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Biomedical subjects

A Safary

Publications and source records attributed to A Safary.

At least 37 records · Page 2Linked to original sources
PubMed1997

Safety and immunogenicity of inactivated hepatitis A vaccine in patients with chronic liver disease.

The safety and immunogenicity of inactivated hepatitis A vaccine was evaluated in patients with chronic liver disease. Sixty hepatitis A virus antibody (anti-HAV) seronegative patients with chronic liver disease (56 chronic hepatitis B and four chronic hepatitis C) and from 17 to 47 years of age received a dose of 1440 ELISA units of the inactivated hepatitis A vaccine at month 0, and a booster at month 6. Anti-HAV seroconversion (> or = 33 mIU/mL) was 57.6% (34/59) on day 15, and reached 93.2% (55/59) 1 month after primary vaccination. At month 6, the seropositivity of anti-HAV decreased before the booster to 69.0% (40/58). All vaccinees had measurable titers of anti-HAV 1 month after booster vaccination, and were still seropositive at month 12. After initial vaccination, the geometric mean titers of anti-HAV among vaccine responders were 158, 264, 74, 1309, and 409 mIU/ml at day 15 and months 1, 6, 7, and 12. Overall, 59.7% (71/119) of the vaccine doses administered were followed by mostly minor reactions. The majority of symptoms reported were local, all of which resolved within 3 days after vaccination. No significant changes in serum liver enzyme levels were detected after vaccination. Thus, an inactivated hepatitis A vaccine was safe in patients with chronic liver disease while the immune response was inferior to that observed in healthy subjects reported in a previous study.

Adolescent↗
PubMed1997

Hepatitis B vaccine containing surface antigen and selected preS1 and preS2 sequences. 1. Safety and immunogenicity in young, healthy adults.

The safety and immunogenicity of a yeast-derived recombinant hepatitis B virus (HBV) vaccine containing surface antigen (S) and selected preS1 and preS2 sequences (S-L*) were compared with those of a vaccine prepared with S alone (Engerix-B). S-L* consisted of composite particles containing S and L* at a ratio of 70/30. L* encompassed amino acid residues 12-52 of preS1 residues 133-145 of preS2, and the entire S domain. A total of 100 healthy, HBV-seronegative, young adults were randomized to receive 20 micrograms/dose of either S-L* or Engerix-B under double-blind conditions according to a 0-, 1-, 2-, 12-month schedule. In vivo humoral and in vitro lymphoproliferative responses to S and preS regions were monitored. Addition of the selected preS sequences to S did not enhance the in vivo humoral anti-HBs response but improved the in vitro stimulating capacity of the antigen (L*) in S-L* primed subjects.

Adult↗
PubMed1997

Hepatitis B vaccine containing surface antigen and selected preS1 and preS2 sequences. 2. Immunogenicity in poor responders to hepatitis B vaccines.

The immunogenicity of a yeast-derived recombinant hepatitis B virus (HBV) vaccine containing surface antigen (S) and selected preS1 and preS2 sequences (S-L*) was compared with that of a vaccine containing S alone (Engerix-B) in 32 healthy adults with a previous history of poor response (anti-HBs < 10 mIU ml-1) after at least three consecutive monthly doses of hepatitis B vaccines. The poor responders were randomized to receive three additional 20-microgram doses of either S-L* or Engerix-B in a double-blind fashion according to a 0-, 1-, 2-month schedule. In vivo humoral and in vitro lymphoproliferative responses to the S and preS regions were monitored. Although the addition of the selected preS sequences to S did not enhance the in vivo humoral anti-HBs response, the administration of the three additional vaccine doses, irrespective of their preS content, induced seroprotective anti-HBs levels in most vaccinees (29/32, 91%). In vitro proliferative responses to HBV surface antigens were only observed in subjects displaying anti-HBs titers > 1000 mIU ml-1 after the third additional vaccine dose.

Adult↗
PubMed1997

Long-term antibody persistence after booster vaccination with combined tetravalent diphtheria tetanus, whole-cell Bordetella pertussis and hepatitis B vaccine in healthy infants.

Combining HB vaccine with routine paediatric vaccines has been recognized as the best means of universal vaccination against hepatitis B. Our objective was to evaluate the long-term antibody persistence of such a combined vaccine in an area of high hepatitis B endemicity. We have shown that a DTPw-HB vaccine was safe and immunogenic when given as a booster dose at 18 months of age. One month after the booster dose of DTPw-HB vaccine, at least 97.8% of subjects had seroprotective anti-HBsAg levels, and 1 year later at least 93.9% of these subjects remained seroprotected against HBsAg. Immune responses to the DTPw components were similar or greater than those of the commercial DTPw vaccine given to the control group. This DTPw-HB vaccine, which showed good long-term anti-HBsAg antibody persistence, could advantageously replace separate DTPw and HB vaccines in areas of high hepatitis B endemicity in terms of clinical, economic and strategic benefits.

Antibodies, Bacterial↗
PubMed1997

Long-term hepatitis B vaccine in infants born to hepatitis B e antigen positive mothers.

Neonates of hepatitis B surface antigen (HBsAg) positive and hepatitis B encoded antigen (HBeAg) positive mothers received 10 micrograms of recombinant hepatitis B vaccine at months 0, 1, 6, or 0, 1, 2, 12, with or without immunoglobulin at birth, and were followed up to the age of 8 years for HBsAg, anti-HBc, and anti-HBs. Some were boosted at month 60. The overall vaccine protection at month 12 was 96.2%. No child became a chronic carrier beyond the age of 3 years, showing that this vaccine provides immediate protection against HBsAg carriage, and long term protection against fetally acquired HBsAg. After month 60 hepatitis B serological markers without disease, indicating re-exposure to HBV, reappeared in comparable numbers among boosted and non-boosted children (5 for a total of 167 children). This vaccine provides long-term protection against hepatitis B chronic carriage and infection in high risk neonates with or without a month 60 booster. A booster at the age of 5-6 years or 11-12 years would reduce HBV infection, viral circulation and transmission, while ensuring long-term antibody persistence.

Carrier State↗
PubMed1996

Response to Hepatitis A Vaccine in Children after a Single Dose with a Booster Administration 6 Months Later.

Background: Children are of an age group susceptible to infection by the hepatitis A virus (HAV). Active immunization of children against HAV became reality in 1993, when the first pediatric hepatitis A vaccine was licensed. This initial vaccine required two injections to induce a full immune response in recipients. The purpose of this study was to assess the feasibility of a single dose primary vaccine plus a booster after 6 months against hepatitis A in children. Methods: A total of 60 healthy and seronegative children between 2 and 13 years of age were administered inactivated hepatitis A vaccine, containing 720 enzyme-linked immunosorbent assay (ELISA) units (EL.U) of hepatitis A antigen, intramuscularly in the deltoid region at months 0 and 6. Symptoms were recorded by parents or guardians on individual diary cards. Antibodies against HAV (antiHAV) were measured using an ELISA inhibition assay, and a seropositive titer was defined as being >=20 mIU/mL. Results: Fifteen days after the single primary dose, 96% of the vaccinees were seropositive with a geometric mean titer (GMT) of 351 mIU/mL. The seropositivity rate reached 100% 1 month after the first dose, with a GMT of 305 mIU/mL. Prior to the second dose at month 6, 93% remained seropositive, and the GMT was 153 mIU/mL. By month 7, 1 month after the second vaccination, the seropositivity rate recovered to 100% with a rise in GMTs to 3644 mIU/mL. Local symptoms were reported after 23.9% of doses, and general symptoms after 19.7% of doses. All symptoms were of short duration and resolved spontaneously. Conclusions: This inactivated vaccine against hepatitis A is safe, well-tolerated, and excellently immunogenic when administered to children following a single dose plus booster course at months 0 and 6.

Journal Article↗
PubMed1996

Single-dose hepatitis A vaccination: comparison of different dose levels in adolescents.

The effect of two dose levels of inactivated hepatitis A vaccine was investigated for immunogenicity and reactogenicity in an open study in adolescents. The subjects were randomized into two groups and to receive a priming dose of 720 EL. U or 1440 EL. U of hepatitis A antigen, respectively. A booster of the same dose level was given at month 6. In group 1, receiving 720 EL. U, the seroconversion rates at 15 days and 1 month were 92% and 99%. The corresponding rates for group 2, receiving 1440 EL. U, were 98% and 100%. Higher geometric mean titres of antibody to hepatitis A virus were noted at 1, 6 and 7 months in the group receiving 1440 EL. U. The vaccine was well tolerated in both groups. The most frequent side effect was transient soreness at the site of inoculation. No serious adverse reactions were observed. The study demonstrated that inactivated hepatitis A vaccine is safe and immunogenic at a dose level of 720 EL. U or 1440 EL. U in adolescents.

Adolescent↗
PubMed1996

Two year old hepatitis A vaccine is as good as new.

This was a randomized, controlled, double-blind study assessing the reactogenicity and immunogenicity of newly produced vs 2 year old hepatitis A vaccine. Overall 215 non-immune volunteers, 18-39 years old were divided into four groups and administered vaccine at months 0, 1 and 6. Three groups each received a different vaccine lot which had been stored at 4 degrees C for 2 years, and one group received recently produced vaccine as control. The mean local and general adverse reaction rates were 59.1% and 17.4%, respectively, and all vaccinees had seroconverted by month 2. There were no significant differences in geometric mean anti-hepatitis A virus (HAV) antibody titres between the four groups. In conclusion 2 year old HAV vaccine is safe and equally immunogenic as newly produced vaccine.

Adolescent↗
PubMed1996

Safety and immunogenicity of a combined hepatitis A and hepatitis B vaccine in young healthy adults.

BACKGROUND: A combination of hepatitis A and hepatitis B monovalent vaccines could offer advantages for disease control programs in terms of convenience, compliance and cost. METHODS: Under randomized, double-blind conditions, 156 healthy young adults were divided into 3 groups to receive 1 of 3 lots of a combined hepatitis A/hepatitis B vaccine administered at months 0, 1, and 6. Safety and immunogenicity were assessed after each dose. RESULTS: Transient and predominantly mild reactions were reported by slightly more than half the vaccinees; no serious adverse effects were relate to vaccination. One month after dose 2, all subjects had converted to the hepatitis A component. Geometric mean titers (GMTs) of antibodies of hepatitis A virus varied from 4415 to 4882 mIU/ml in the three groups. For hepatitis B, most vaccinees (73%-92%) had protective levels of antibodies to hepatitis B virus (anti-HBs) after the second dose, and all were sero-protected after the booster. Anti-HBs GMTs at month 7 ranged from 1917 to 3298 mIU/ml. CONCLUSIONS: No statistically significant differences were observed between vaccine lots. The combined hepatitis A/hepatitis B vaccine was safe and clinically well tolerated and induced immune responses quantitatively similar to those obtained with the respective monovalent vaccines.

Adolescent↗
PubMed1996

Single dose-inactivated hepatitis A vaccination schedule for susceptible youngsters.

OBJECTIVE: To investigate the feasibility of a single-dose primary hepatitis A vaccination for young travelers. METHODS: One hundred and nineteen susceptible youngsters, 9-18 yr old, received a dose of 720 ELISA units of the inactivated hepatitis A vaccine at month 0, and then a booster at month 6. RESULTS: Antibodies to hepatitis A virus (anti-HAV) seroconversion ( > or = 20 mIU/ml) in these vaccinees was 91% (106/117) on day 15, and reached 99% (118/119) 1 month after the single-dose vaccination. At month 6 before the booster, 97% (110/113) of the vaccinees still had detectable anti-HAV. All vaccinees (113/113) had measurable titers of anti-HAV 1 month after booster vaccination, and were still seropositive (68/68) at month 12. The anti-HAV response was found to be slower in vaccinees positive for hepatitis B surface antigen (11/16, 68.8%), compared with noncarrier vaccinees (95/101, 94.1%; p < 0.01) 15 days after the priming dose. After initial vaccination, the geometric mean titers of anti-HAV among vaccine responders were 220, 255, 117, 3308, and 1094 mIU/ml at day 15 and months 1, 6, 7, and 12, respectively. CONCLUSION: These results suggest that a single dose of hepatitis A vaccine could be a good alternative to immune serum globulin administration for immunoprophylaxis in young healthy travelers.

Adolescent↗
PubMed1995

Evaluation of a combined tetravalent diphtheria, tetanus, whole-cell pertussis and hepatitis B candidate vaccine administered to healthy infants according to a three-dose vaccination schedule.

A vaccine combining hepatitis B with diphtheria, tetanus and whole-cell Bordetella pertussis (DTPwHBV) would facilitate the attainment of universal vaccination of infants against hepatitis B. A candidate vaccine was administered to 42 infants beginning at 7-15 weeks of age. Antibodies were measured from pre- and postvaccination blood samples. After three doses, at least 94.9% of the infants were protected against hepatitis B, diphtheria and tetanus. Responses to B. pertussis were considered adequate. No serious adverse events were reported. These results indicate that this candidate vaccine is safe and immunogenic when administered to infants according to a three-dose schedule, with doses 2 months apart.

Diphtheria-Tetanus-Pertussis Vaccine↗
PubMed1995

Clinical experience with an inactivated hepatitis A vaccine.

Clinical trials of an inactivated hepatitis A vaccine have encompassed 104 studies completed by December 1993 in 27 countries. Studies involved 50,677 subjects and administration of > 120,000 vaccine doses. Results show that the vaccine is safe, clinically well-tolerated, and highly immunogenic in all age groups. A seroconversion rate of 100% is achieved 1 month after primary vaccination. Vaccine-induced antibody titers persist after a primary vaccination course for > or = 1 year with a single dose of 1440 ELISA units (EL.U.) in adults and after two doses of 360 EL.U. in children. A booster dose 6-12 months after the first vaccine dose induces very high antibody titers, which according to a mathematical model, are expected to protect against hepatitis A for > 20 years. The vaccine is equally immunogenic when administered simultaneously with other traveler vaccines, therefore enabling flexible and convenient vaccination against hepatitis A.

Adult↗
PubMed1994

Protection against hepatitis A by an inactivated vaccine.

OBJECTIVE: To evaluate the safety and efficacy of a new inactivated hepatitis A vaccine. DESIGN: Double-blind randomized controlled trial stratified by community. SETTING: Community-based in Thailand. STUDY PARTICIPANTS: A total of 40,119 children, aged 1 to 16 years, attending 148 primary schools: 38,157 (95%) entered surveillance a mean of 138 days after receiving vaccine dose 1; 33,586 (84%) completed the controlled trial of 532 days; and 31,075 (81%) received crossover vaccine and remained under surveillance until day 844. INTERVENTION: Participants received hepatitis A vaccine or control hepatitis B vaccine starting January 7, 1991 (doses in months 0, 1, and 12), and crossed over to the alternate vaccine 18 months later. MAIN OUTCOME MEASURE: Cases of hepatitis A (symptoms, alanine aminotransferase levels of 45 U/L or higher, and IgM to hepatitis A virus) were identified by evaluating school absences of 2 or more days. RESULTS: There were no serious adverse reactions despite administration of more than 109,000 doses of hepatitis A vaccine. Among initially seronegative recipients of two doses of hepatitis A vaccine, the proportion with 20 mIU/mL or more of antibody to hepatitis A virus before and 5 months after a 1-year booster was 94% and 99%, respectively. Of 6976 episodes of illness during the controlled trial, there were 40 cases of hepatitis A; 38 were in the control group. Of the 40 cases, six, all in controls, occurred after the 1-year booster dose. Following two doses of hepatitis A vaccine (days 138 through 386), protective efficacy was 94% (95% confidence interval, 79% to 99%); cumulative efficacy including the postbooster period (days 138 to 532) was 95% (95% confidence interval, 82% to 99%). The two hepatitis A vaccine recipients who had symptomatic infections (257 and 267 days after dose 1) appeared to have been partially protected since their illnesses were brief and associated with only slight increases in alanine aminotransferase. CONCLUSIONS: Inactivated hepatitis A vaccine is safe; when administered in two doses, it protects against hepatitis A for at least 1 year.

Adolescent↗
PubMed1994

Single dose inactivated hepatitis A vaccine: rationale and clinical assessment of the safety and immunogenicity.

In comparison with the classical immunisation schedules (0-1-6 or 0-1-12 months) for hepatitis A, a 0- and 12- or a 0- and 6-month schedule would have important advantages by reducing the number of injections and discomfort and increasing scheduling convenience and patient compliance. It would be convenient if a single dose with enough antigen could protect both rapidly and for at least 12 months, when the booster dose would be given. Several clinical trials have been carried out with an inactivated hepatitis A vaccine containing 1,440 EL.U. (1 ml), according to a 0-12 and a 0-6 vaccination schedule. This hepatitis A vaccine is safe and well tolerated. It offers a rapid seroresponse: 14 days after a single dose the seroconversion is 88% (95% C.I.: 84.6-90.9). The 0-12 schedule study showed good persistence of hepatitis A virus (HAV) antibodies with a seroconversion rate of almost 95% at month 12. Booster doses given at 6 or 12 months result in a substantial rise in antibody levels; according to these antibody titres, the 1,440 EL.U. vaccine can be expected to confer comparable duration of protection as the 720 EL.U. vaccine, i.e., 10-20 years. Preliminary data show that timing of the booster may not be critical for the antibody response. In conclusion, the 1,440 EL.U. hepatitis A vaccine is safe, offers rapid seroconversion, and is highly immunogenic. The persistence of HAV antibodies until month 12 allows a certain flexibility in the administration of the booster: month 6 or 12, and a 0-12 or 0-6 schedule can increase the vaccination compliance.

Adolescent↗
PubMed1994

Immunogenicity and safety in adults of hepatitis A virus vaccine administered as a single dose with a booster 6 months later.

An inactivated vaccine against hepatitis A was administered as a single 1,440 enzyme-linked immunosorbent assay (ELISA) units dose at month 0 with a booster at month 6 to 200 subjects divided into two age groups: group 1, 20-39 years (n = 134) and group II, 40-62 years (n = 66). At day 15, the seropositivity rates were 90% and 77% in groups I and II, respectively. At month 1 the seropositivity rate was 97% in both groups. At month 6 the seropositivity rates were 94% and 88% in groups I and II, respectively. One month after the booster, at month 7, 100% in both groups had become seropositive. The vaccine was well tolerated and did not cause any severe reactions. The results indicate that a single high vaccine dose offers protection against hepatitis A virus (HAV) for at least 6 months in the majority of cases where rapid vaccination is required even in travellers of older age. A booster dose will ensure long-term protection.

Adult↗
PubMed1994

Inactivated hepatitis A vaccine: reactogenicity, immunogenicity, and long-term antibody persistence.

This trial evaluated the reactogenicity, kinetics of antibody induction, and long-term immunogenicity of a 720 enzyme-linked immunosorbent assay units (EL.U.) antigen dose of an inactivated hepatitis A vaccine (Havrix, SmithKline Beecham Biologicals, Rixensart, Belgium). One hundred six healthy adult volunteers were enrolled to receive vaccine intramuscularly according to a 0, 1, and 6-month schedule. The vaccine was well tolerated. The most frequently reported local symptom was soreness, observed following 37.1% of all doses. Headache was the most frequently reported general symptom observed following 12.9% of documented vaccine doses. The administration of one vaccine dose induced seropositivity (anti-hepatitis A virus [HAV] > or = 20 mIU/ml) in 91% of all vaccinees 1 month later. The second vaccine dose resulted in seropositivity of the remaining vaccinees at month 2. All subjects remained seropositive for HAV antibodies at month 6, at which time the booster vaccine dose was given. At month 7, all vaccinees had anti-HAV titres > 200 mIU/ml. Serological results obtained at months 12, 18, 24, and 36 showed that antibodies against HAV induced by the vaccine booster dose persist for at least 30 months following its administration. All 49 subjects followed up until month 36 had antibody titres > or = 20 mIU/ml. The geometric mean titre (GMT) decreased by 60% from month 7 to month 12; between month 12 and 36, the GMT decreased by approximately 14% per period of 12 months. According to the vaccine-induced antibody kinetics and the magnitude of antibody level decrease over time, the predicted duration of antibody persistence is estimated to be at least 20 years.

Adolescent↗
PubMed1994

Interruption of an outbreak of hepatitis A in two villages by vaccination.

During a large community-wide outbreak of hepatitis A in two adjoining villages in Slovakia with a total of 5,000 inhabitants we administered to schoolchildren the first commercially available vaccine against hepatitis A (HAVRIX, Smith-Kline Beecham Biologicals, Rixensart, Belgium) in an attempt to control the progress of the epidemic. Soon after the start of the vaccination programme, an abrupt decrease in the occurrence of cases in the school was observed. In the village school with 624 schoolchildren, 404 had received a first dose of 360 enzyme-linked immunosorbent assay (ELISA) units (EL.U) and 373 a second dose 1 month later. Subsequent to the start of vaccination there were eight clinical cases of hepatitis A among the 157 children without a history of hepatitis A who remained unvaccinated and only 1 case in the vaccinated school children, giving attack rates of 5.1% and 0.25% in the two groups, respectively. Among the remaining 63 children, one was found seropositive when screened and 62 had a history of hepatitis A at the start of the vaccination programme. These 63 children were not offered vaccine. No cases occurred in that group. During the epidemic, three cases occurred an average of 20 days following its administration among 19 children who received immune globulin (IG). Cases in the whole population of the villages also ceased soon after the vaccination of the children had started. The vaccine was found more effective than postexposure IG in interrupting the epidemic in the whole community.

Adolescent↗