Comparison of immunogenicity of hepatitis B vaccine between low and normal birth weight infants.

A comparative study was conducted to evaluate the immunogenicity of hepatitis B vaccine in low and normal birth weight infants. Hepatitis B vaccine (Hevac B Pasteur) was given to 50 low birth weight infants and 50 controls, matched by sex and date of delivery. The vaccine was given at birth, 1, 2 and 12 months of age. HBsAg and anti-HBs were assessed at birth, 4, 9 and 13 months of age by the micro-ELISA technique. Using the geometric mean titre of anti-HBs and the seroconversion rate as indicators, the immunogenicity of hepatitis B vaccine in low birth weight infants was as good as in normal birth weight infants.

Hepatitis B immunization in high risk neonates born from HBsAg positive mothers: comparison between plasma derived and recombinant DNA vaccine.

A half dose recombinant hepatitis B vaccine (HBVax II, MSD, 5 micrograms) was investigated for efficacy in the prevention of perinatal hepatitis B virus (HBV) transmission in high risk neonates born from e-antigen positive HBsAg carrier mothers as compared to the half-standard dose regimen of plasma derived hepatitis B vaccine (HBVax, MSD, 10 micrograms). Forty infants born to carrier mothers were given hepatitis B immune globulin (HBIG) 100 IU intramuscularly immediately after birth, combined with either the recombinant or plasma derived hepatitis B vaccine. The infants were randomly divided into two groups of 20 infants each. The plasma derived vaccine (10 micrograms) was given to group I, while infants in group II received the recombinant vaccine (5 micrograms) at birth, 1 and 6 months of age. There were no statistically significant differences in the efficacy and the seroconversion rate of these two combined prophylaxis regimens. The protective efficacy rate of both kinds of HBV vaccine was found to be 94.6 and 89.2 percent in group I and group II respectively. At twelve months of age, the anti-HBs seroconversion rates were 95.0 percent in group I and 84.2 percent in group II. However, the geometric mean titres in group I (179.55 mIU/ml) was significantly higher than those in group II (42.2 mIU/ml) but the anti-HBs titre was still above protective level (10 mIU/ml) in most of the infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis B immunization in high risk neonates born from HBsAg and HBeAg positive mothers: comparison of standard and low dose regimens.

A reduced dose of plasma derived hepatitis B vaccine (Hevac B) was tested for efficacy in the prevention of perinatal hepatitis B virus (HBV) transmission in high risk neonates born from e-antigen positive HBsAg carrier mothers. Forty newborn infants born of these mothers were given hepatitis B immune globulin (HBIG) 100 IU intramuscularly immediately after birth, combined with either standard or reduced doses of HBV vaccine. The infants were divided into two groups of 20 infants each. The standard dose of HBV vaccine (5 micrograms) was given to group I, while infants in group II received reduced dose (2 micrograms) at birth and at 1, 2 and 12 months of age. There was no statistically significant difference in the efficacy and antibody responses of these two combined prophylaxis regimens. The protective efficacy rate of HBV vaccine was found to be 94.0 and 93.2 percent in group I and group II, respectively. At twelve months of age, the anti-HBs seroconversion rates were 80.0 percent in group I and 86.7 percent in group II, with geometric mean titres of 84.57 mlU/ml and 78.56 mlU/ml, in group I and group II, respectively. One month after a booster at one year of age, anti-HBs could be detected in 86.7 percent of the infants in both groups. The geometric mean titres were 429.04 and 664.81 mlU/ml, in group I and group II, respectively. Anti-PreS2 antibody was detected in high titre as early as 4 months after the first dose of HBV vaccine, with a geometric mean titre of 116.30 mlU/ml and 107.97 mlU/ml, in group I and group II, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Active pre-exposure immunisation against hepatitis B virus: immunogenicity of hepatitis B vaccine in healthy Thai adults and children.

The immunogenicity of plasma derived hepatitis B vaccine (Hevac B) was studied for active pre-exposure immunisation in 176 healthy volunteer adults and 162 randomised children who had no hepatitis B virus markers. All subjects received three injections of 5 micrograms of hepatitis B vaccine intramuscularly at one month intervals. Seroconversion at 2 months after the third dose of vaccine was 96.30 percent in the children and 92.00 percent in the adults with mean anti-HBs titres of 800 mlU/ml and 353 mlU/ml respectively. The difference of anti-HBs levels between these two groups was statistically significant (p less than 0.05). Female adults had exhibited higher immune response to HB vaccine than male adults but there was no seroconversion difference between boys and girls. There were no serious local or systemic side effects of hepatitis B vaccination. It was concluded that active immunisation with plasma derived hepatitis B vaccine in non-immune children and adults is highly effective without any serious side effects or complications. The prevention of horizontal transmission of hepatitis B virus should be done by vaccination in children since they have a much better immune response to hepatitis B vaccine than adults.

Efficacy of hepatitis-B immunoglobulin and hepatitis-B vaccine in prevention of the HBsAg carrier state in newborn infants of mothers who are chronic carriers of HBsAg and HBeAg.

Combined prophylaxis of perinatal transmission of hepatitis B virus (HBV) with hepatitis-B immunoglobulin (HBIG) and hepatitis-B vaccine was investigated in 40 infants born to HBeAg positive carrier mothers. The efficacy of two combined prophylaxis schedules was compared to 78 similar infants in the control group receiving no treatment, by following the HBV markers at regular intervals up to one year of age. In both schedules, the HBIG and HBV vaccine were given at birth, followed by HBV vaccine given at 30 days and 60 days (group I) or 180 days (group II) of age. The incidence of persistent HBsAg carrier in infants born to HBeAg positive carrier mothers was significantly reduced from 92.6 percent at one year of age in the control group to zero percent (group I) and 11.5 percent (group II) in the treated groups. There was no statistical significant difference in the efficacy of these two combined prophylaxis schedules. HBIG given at birth did not interfere with infant immune response to the hepatitis B vaccine. At twelve months of age, anti-HBs could be detected in 77.8 percent of infants in group I and 89.5 percent in group II with mean titre of 621.4 and 1148.0 in group I and group II respectively. It was concluded that combined prophylaxis with HBIG and hepatitis-B vaccine immediately after birth is the best method for prevention of HBV perinatal transmission from HBeAg positive carrier mothers to their infants.

Perinatal transmission of hepatitis B virus in Thailand.

Perinatal transmission of hepatitis B virus (HBV) from asymptomatic HBsAg carrier mothers to their infants was studied in 78 mother-infant pairs by determination of HBsAg, HBeAg and anti-HBe both in the mothers and in their infants at regular intervals for those children up to the time when they reached at least one year of age. Twenty-five out of the 78 (32.1%) infants born to these mothers were HBsAg-positive 2-6 months after birth and they remained so throughout the observation period of at least one year or more. Perinatal HBV transmission occurred only in infants born to HBsAg carrier mothers who were HBeAg-positive (92.6%) but not in those born to HBsAg carrier mothers who had no detectable HBeAg. This study suggests that preventive measures against HBV transmission during the perinatal period should be taken only for infants born to HBsAg carrier mothers who are HBeAg-positive. In addition, the active immune response to HBV was studied in 75 non-HBsAg carrier infants born to HBsAg carrier mothers by determination of anti-HBs at one year of age or older. Forty-three of these infants were treated with HBIG at birth and 32 infants received no treatment. It was found that infants born to HBsAg carrier mothers who were HBeAg-positive had a better active immune response (84.2% positive for anti-HBs) than infants born to HBsAg carrier mothers who had no detectable HBeAg or anti-HBe (14.3% and 20.4% positive for anti-HBs respectively).

Vertical transmission of the hepatitis B surface antigen in Thailand.

The vertical transmission of the hepatitis B surface antigen (HBsAG) from HBsAg carrier mothers to their infants and children were studied in 42 mother-infant pairs, 27 siblings aged under 5 years and 34 fathers of these families. Thirteen out of 42 (30.9%) infants born from these mothers became HBsAg carriers at 3 to 6 months of age. Vertical transmission to their infants (76.5%) and other siblings (88.9%) occurred only in those mothers with e-antigen (HBeAg) positive but none in HBsAg carrier mothers without HBeAg. Most of the HBsAg carrier babies (70.5%) and their siblings (77.7%) born from the carrier mothers with HBeAg positive also had HBeAg in their sera. Good correlation of the presence of HBeAg and higher titer of HBsAg was found both in HBsAg carrier mothers and in their off-springs. This study clearly shows that HBsAg carrier Thai mothers with HBeAg transmitted hepatitis B virus vertically to their infants and children more readily than do the HBsAg carrier mothers without HBeAg.