members and type of dwelling. 35% of families who lived in a house constructed of mud or grass had at least 1 HbsAG positive family member whereas only 19.7% who lived in a concrete house had at least 1 HBsAg positive family member (p.02). Further, 40.8% of families who lived under a thatched roof had at least 1 HbsAg positive family member compared to 24.8% who had a corrugated roof (p.02). The researchers suggested that houses constructed of mud or grass or with a thatched roof may harbor more insects which transmit HBV. The socioeconomic factors of sanitation and water supply did not contribute to HBV infection. They concluded that the HBV status of a child's family did not affect his/her response to the vaccine. Therefore the vaccine protects children at high risk of becoming HBV carriers.