Biomedical subjects

H L Bock

Publications and source records attributed to H L Bock.

At least 19 recordsLinked to original sources

PubMed2002

Reactogenicity and immunogenicity of a varicella vaccine in healthy seronegative and seropositive subjects.

The epidemiology of varicella appears to be changing: an unexplained upward age shift in varicella prevalence and a subsequent dramatic rise in morbidity and mortality among adolescents and adults have highlighted the importance of effective varicella mass vaccination programs. This age shift is being seen in temperate regions but is particularly marked in tropical and sub-tropical regions. To assess the need for serological pre-screening in mass vaccination programs, we performed an open study to compare the reactogenicity and immunogenicity of a varicella vaccine in initially seronegative and seropositive subjects to see whether there was an increase in reactogenicity among initially seropositive subjects. Two hundred and forty-six seronegative and seropositive male and female subjects, aged 9 months to 60 years, received a single dose of a live attenuated varicella virus (Oka-strain) vaccine, Varilrix (GlaxoSmithKline Biologicals, Rixensart, Belgium). Subjects were categorized according to antibody status and age group; serum antibodies were measured before and after vaccination (day 42). The study showed that there was no difference in reactogenicity in initially seropositive vaccinees compared with initially seronegative subjects. The varicella vaccine was found to be safe and well tolerated in all age groups. Ninety-eight percent of initially seropositive and 94.8% of initially seronegative subjects reported no clinical signs or symptoms during the 42-day follow-up period. The vaccine was immunogenic in both groups. The seroconversion rate after 6 weeks in initially seronegative subjects was 94.3%. In 53.0% of initially seropositive subjects of all age classes, a 4-fold rise in antibody titer was observed.

Adolescent↗

PubMed2002

Concomitant administration of varicella vaccine with combined measles, mumps, and rubella vaccine in healthy children aged 12 to 24 months of age.

The reactogenicity and immunogenicity of three combined measles, mumps and rubella (MMR) vaccines and one administered with a varicella vaccine was studied in infants. The vaccines were Priorix (designated MeMuRu, Group 1), M-M-R II (Group 2), Triviraten (Group 3) and Priorix + a varicella vaccine, Varilrix (Group 4). Fever was greater in Group 2 (61.3%) compared to Group 1 (48.5%; p = 0.033) or Group 3 (37.1%; p = 0.009). Rash with fever was reported in Group 2 (4.8%) and Group 4 (3.3%), but not for Group 1. Anti-measles, -mumps and -rubella seroconversion was similar for Group 1 (96.1%, 96.1% and 100%, respectively), Group 4 (98% for all three), and Group 2 (91.5%, 93.6% and 97.9%) 60 days post-vaccination. GMTs for measles (3,053.7-3,412.2 mIU/ml), mumps (1,001.5-1,158.8 U/ml) and rubella (68.7-89.1 IU/ml) were similar for Groups 1, 2 and 4 at Day 60. Antibody persistence was noted 2 years post-vaccination. The MeMuRu + varicella combination showed no clinically relevant increase in reactogenicity and should facilitate introduction of a varicella vaccine into national immunization schedules.

Antibodies, Viral↗

PubMed2001

Higher anti-hepatitis B response with combined DTPw-HBV vaccine compared with separate administration in healthy infants at 3, 4 and 5 months of age in Slovakia.

To help achieve universal infant immunisation against hepatitis B, the World Health Organisation has recommended the development of a combined diphtheria, tetanus and pertussis (DTP) and hepatitis B vaccine (HBV). The advantages come from the fact that DTP coverage is estimated to be over 80% worldwide and a combined DTP-HB vaccine would increase the coverage of HBV. This study was conducted to compare the immunogenicity and reactogenicity of a combined DTP-HB vaccine with separate, concomitant administration of DTP and HBV vaccines. One hundred and twenty infants were randomised in a 1:1 ratio to one of the two vaccination regimens, given as three injections at approximately 3, 4 and 5 months of age. The only difference in immunogenicity between the two regimens was a higher antibody response to hepatitis B in the group given the combined vaccine, possibly as a result of the adjuvant effect of the whole cell pertussis component of the DTP vaccine. Both vaccine regimens were well tolerated.

Diphtheria Antitoxin↗

PubMed2001

Immunogenicity and adverse effects of live attenuated varicella vaccine (Oka-strain) in children with chronic liver disease.

Varicella infection may cause significant morbidity and mortality especially in immunocompromised persons. Children with chronic liver disease who undergo liver transplantation and need long term immunosuppressive therapy are at risk to acquire the infection. Twenty-nine children (aged 1-12 years) with chronic liver disease were enrolled to receive one dose of live attenuated varicella vaccine (Oka-strain). During the 16-week follow-up period, no vaccine-related serious adverse events were reported. Seroconversion rates at 8 weeks post vaccination were 100%. Geometric mean titer (GMT) values and seropositive rates at 16 weeks tended to relate to the clinical severity of liver disease. This study demonstrates that varicella vaccine is safe and Immunogenic in children with chronic liver disease.

Chickenpox Vaccine↗

PubMed2000

Age related seroprevalence of antibodies to varicella in India.

OBJECTIVE: To determine the age related prevalence of Varicella Zoster Virus (VZV) antibodies in India. SETTING: This was a cross sectional multicentric study performed in 4 major cities of India: Calcutta (outpatients), Mumbai (outpatients), Lucknow (walk-in patients to a diagnostic laboratory, orphanage and factory workers) and Bangalore (outpatients and walk-in patients to a diagnostic laboratory). METHODS: A total of 1609 volunteers from birth to 40 years of age were included into the study. IgG antibodies against VZV were determined using commercial kits (ELISA-Enzygnost). RESULTS: Overall seroprevalence of anti VZV antibodies was 68. 22percnt. The age related seroprevalence rate of anti VZV antibodies was 29percnt in the age group of 1-5 years, 51.1percnt in 5-10 years, 71.7percnt in 11-15 years, 79.8percnt in 16-20 years, 88.1percnt in 21-30 years and 91.1percnt in 31-40 years. CONCLUSION: A significant proportion of adolescents and adults are susceptible to varicella in India, as in other tropical countries

Adolescent↗

PubMed2000

Seroprevalence of hepatitis A virus and varicella zoster antibodies in a Javanese community (Yogyakarta, Indonesia).

Hepatitis A virus (HAV) cause an acute inflammation of the liver. Varicella-zoster virus (VZV) cause chickenpox (varicella) and herpes zoster. Effective vaccines against hepatitis A and varicella are available for children, adolescents and adults. In order to implement an appropriate vaccination policy, a baseline to assess the potential benefits and sections of the population who would benefit most are required. We investigated seroprevalence of hepatitis A virus and varicella zoster antibodies in a Javanese community. A total of 1,103 subjects were studied. The 600 subjects aged 4 to 9 years were sampled between 23 October and 2 November, 1995. The other subjects were sampled between 12 October and 1 November, 1996. The overall prevalence of anti-HAV in cohort was 28.7%. Anti-HAV seroprevalence rates were below 30% until the age of 15 and below 40% until the age of 25. The anti-varicella seroprevalence showed only in two thirds of seropositive population at the age of 15. The results of the study have implications for vaccination strategies for both hepatitis A and varicella zoster.

Adolescent↗

PubMed1999

A randomized comparative trial in order to assess the reactogenicity and immunogenicity of a new measles mumps rubella (MMR) vaccine when given as a first dose at 12-24 months of age.

An open, randomized multi-center trial, involving 700 infants, was conducted in order to compare a new measles mumps rubella (MMR) vaccine, SB MMR (containing a Jeryl Lynn derived mumps strain RIT 4385) with a widely used vaccine, Merck MMR, when given to children between 12-24 months. Infants were divided between 2 groups; group 1 received SB MMR while group 2 received Merck MMR. Solicited local and general symptoms were recorded using diary cards and antibody levels were measured using ELISA assays. There was a significantly lower incidence of redness (p < 0.001) and swelling (p = 0.03) observed in group 1 compared with group 2. The incidence of all other solicited local and general symptoms were comparable between groups. In initially seronegative subjects equivalent seroconversion rates and post-vaccination GMTs were observed between groups. In conclusion, these results demonstrate that SB MMR is safe and well tolerated when given to children at this age range, and has an equivalent immunogenic profile compared to the widely used Merck MMR vaccine.

Analysis of Variance↗

PubMed1998

Immunogenicity and reactogenicity of a Haemophilus influenzae type b tetanus conjugate vaccine when administered separately or mixed with concomitant diphtheria-tetanus-toxoid and acellular pertussis vaccine for primary and for booster immunizations.

UNLABELLED: With an increasing number of new vaccines available for routine childhood immunization, combination vaccines are needed in order to maintain or achieve a high compliance with recommended immunization programmes. In a prospective, randomized, comparative, multi-centre study, 822 healthy infants were enrolled to receive three doses of either a candidate or a commercially available Haemophilus influenzae type b (Hib) vaccine concomitantly with diphtheria-, tetanus- acellular pertussis (DTaP) vaccine. Study subjects were randomly allocated to one of the following groups: (1) separate, or (2) mixed injection of DTaP and candidate Hib vaccine, or (3) separate injection of DTaP and commercial Hib vaccine. One year later the first 189 study subjects received either separate or mixed injections of the same Hib and DTaP vaccines as booster doses. Evaluation of reactogenicity was based on diary cards completed by parents. Immunogenicity was documented by measuring IgG antibody concentrations in serum samples taken before and 4 weeks after primary and booster vaccination. No serious adverse events occurred and most local and systemic reactions were mild to moderate. Booster doses were more reactogenic than primary doses with all groups. Antibody concentrations against pertussis antigens were similar to those seen with DTaP alone. All but one subject had protective antibody concentrations against diphtheria and tetanus. Primary immune response to the Hib vaccine was significantly lower in the group receiving the mixed Hib-DTaP vaccine, however, > or = 95% of vaccinees had anti-Hib antibody concentrations > or = 0.15 microg/ml and there was a marked booster response (> 100-fold) in all groups. CONCLUSIONS: Mixing DTaP and Hib vaccines for primary immunization caused a decrease in anti-Hib antibody response, although after primary immunization as after booster doses, all subjects showed antibody concentrations considered to be protective for invasive Hib disease. Mixing of the vaccines did not result in increased reactogenicity.

Analysis of Variance↗

PubMed1998

Factors influencing the spread of pertussis in households.

UNLABELLED: The objective of this study was to compare the spread of pertussis in children and adults being secondary contacts after household exposure. The study was nested in an efficacy trial of an acellular pertussis vaccine. The spread of the disease was also monitored with respect to gender and antibiotic therapy. A total of 453 index cases, of which 133 were monitored for adult disease, fulfilled the WHO definition of pertussis. They had contacts to 173 unvaccinated children aged 6-47 months, and a total of 101 adults with pertussis were followed. Detection of the bacteria, or a significant increase of specific antibodies confirmed the diagnosis. Secondary spread of the disease was assumed, when a household member coughed for 7 days or more and had laboratory evidence for pertussis. Crude attack rates (AR) were 69% in children and 31% in adults (P < 0.05). AR in children were independent of gender but more women than men (P=0.02) were affected in those households where the index case was a child. Erythromycin treatment of the index case reduced the AR in exposed toddlers from 80% to 57% (P=0.06), and in exposed adults from 40% to 21% (P=0.2). Erythromycin therapy in contacts did not alter the clinical course of the disease significantly. CONCLUSIONS: In a household study of pertussis, 69% of children and 31% of adults (more women than men) contracted the disease. Erythromycin reduced the number of infections in household contacts, but did not alter the clinical course in those who contracted pertussis.

Adult↗

PubMed1998

The new DTPw-HBV-Hib combination vaccine can be used at the who schedule with a monovalent dose of hepatitis B vaccine at birth.

An open, randomized, clinical trial was conducted in order to assess the reactogenicity and immunogenicity of DTPw-HBV and Haemophilus influenzae type b (Hib) vaccines when given either as a mixed administration or as separate concomitant injections using the WHO schedule at 6, 10 and 14 weeks of age, following a dose of HBV at birth. There were no clinically relevant differences in the immune response to any component between the mixed and separate administrations. In fact the anti-tetanus GMTs were significantly higher (p=0.002) in mixed administration (3.9 IU/ml) compared with the separate administration (1.9 IU/ml). However although all subjects achieved anti-PRP titers > or = 0.15 microg/ml, higher anti-PRP GMTs were seen in the group receiving the separate administration. Importantly, the addition of Hib did not adversely alter the reactogenicity profile of DTPw-HBV. This report which demonstrates that this novel combination can be used in WHO recommended schedule.

Analysis of Variance↗

PubMed1997

Reactogenicity and immunogenicity of a booster dose of a combined diphtheria, tetanus, and tricomponent acellular pertussis vaccine at fourteen to twenty-eight months of age.

OBJECTIVES: The primary objective was to assess the nature and incidence of adverse events after a fourth dose of a tricomponent acellular pertussis-diphtheriatetanus vaccine given in the second year of life after primary vaccination with the same vaccine at 3, 4, and 5 months of age. A secondary objective was to analyze the immunogeniecity of the booster vaccination. DESIGN: Of the 5361 children enrolled (aged 14 to 28 months), adverse reactions were specifically solicited from the first 1863 enrollees for the first 4 days after vaccination and then were unsolicited for the remainder of the 4 weeks of follow-up (group 1). In the next 3498 subjects, safety and reactogenicify were entirely unsolicited for this 4-week period (group 2). Immunogenicity was analyzed by means of prebooster and postbooster serum antibody titers for all vaccine components in a random subgroup of 197 children from group 1. RESULTS: Soliciting symptoms elicited reports of at least one symptom in 1314 of 1809 children in group 1 (72.6%), including 993 (54.9%) with local and 885 (48.9%) with general symptoms during the first 4 days after vaccination. When symptoms were gathered in an unsolicited fashion, only 580 of 3498 children in group 2 (16.6%) had a reported symptom during this time, consisting of 344 (9.8%) local and 319 (9.1%) general symptoms, respectively. An unsolicited symptom, areactive edematous swelling of the whole thigh, occurred in 62 children (1.1%), with 45 and 17 reports in groups 1 and 2, respectively. The vast majority of all reported symptoms were mild to moderate, and all children recovered without sequelae. Fourteen serious adverse events were reported, but none was considered to be related to the vaccination. Immunogenicity analysis showed a vaccine response to pertussis toxin in 99.5% of subjects, to filamentous hemagglutinin in 98.5%, and to pertactin (69 kd outer membrane protein) in 99%. All subjects had postvaccination antibody titers of 0.1 IU/ml or greater against diphtheria and tetanus toxoids.

Antibody Formation↗

PubMed1997

Booster immunization of low- and non-responders after a standard three dose hepatitis B vaccine schedule--results of a post-marketing surveillance.

Seventy-nine low-responders and 83 non-responders after a previous three-dose hepatitis B (HB) vaccine course at 0.1, and 6 months were enrolled to receive additional 20 micrograms recombinant HB vaccine doses every 2 months until all had anti-HBs levels > or = 100 mIU ml-1. After the first booster, 65.4% had anti-HBs levels > or = 100 mIU ml-1, 17.9% were low-responders (10-99 mIU ml-1), and 16.7% remained non-responders (< 10 mIU ml-1). All complying non-responders developed anti-HBs levels > or = 100 mIU ml-1 after the third booster at the latest, whereas all low-responders reached this level after the second booster. Although body mass index affected the response to the first hepatitis B booster, when full compliance to regular revaccination was ensured, all non- and low-responders eventually reached sufficient anti-HBs levels.

Adolescent↗

PubMed1997

Long-term persistence of anti-HAV antibodies following active immunization with hepatitis A vaccine.

Seventy-one anti-hepatitis A virus (HAV) negative volunteers were immunized against hepatitis A. An inactivated hepatitis A vaccine (HAVRIX, SmithKline Beecham), derived from tissue cell cultures, at single doses of 720 ELISA units was used following a schedule of vaccinations at month 0.1 and 6. The vaccines were tested for the presence of HAV antibodies 1 month after each vaccination and then after 2, 3, 4 and 5 years. The annual decrease of anti-HAV titres was 25%. Five years after vaccination a protective antibody titre, varying between 20 and 5200 mIU ml-1, could be demonstrated in all 47 retested volunteers with a geometric mean titre (GMT) of 442 mIU ml-1. Levels of anti-HAV-antibodies following active immunization were significantly higher in female volunteers. This could be consistently demonstrated throughout the observation period. Based on these data the antibody persistence was calculated over time. GMTs at protective levels higher than 20 mIU ml-1 can be expected to persist for at least 15 years.

Adult↗

PubMed1997

Factors influencing the analysis of secondary prevention of pertussis.

The aim of this study was to evaluate factors that influenced the spread of pertussis in secondary contacts after household exposure. The data were acquired during a prospective household-contact study into the efficacy of an acellular vaccine. The spread of the disease was monitored with respect to various case definitions of pertussis, socio-economic factors, household composition, and antibiotic therapy. A total of 453 index cases had contact with 173 unvaccinated children aged from 6 to 47 months. Depending on the clinical case definition, the attack rates (AR) in children with a laboratory-confirmed Bordetella infection increased from 55% for the WHO definition to 69%, when a less stringent definition was used. AR in children were independent of age and gender. The social status of the family had no significant influence on the AR in children. Erythromycin treatment of the index case reduced the AR from 64% to 51% (p = 0.08). These factors should be taken into consideration when studies into the secondary prevention of pertussis by acellular vaccines are initiated.

Child, Preschool↗

PubMed1997

Safety and efficacy of acellular pertussis vaccines: the Mainz study and other recent studies.

Following concerns about the safety and reactogenicity profile of diphtheria, tetanus and whole cell pertussis vaccines (DTwP), new and less reactogenic alternatives were developed over the last two decades. The new diphtheria, tetanus and acellular pertussis vaccines (DTaP) no longer consist of the whole bacterial cell but of either extracts or of a few highly purified components. While it soon became clear that DTaP vaccines are significantly less reactogenic than DTwP vaccines, their efficacy was disputed and remained unproven. First studies and epidemiological data from Japan suggested vaccine efficacy rates (VE) of about 80%; however, the first blinded clinical trial from Sweden documented a much lower VE. Worldwide, seven large DTaP efficacy trials have recently been completed. Our own efforts included a large safety trial with 22505 vaccinees and, nested in this setting, a prospective household contact study. Typical WHO-defined pertussis developed in 7 of 112 DTaP vaccinated children following household exposure as compared to 96 cases in 173 children not vaccinated against pertussis. Thus, vaccine efficacy was calculated to be 88.7% (95% CI 76.6 to 94.6). The median duration of spasmodic cough in the few children vaccinated with DTaP who did start coughing was 17 days as compared to 35 days in unvaccinated children. No waning of protection was observed. None of the confounding variables analyzed influenced study results in favour of DTaP. Following administration of more than 67000 DTaP doses, 153 serious adverse events were reported. Eight events were considered possibly related and five were considered related to the study vaccine. According to additional study results from the other trials it can be concluded that DTaP vaccines, like DTwP vaccines, are safe and effective. The choice between DTwP and DTaP should be based on acceptance of the reactogenicity profile, coverage rates achieved, costs and other factors in each individual country.

Clinical Trials as Topic↗

PubMed1996

Immunogenicity of a recombinant hepatitis B vaccine in adults.

OBJECTIVES: To evaluate the immunogenicity and reactogenicity of a recombinant hepatitis B vaccine in health care staff under routine use and unselected conditions and to investigate factors that influence the response to vaccination. METHODS: This prospective postmarketing surveillance study was performed in unselected health care staff and their relatives (age range, 12-60 years) at 58 hospitals. Overall, 880 subjects were administered a 20-microgram dose of a vaccine at 0, 1, and 6 months according to the prescribing information and under routine hospital practice, and they were tested for antibody to hepatitis B surface antigen after the third dose at the hospitals routine laboratory. The principal outcome measures were antibody to hepatitis B surface antigen titers that were expressed as the seroprotection rate (SPR) (SPR [given as a percentage], > or = 10 mlU/ mL), spontaneously reported adverse events, and geometric mean titers (in milli-international units per milliliter). RESULTS: The compliance to the 3-dose schedule under routine hospital practice was 98.1%. The immune response was good in all age groups, and the overall SPR was 97.8% at 1 month after the third dose in field conditions with unselected health care workers. The SPR in vaccinees (age range, 40-59 years) was close to 95%. Age (P < .001), smoking (> or = 10 cigarettes per day) (P < .001), Broca index (> 110%) (P < .001), antibody to hepatitis B surface antigen testing (> 8 weeks after the last dose) (P = .03), chronic underlying disease (P = .04), and male gender (P = .04) were factors associated with lower geometric mean titers in routine vaccine use. No serious adverse events were reported. CONCLUSION: The large immune response that was elicited by this hepatitis B vaccine in adults under daily routine field conditions reflected reality, with a high SPR also found in elderly and other persons with risk factors associated with a lower immune response.

Adolescent↗

PubMed1996

Efficacy of acellular pertussis vaccine in early childhood after household exposure.

OBJECTIVE: To evaluate the efficacy of a three-dose primary vaccination with a diphtheria-tetanus tricomponent acellular pertussis vaccine against "typical" pertussis, defined as a spasmodic cough of 21 days or longer with confirmation of Bordetella pertussis infection by culture or serology. DESIGN: Passive monitoring for suspected first household (index) cases of typical pertussis in six areas in Germany comprising 22,505 children vaccinated with study vaccine at 3, 4, and 5 months of age. Blinded, prospective follow-up of household contacts of index cases for incidence and progression of pertussis. SETTING: Six areas in Germany with a high incidence of pertussis. SUBJECTS: Four hundred fifty-three households with index cases comprising 360 evaluable contacts eligible for analysis of vaccine efficacy. MAIN OUTCOME MEASURE: Vaccine efficacy from attack rates of pertussis in household contacts classified by vaccination status. RESULTS: Of the 173 nonvaccinated household contacts, 96 developed typical pertussis, compared with seven of 112 contacts vaccinated with acellular pertussis vaccine. Vaccine efficacy was consequently calculated to be 88.7% (95% confidence interval, 76.6% to 94.6%). Protection did not wane until at least the time recommended for booster vaccination. None of the analyzed potential confounding factors--age, socioeconomic status, erythromycin treatment, household composition, center effect, and selection bias--influenced study results in favor of the vaccine. CONCLUSIONS: Under conditions of intense household exposure, primary vaccination with acellular vaccine protected against pertussis until at least the time recommended for booster vaccination. The vaccine can be expected to be equally or more effective in settings with lower infectious pressure.

Bordetella pertussis↗

PubMed1996

Immunogenicity of an inactivated hepatitis A vaccine administered according to two different schedules and the interference of other "travellers" vaccines with the immune response.

A total of 2036 persons consulting vaccination centers in Germany were vaccinated with an inactivated hepatitis A vaccine (containing 720 ELISA units of antigen) either according to the standard schedule (two vaccinations given 4 weeks apart) or to an abbreviated schedule (two vaccinations given 2 weeks apart) in a controlled clinical study. The abbreviated schedule induced a similar rate of seroconversion and geometric mean antibody titre as compared to the standard schedule. The incidence of reactions reported after vaccination was similar in both groups. When other "travellers" vaccines were given simultaneously neither the immunogenicity nor the reactogenicity of the hepatitis A vaccine were influenced. These findings have considerable practical importance in the prevention of hepatitis A in travellers.

Adolescent↗