Antibody responses to recombinant, yeast-derived hepatitis B vaccine in teenage New Zealand children.

Three groups of healthy teenage New Zealand children were given 2.5 micrograms, 5 micrograms and 10 micrograms, which is the currently recommended dose, of Merck Sharp and Dohme recombinant yeast-derived hepatitis B vaccine at time 0, 1 and 6 months and tested for antibody responses to vaccine and for other hepatitis B virus markers. Seroconversion rates exceeded 98% in all three groups. Geometric mean titres (GMT) of the anti-HBs increased with higher doses. There was no significant differences in GMT between the sexes. Under the conditions of this study, 2.5 micrograms doses of this vaccine induced an excellent antibody response in children 12-14 years of age.

A seroepidemiological study of the prevalence of hepatitis B infections in a hyperendemic New Zealand community.

The prevalence of hepatitis B surface antigen (HBsAg) and its antibody (anti-HBs) were studied in 93% of the population of the New Zealand township of Kawerau. Sera were collected from 7901 subjects over six months old, and 3318 (42%) had markers of hepatitis B virus (HBV) infections. Five hundred and nineteen (6.6%) were positive for HBsAg and 485 (96.4%) of 503 retested were confirmed as chronic carriers. HBsAg prevalence was 5.4% in the 0-4 years age group but only 1 of 66 children under one year old was positive suggesting that later cross infection, rather than perinatal transmission was the major factor responsible for the high pre-school carrier rate. Total HBV marker prevalence increased dramatically in early school years and peak marker prevalence was 67.7% in the 15-19 year age group. Prevalence of HBsAg was more than four times higher in non-europeans than in Europeans (Caucasians). Other factors significantly associated with hepatitis B virus marker prevalence in children were: number of years spent in Kawerau, which was associated with anti-HBs prevalence; and size of household, which was associated with HBsAg prevalence. Number of siblings was not a significant risk factor over and above the effect of size of household. Factors associated with marker prevalence in adults were: number of years spent in Kawerau, which was associated with anti-HBs; birth in the Northern half of the North Island, which was associated with both HBsAg and anti-HBs; size of household, which was more strongly associated with HBsAg prevalence; and amateur tattoos, which were associated with anti-HBs prevalence but not with HBsAg prevalence.

Low dose hepatitis B vaccination in children.

One hundred and sixty-nine children negative for hepatitis B surface antigen (HBsAg) and antibody (anti-HBs), were given three doses of hepatitis B vaccine at monthly intervals. Doses were two micrograms or four micrograms given intradermally (ID) or intramuscularly (IM). All children were tested for HBsAg, anti-HBs and antibody to hepatitis B core antigen (anti-HBc) one month after the second dose of vaccine. Overall, 74% of children on two micrograms doses and 71% of children on four micrograms doses responded to two doses of vaccine by the production of anti-HBs. At this point, mass immunisation of other susceptible children was commenced. Four of 92 (4%) three to five year old subjects and 20 of 77 (26%) nine to 12 year olds were found to be anti-HBc positive alone, indicating prior infection. All 77 older children were further tested two months after the third dose of vaccine. All 20 who were anti-HBc positive, sero-converted for anti-HBs. Of the remaining 57, 52 (91%) produced anti-HBs at acceptable geometric mean titres (GMT). Three doses of two micrograms of H-B-VAX, given at monthly intervals were chosen for mass vaccination of high risk susceptible children in this mobile community, providing over 90% sero-conversion at low cost with a minimum of side effects.

Prevalence of hepatitis B infections in a multiracial New Zealand community.

Plans to control hepatitis B virus (HBV) infections in a high risk mixed race community, included the need for prevalence studies of HBV markers. Accordingly 7901 subjects, 93% of the population of Kawerau, where European and non-European children are present in almost equal numbers, were tested for hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs). Positive HBsAg sera were titred and tested for hepatitis B e antigen (HBeAg). Highest rates for HBsAg and anti-HBs combined, were found in the 15-19 year old age groups; 61.6% in Europeans and 74.5% in non-Europeans. HBsAg prevalence was 4.2% and 18.2% respectively in the same groups. Ninety-six point four percent of 503 HBsAg positives followed up were confirmed as carriers. Infectivity as shown by HBeAg prevalence and HBsAg titre was highest in 0-10 year olds and declined with age. Prevalences were low in children aged less than one year old, suggesting that perinatal transmission was not a major factor in childhood carriage. Therefore attempts to control acquisition of carriage by vaccinating only those children of HBeAg positive mothers are unlikely to be successful.

Torulopsis glabrata endocarditis complicating aortic homograft valve treated with 5-fluorocytosine: case report with discussion of antifungal chemotherapy.

A case of Torulopsis glabrata endocarditis occurring in a patient 14 months after aortic homograft valve replacement is reported. The infection was not controlled by amphotericin B which led to progressive renal impairment. Re-operation was delayed by the development of multiple infarctions due to coronary emboli. The infection was subsequently eradicated by oral treatment with the newer antifungal agent, 5-fluorocytosine, but death of the patient eventually occurred from an arrhythmia related to the persisting myocardial failure consequent upon episodes of transmural infarction. Current evidence favours the use of early re-operation in all cases of endocarditis in addition to aggressive chemotherapy with a combined regime of amphotericin B and 5-fluorocytosine. Clinical pharmacology of 5-fluorocytosine is briefly discussed.