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PubMed2004

An analysis of rotavirus vaccine reports to the vaccine adverse event reporting system: more than intussusception alone?

BACKGROUND: The rhesus-human rotavirus reassortant-tetravalent vaccine (RRV-TV) was licensed on August, 31, 1998, and subsequently recommended for routine infant immunizations in the United States. After approximately 1 million doses had been administered, an increase in acute risk of intussusception in vaccinees led to the suspension of the use of RRV-TV and its withdrawal from the market. These postmarketing safety studies focused on a single adverse event (intussusception) and, to minimize the risk of a false-positive finding, accepted only cases that met a strict case definition. Safer rotavirus vaccines are needed to prevent the substantial global morbidity and mortality caused by rotavirus infections; their development and future use may benefit from a better understanding of the postmarketing safety profile of RRV-TV beyond intussusception. OBJECTIVE: To characterize more completely the postmarketing surveillance safety profile of RRV-TV more completely by review and analysis of Vaccine Adverse Event Reporting System (VAERS) case reports to better understand 1) whether severe adverse events other than intussusception may have occurred after RRV-TV and 2) the likely scope of gastrointestinal illnesses, of which the previously identified, highly specific intussusception cases may account for just a fraction. SETTING AND PARTICIPANTS: Infants vaccinated with RRV-TV and other vaccines in the United States and for whom a report was submitted to VAERS during September 1, 1998, to December 31, 1999. METHODOLOGY: To detect adverse events of interest other than intussusception, we used proportional morbidity analysis to compare the adverse event profile of VAERS reports among infants who received routine vaccines including RRV-TV (after excluding confirmed and suspected intussusception reports) with infants who received identical vaccine combinations but without RRV-TV. Next, to better capture all described diagnoses, signs, and symptoms associated with the suspected adverse events, a set of new codes was developed and assigned to each VAERS report. All 448 nonfatal RRV-TV-associated reports (including intussusception) were recoded manually from the clinical description on the VAERS report and categorized into clinical groups to better describe a spectrum of reported illnesses after the vaccine. Each report was assigned to one of the following hierarchical and mutually exclusive clinical groups: 1) diagnosed intussusception; 2) suspected intussusception; 3) illness consistent with either gastroenteritis or intussusception; 4) gastroenteritis; 5) other gastrointestinal diagnoses (ie, not consistent with intussusception or rotavirus-like gastroenteritis); and 6) nongastrointestinal diagnoses. RESULTS: Even after excluding intussusception cases, a higher proportion of RRV-TV reports than non-RRV-TV reports included fever and various gastrointestinal symptoms, most notably bloody stool but also vomiting, diarrhea, abdominal pain, gastroenteritis, abnormal stool, and dehydration. Distribution of RRV-TV reports by clinical groups was as follows: diagnosed intussusception (109 [24%], suspected intussusception (36 [8%]), and illness consistent with gastroenteritis or intussusception (33 [7%]), gastroenteritis (101 [22%]), other gastrointestinal diagnoses (10 [2%]), and nongastrointestinal outcomes (159 [35%]). The median time interval between vaccination and illness onset decreased incrementally among the first 4 clinical groups: from 7 days for diagnosed intussusceptions to 3 days for gastroenteritis. CONCLUSIONS: Intussusception and gastroenteritis were the most commonly reported outcomes; however, a substantial number of reports indicate signs and symptoms consistent with either illness, possibly suggestive of a spectrum of gastrointestinal illness(es) related to RRV-TV. Although VAERS data have recognized limitations such as underreporting (that may differ by vaccine) and are nearly always insufficient to prove causality between a vaccine and an adverse event, this safety profile of RRV-TV may aid better understanding of the pathophysiology of intussusception as well as development of future safer rotavirus vaccines.

Adverse Drug Reaction Reporting Systems↗

PubMed1999

[Vaccination coverage and risk factors associated to non-vaccination in a urban area of northeastern Brazil, 1994].

INTRODUCTION: The assessment of vaccination coverage and risk factors for non-vaccination is important to evaluate vaccination programs and to identify children not properly vaccinated. METHODS: A cross-sectional household survey was carried out in the municipality of S. Luís, Maranhão, Brazil by means of a standardized questionnaire. Multistage cluster sampling was used to identify children of 12-59 months of age residing in the city in 1994. The mother or other person responsible for the children was interviewed. Fifty census clusters were visited and 40 households were sampled in each. On average, 15 children were found in each cluster. Design effect was calculated for each estimate. Health service utilization was analyzed according to socioeconomic and demographic indicators, and perceived morbidity using proportional hazard modeling (Cox's regression). RESULTS: Vaccination coverage levels were 72.4% for BCG, 59.9% for three doses of polio vaccine, 57% for three doses of DTP vaccine and 54.7% for measles vaccine. Vaccination levels have remained statistically unchanged over the last three years. Lower maternal schooling continues to be associated with increased risk of non-vaccination in the multivariable analysis. CONCLUSION: Vaccination levels were low. Health education activities are one of the suggested strategies to increase vaccination coverage.

Brazil↗

PubMed2002

World Wide Web-based survey of vaccination practices, postvaccinal reactions, and vaccine site-associated sarcomas in cats.

OBJECTIVE: To quantify incidence of vaccination practices, postvaccinal reactions, and vaccine site-associated sarcomas in cats. DESIGN: Epidemiologic survey. Animals-31,671 cats vaccinated in the United States and Canada by veterinarians with World Wide Web access. PROCEDURE: Veterinarians used secure Web-based survey forms to report data regarding administered vaccines, postvaccinal inflammatory reactions, vaccine site-associated sarcomas, and detailed information and history on each sarcoma. Data were collected from Jan 1, 1998 to Dec 31, 2000, allowing a 1- to 3-year follow-up of vaccinated cats. RESULTS: Participants reported administering 61,747 doses of vaccine to 31,671 cats; postvaccinal inflammatory reactions developed in 73 cats (11.8 reactions/10,000 vaccine doses), and qualifying vaccine site-associated sarcomas developed in 2 cats (0.63 sarcomas/10,000 cats; 0.32 sarcomas/10,000 doses of all vaccines). CONCLUSIONS AND CLINICAL RELEVANCE: These findings indicate that the incidence of vaccine site-associated sarcomas is low and is not increasing. Thoughtful consideration of the relative risks and benefits of specific vaccines remains the best means of reducing the incidence of sarcomas. It is not necessary to remove postvaccinal granulomas unless malignant behavior is apparent or they persist > 4 months.

Animals↗

PubMed2000

Vaccine preventable diseases and vaccination coverage in Australia, 1993-1998.

BACKGROUND: Since the introduction of childhood vaccination for diphtheria in 1932 and the widespread use of vaccines to prevent tetanus, pertussis (whooping cough) and poliomyelitis in the 1950s, deaths in Australia from vaccine preventable diseases (VPDs) have declined by more than 99%. It is important, however, that the downward trend in morbidity and mortality from VPDs is maintained and carefully monitored, and that changes are interpreted in relation to vaccination coverage. AIM: This report aimed to bring together three national sources of routinely collected data on the morbidity and mortality (notifications, hospitalisations and deaths) from VPDs during the period 1993-1998 for the 8 diseases then on the routine childhood vaccination schedule, and for 4 other diseases potentially preventable by childhood vaccination. It also examined vaccination coverage for the same period. METHODS: Data sources included notifications from the National Notifiable Diseases Surveillance System (NNDSS), hospitalisation data from the Australian Institute of Health and Welfare (AIHW) National Hospital Morbidity Database, deaths from the Australian Bureau of Statistics (ABS) Causes of Death Collection and vaccination coverage according to the Australian Childhood Immunisation Register (ACIR). All data sources were expected to have some limitations, the most important being under-reporting for notifications and vaccination encounters, and coding errors in the hospital morbidity data. RESULTS: Notifications for the 8 diseases covered by the routine schedule declined by 42%, from an average of 11,537 cases each year in 1993-1997 to 6700 in 1998, and hospitalisations fell by 12%, from an average of 1745 per year to 1536 in 1997/1998, while deaths remained unchanged at 7 each year over the period of review (Table 1). Tetanus caused 1 or 2 of the deaths each year. However, 6 of the 7 deaths in 1997 were in infants during a major outbreak of pertussis. Pertussis caused most of the notifications, hospitalisations and deaths during the review period. While most of these were in children, 46% of the notifications and 13% of the hospitalisations occurred in persons aged 15 years or more. There were notable declines in the numbers of notifications of invasive Haemophilus influenzae type b (Hib) disease in children under 5 years of age (77%), measles (87%) and rubella (75%), and there were no notifications of diphtheria or poliomyelitis. Vaccination coverage estimated using ACIR data increased during the review period. Coverage for the first 3 doses of diphtheria, tetanus, pertussis and Hib vaccines, assessed at 1 year of age, increased from 75% to 85%, while coverage for measles-mumps-rubella (MMR) vaccine, assessed at 2 years of age, increased from 83% to 86%. It is likely that these data underestimated coverage by 5-10%, and that the increase in coverage partly reflected better reporting to the ACIR by providers.

Adolescent↗

PubMed1992

[The effect of reduced doses of BCG vaccine on the occurrence of osseous complications after vaccination].

The authors present a review on the incidence of osseous complications after calmettization with the Soviet BCG vaccine during the period from February 1, 1980 and June 30, 1985 when the total dose of the vaccine was used, as compared with the period from July 1, 1985 to December 31, 1989 when the dose of the vaccine was reduced to half. During the first period 28 cases of the disease were recorded (on average 5 cases in every year of birth) which was an incidence of 3.71/100,000 vaccinated children. After reduction of the vaccine dose to half another 11 cases of the disease were recorded, i.e. a reduction of the incidence to 2.30/100,000 vaccinated children. During the last two years of this period only one case in each vaccinated birth year was notified. A major part of the children with bone complications after calmettization was vaccinated with a batch of vaccine which contained a higher number of germs, close to the upper range of normal values. In the development of these complications thus, no doubt, among other factors also the dose of vaccine participates. As bone complications occur after calmettization even after reduction of the dose of vaccine to half, though the incidence was lower, is should be considered whether the hitherto used dose used for vaccination of neonates is not too high.

BCG Vaccine↗

PubMedDate not supplied

Embryo vaccination with infectious bursal disease virus alone or in combination with Marek's disease vaccine.

Studies with specific-pathogen-free chickens revealed that chicks hatching from eggs inoculated at the 18th day of embryonation with infectious bursal disease (IBD) vaccine viruses of low virulence (isolates TC-IBDV and BVM-IBDV) developed antibody against IBD virus (IBDV) and resisted challenge with virulent IBDV at 3 weeks of age or older. Embryo vaccination did not adversely affect hatchability of chicks or survival of hatched chicks. Chicks embryonally vaccinated with TC-IBDV had transient histologic lesions in the bursa of Fabricius at hatch. Similar but milder lesions were also noted in chickens that received TC-IBDV at hatch. The level of protection following embryo vaccination with TC-IBDV and BVM-IBDV was similar to that following vaccination with the same vaccines at hatch. Vaccine viruses of moderate virulence (isolates BV-IBDV and 2512-IBDV) were not suitable as vaccines in embryos lacking maternal antibody to IBDV, because the vaccinated chicks developed acute IBD after hatch. Isolate 2512-IBDV was not pathogenic for embryos bearing maternal antibody to IBDV. Maternal antibody against IBDV interfered with efficacy of embryo vaccination with BVM-IBDV but not with 2512-IBDV. Embryo vaccination with a mixture of vaccines against IBD and Marek's disease resulted in protection of hatched chicks against challenge with virulent IBDV and Marek's disease virus.

Animals↗

PubMed1995

Simultaneous injection of plasma-derived or recombinant hepatitis B vaccines with yellow fever and killed polio vaccines.

Previous studies have shown an absence of interaction between hepatitis B (HB) vaccine and other vaccines used in EPI programmes except for an apparent decrease of yellow fever antibody levels when hepatitis B and yellow fever vaccines are given simultaneously. We have therefore reinvestigated the interaction of these two vaccines and assessed the absence of interaction between inactivated polio vaccine and recombinant or plasma-derived HB vaccine. The immune responses to polio vaccine injected simultaneously with plasma-derived or recombinant HB vaccine were observed to be equivalent and similar to those observed in the literature. In this randomized study, the immune responses to yellow fever injected simultaneously with plasma-derived or recombinant HB vaccine were comparable to those observed after separate administration of each vaccine. Moreover, no increase in adverse reactions was noted.

Female↗

PubMed1986

Effect of simultaneous administration of live measles vaccine on the "take rate" of live mumps vaccine.

During the course of clinical studies to develop a new bivalent measles-mumps vaccine, it was established that simultaneous administration of live measles and mumps vaccines at doses contained in the monovalent vaccines resulted in a reduced seroconversion rate against mumps but not against measles. This one-way interference was resolved by increasing the dose of the mumps component in the bivalent measles-mumps and the trivalent measles-mumps-rubella vaccines above that in the monovalent mumps vaccine. On the other hand, it was not necessary to adjust the doses of the measles and rubella components in the combined vaccines. This observation requires that not only the titres of vaccine viruses must be carefully adjusted in combined live mumps vaccines but also that the heat-stability of each component in such vaccines be carefully determined to ensure that interference is not a problem during the complete shelf-life of the product. The relative doses at release of combined mumps vaccines using the Urabe Am 9 strain and the heat-stability characteristics of these products will be presented and discussed.

Antibodies, Viral↗

PubMed1989

Vaccination of harbour seals (Phoca vitulina) against phocid distemper with two different inactivated canine distemper virus (CDV) vaccines.

Two inactivated canine distemper virus (CDV) vaccines--an adjuvanted whole inactivated virus and a subunit ISCOM preparation--were tested for their ability to induce protective immunity in harbour seals (Phoca vitulina) against phocid distemper, a disease that recently killed greater than 17,000 harbour seals in the North and Baltic seas, and was shown to be caused by infection with a newly discovered morbillivirus, which is antigenically closely related to CDV. Four CDV seronegative harbour seals were vaccinated three times with the whole-virus vaccine, two with the ISCOM subunit vaccine and two were sham-vaccinated with an antigen-free preparation. Ten days after the last vaccination, when all six vaccinated animals had developed CDV neutralizing antibody titres ranging from 300 to 3000, all eight animals were challenged by the oculonasal and the peritoneal routes, with an organ suspension from dead seals. None of the six vaccinated animals developed clinical signs. The two sham-vaccinated seals died on days 14 and 18, respectively, after having shown a body temperature rise, respiratory symptoms and weight loss. In organs from both dead animals morbillivirus antigen was demonstrated with an enzyme-linked immunosorbent assay and an immunofluorescence assay. One of these two animals had developed a low titre of CDV-specific antibodies just before death. These data clearly indicate that seals can be protected from fatal challenge with the phocid distemper virus (PDV), by vaccination with certain inactivated CDV vaccines. They also reconfirm that infection with PDV should be considered the primary cause of the recent epizootic in seals.

Animals↗

PubMed1994

Response to supplementary vaccination with recombinant or plasma hepatitis B vaccine in healthy non-responding children.

Fifty-three children who failed to respond to four doses of plasma hepatitis B (HB) vaccine (anti-HBs titre < 10 IU l-1) were divided into two groups and received revaccination with either three doses of recombinant HB vaccine (10 micrograms/dose, by 0, 1, 6 month schedule; group A) or two additional doses of plasma HB vaccine (5 micrograms/dose, by 0, 1 month schedule; group B) respectively. Thirty-two vaccinees in group A had a response rate (with anti-HBs > 10 IU l-1) of 53.1% (17/32), 87.5% (28/32), and 100% (32/32) after first, second and third doses of the vaccine respectively. Twenty-one vaccinees in group B had a response rate of 61.9% (13/21) after two additional doses of plasma vaccine. High anti-HBs titres (> 1000 IU l-1) were noted in 50% of the vaccinees in group A after three doses of vaccine. Comparing anti-HBs response between group A and group B after two additional doses of HB vaccine, group A had a higher anti-HBs titre (geometric mean titre 104.7 IU l-1 versus 75.9 IU l-1) along with a better seroconversion rate (87.5 versus 61.9%). However, the differences in vaccine dose between the two groups may also be a contributory factor. Our findings indicate that three doses of recombinant HB vaccine were invariably effective in eliciting a good immune response in previous non-responders to the four doses of plasma HB vaccine. Therefore, it is speculated that these young vaccinees who did not respond to four doses of plasma HB vaccine may not be real non-responders, but hyporesponders.

Child↗

PubMed1989

Quality assessment of DNA vaccines: hepatitis-B vaccine.

Vaccines manufactured following "classical" methods contain inactivated or infectious but attenuated viruses or bacteria. In some instances, the inactivated agents are purified. In other cases, the vaccines contain protein subunits or practically pure polysaccharides. It is generally accepted that the final product cannot be completely characterised and that therefore extensive "in-process" controls are necessary to prove the consistent quality of such vaccines. Control tests are carried out on the substrate, the pooled bulk vaccine and on the final containers. Vaccines produced by recombinant DNA techniques consist of pure proteins. The production is carried out by the multiplication of the "working seed" under well-defined standardised conditions followed by clarification, extraction, purification, formulation. "In-process" controls are incorporated at each step and specifications for acceptance are formulated. The biological methods used for the classical vaccines are completed by physicochemical and immunological determinations of antigen content, identity and purity for the "new generation" products. The requirements for the manufacturers are based on the documents issued by the World Health Organisation and by the national control authorities. The marketing of vaccines is based on a lot by lot release procedure, whereby each lot is tested by the manufacturer and the national control authority before use. Hepatitis-B vaccine, derived from transformed yeast cells, is the first and sole vaccine which has obtained a world-wide license. The quality assessment of this vaccine has been achieved following the requirements for the new generation of biomolecules. It is an example for future vaccines.

Animals↗

PubMed2005

Protection against Atlantic halibut nodavirus in turbot is induced by recombinant capsid protein vaccination but not following DNA vaccination.

Fish nodaviruses (betanodaviruses) are small, non-enveloped icosahedral single-stranded positive-sense RNA viruses that can cause viral encephalopathy and retinopathy (VER) in a number of cultured marine teleost species, including Atlantic halibut (Hippoglossus hippoglossus). A recombinant protein vaccine and a DNA vaccine were produced, based on the same capsid-encoding region of the Atlantic halibut nodavirus (AHNV) genome, and tested for protection in juvenile turbot (Scophthalmus maximus). Vaccine efficacy was demonstrated in the fish vaccinated with recombinant capsid protein but not in the DNA-vaccinated fish, despite the fact that in vivo expression of the DNA vaccine-encoded antigen was confirmed by RNA in situ hybridisation and immunohistochemistry. Combined DNA and recombinant vaccine administration did not improve the effect of the latter. Surprisingly, fish vaccinated with 50 microg recombinant protein demonstrated a threefold lower survival rate than the two groups that received 10 microg recombinant protein. Neither the recombinant protein vaccine nor the DNA vaccine induced anti-viral antibodies 9 weeks after immunisation, while antibodies reactive with the recombinant protein were detectable mainly in fish vaccinated with 50 microg recombinant protein. The study also demonstrates evidence of viral replication inside the myocytes of intramuscularly challenged fish.

Animals↗

PubMed2006

Lung pathology and immediate hypersensitivity in a mouse model after vaccination with pertussis vaccines and challenge with Bordetella pertussis.

While evaluating vaccine efficacy against clinical Bordetella pertussis isolates in mice, after challenge vaccinated mice showed increased lung pathology with eosinophilia, compared to challenged, non-vaccinated animals. This led us to study bacterial clearance, lung pathology, lung TNF-alpha expression, and parameters of immediate hypersensitivity (IH), being serum IgE levels, eosinophil numbers in the bronchoalveolar lavage fluid, and ex vivo IL-4, IL-5, IL-10, IL-13, and IFN-gamma production by the bronchial lymph node cells. BALB/c mice received a combined Diphtheria (D), Tetanus (T), Poliomyelitis, and whole-cell Pertussis vaccine (WCV), a combined D, T, and three-component acellular Pertussis vaccine (ACV), aluminium hydroxide adjuvant, or PBS, 28 and 14 days before B. pertussis infection. Similarly treated non-infected mice were taken as a control. Infection induced pathology; this induction was stronger after (especially WCV) vaccination. WCV but not ACV vaccination induced TNF-alpha expression after challenge. After challenge, IH parameters were strongly increased by (especially ACV) vaccination. Vaccinated IL-4 KO mice showed similar clearance and pathology, in the absence of IgE and with reduced numbers of eosinophils. Vaccinated (Th1-deficient) T-bet KO mice showed reduced clearance and similar pathology. In summary, after challenge vaccination increased lung pathology, TNF-alpha expression (only WCV), and IH parameters. Th1 cells were critical for clearance.

Administration, Intranasal↗

PubMed2006

Hepatitis A/B vaccination of adults over 40 years old: comparison of three vaccine regimens and effect of influencing factors.

Challenged by contrasting data on low immune responses in the elderly with a combined hepatitis A/B vaccine, a randomised, controlled study was conducted to assess the immunogenicity of three hepatitis A and B vaccination regimens (group 1: combined hepatitis A/B vaccine Twinrix [GSK]; group 2: co-administered hepatitis A vaccine, Havrix [GSK]+hepatitis B vaccine Engerix -B [GSK], group 3: co-administered hepatitis A vaccine, Vaqta [Sanofi-Pasteur MSD]+hepatitis B vaccine HB VAX PRO [Sanofi-Pasteur MSD]) and the effect of influencing factors in subjects >40 years. On completion of the full vaccination course, anti-HBs seroprotection (SP) rates were 92, 80 and 71% in groups 1, 2 and 3, respectively; anti-HAV seropositivity (S+) rates were 97, 99 and 99%, respectively. In group 1, anti-HBs SP rate was non-inferior as well as superior and anti-HAV S+ rate was non-inferior to that in groups 2 and 3. Anti-HBs response was most significantly influenced by the vaccine regimen, followed by age, gender and BMI (stepwise multiple regression analysis). BMI had the most significant influence on HAV response followed by age, gender and vaccine regimen. In conclusion, Twinrix induced superior hepatitis B SP rates and similar hepatitis A S+ rates compared to concomitant administration of monovalent vaccines in subjects aged >40 years.

Adult↗

PubMedDate not supplied

Incidences of vaccine-preventable Haemophilus influenzae type b pneumonia and meningitis in Indonesian children: hamlet-randomised vaccine-probe trial.

BACKGROUND: Most studies of Haemophilus influenzae type b (Hib) disease in Asia have found low rates, and few Asian countries use Hib vaccine in routine immunisation programmes. Whether Hib disease truly is rare or whether many cases remain undetected is unclear. METHODS: To estimate incidences of vaccine-preventable Hib pneumonia and meningitis among children younger than 2 years in Lombok, Indonesia, during 1998-2002, we undertook a hamlet-randomised, controlled, double-blind vaccine-probe study (818 hamlets). Children were immunised (WHO schedule) with diphtheria, tetanus, pertussis (DTP) or DTP-PRP-T (Hib conjugate) vaccine. Vaccine-preventable disease incidences were calculated as the difference in rates of clinical outcomes between DTP and DTP-PRP-T groups. Analyses included all children who received at least one vaccine dose. FINDINGS: We enrolled 55073 children: 28147 were assigned DTP-PRP-T and 26926 DTP. The proportion of pneumonia outcomes prevented by vaccine ranged from less than 0 to 4.8%. Calculated incidences of vaccine-preventable Hib disease (per 10(5) child-years of observation) for outcome categories were: substantial alveolar consolidation or effusion, less than zero (-43 [95% CI -185 to 98]); all severe pneumonia, 264 (95% CI less than zero to 629); all clinical pneumonia, 1561 (270 to 2853); confirmed Hib meningitis, 16 (1.4 to 31); meningitis with cerebrospinal-fluid findings consistent with a bacterial aetiology, 67 (22 to 112); and admission for suspected meningitis or presenting to a clinic with convulsions, 158 (42 to 273). INTERPRETATION: Hib vaccine did not prevent the great majority of pneumonia cases, including those with alveolar consolidation. These results do not support a major role for Hib vaccine in overall pneumonia-prevention programmes. Nevertheless, the study identified high incidences of Hib meningitis and pneumonia; inclusion of Hib vaccine in routine infant immunisation programmes in Asia deserves consideration.

Bacterial Capsules↗

PubMed1985

Age-specific differences in duration of clinical protection after vaccination with meningococcal polysaccharide A vaccine.

Sequential case-control studies were used to monitor changes in the clinical protection induced by group A meningococcal polysaccharide vaccine over a 3-year period. Overall, vaccine efficacy declined from 87% 1 year after vaccination to 70% and 54% at 2 and 3 years, respectively. When stratified by age at time of vaccination the data showed that, although vaccine efficacy remained high in children greater than or equal to 4 years of age (vaccine efficacy 85%, 74%, and 67% at 1, 2, and 3 years after vaccination, respectively), it declined dramatically in those less than 4 years of age at time of vaccination (vaccine efficacy 100%, 52%, and 8%, respectively, at 1, 2, and 3 years after vaccination). Thus, a single dose of group A meningococcal vaccine does not yield lasting clinical protection in children less than 4 years of age.

Adolescent↗

PubMed1997

Vaccine failures after primary immunisation with Haemophilus influenzae type-b conjugate vaccine without booster.

BACKGROUND: Diseases of early childhood associated with Haemophilus influenzae type b (Hib) can now be prevented by vaccination. The rapid implementation of routine infant vaccination with Hib polysaccharide-tetanus protein conjugate (PRP-T) vaccine has allowed us to assess whether an accelerated 2, 3, and 4 month schedule can protect in the longer term without a booster dose and whether carrier priming influences protective efficacy. The degree of protection afforded by a catch-up programme with Hib oligosaccharide conjugate (HbOC) for older children was also assessed. METHODS: Paediatricians and microbiologists in the UK were asked to report all cases of invasive H influenzae infection in children who had received at least one dose of Hib-conjugate vaccine. Serum samples from convalescent children were obtained and the isolate was verified. Efficacy was estimated by comparing observed rates of Hib disease in those who had been vaccinated with rates predicted by age adjustment of disease rates from the prevaccine era. FINDINGS: Of 164 reports of invasive infection between Oct 1, 1992, and Oct 1, 1995, 43 were considered true vaccine failures. The estimated overall efficacy for three doses of PRP-T was 98.1% (95% CI 97.3-98.7%). Efficacy in infants aged 5-11 months was 99.1%, 12-23 months 97.3%, and 24-35 months 94.7%. In infants aged 3-11 months, who received their first dose of PRP-T after tetanus toxoid vaccination, disease was unlikely from 1 week after one dose of PRP-T vaccine (88.6% protection in the second to fourth weeks [66.8-97.7%]). The disease rate in vaccinated infants aged 2 months has declined year on year. In children aged 13 months to 2 years given HbOC, as a catch-up vaccine, the estimated efficacy was 94.0% (84.7-98.4%). INTERPRETATION: A high degree of efficacy has been observed with PRP-T vaccine given as a three-dose schedule in infancy and with HbOC as a single dose in older children. Efficacy of PRP-T appears to be enhanced by carrier priming. Although with increasing age there was a small decline in efficacy of PRP-T, Hib disease is now close to being eliminated in the UK, and we suggest that a booster is not necessary in the second year of life.

Age Factors↗

PubMed2003

Epidemiologic impact and cost-effectiveness of universal infant vaccination with a 7-valent conjugated pneumococcal vaccine in the Netherlands.

BACKGROUND: Streptococcus pneumoniae is one of the main causes of bacterial meningitis, bacteremia, pneumonia, and otitis media in the Netherlands. These diseases lead to substantial mortality, morbidity, and costs. The societal impact is especially severe because most cases occur in very young infants. OBJECTIVE: The aim of this study was to estimate the epidemiological impact and cost-effectiveness of universal infant vaccination with a 7-valent conjugated pneumococcal vaccine in the Netherlands. METHODS: Decision analysis was performed using epidemiological data and data on health care resource use from 1996 to 2001. A model was used to project the impact of pneumococcal vaccination on the incidence of pneumococcal infections in infants and children from birth to age 10 years. Costs, benefits, and health gains were estimated, and cost-effectiveness was calculated. All analyses were performed from a societal perspective. RESULTS: On average, 339 cases per year of invasive pneumococcal infection occurred in infants and children from birth to age 10 years in the Netherlands from 1996 to 2001. The model predicted that introduction of the 7-valent conjugated pneumococcal vaccine would prevent 48 cases of bacterial meningitis and 88 cases of pneumococcal bacteremia per year, as well as 42,695 cases of pneumococcal otitis media and 3411 cases of invasive pneumococcal pneumonia. The model also predicted that vaccination would save 13 lives per year and prevent 31 cases of lifelong sequelae, rendering 382 discounted quality-adjusted life-years (QALYs) gained or 329 discounted life-years gained per year. Considering these health gains, vaccination would prevent Euro 9,453,600 of direct and indirect medical costs of meningococcal and pneumococcal infections in the Netherlands, including acute medical care, management of sequelae, and lost time at work. With a vaccine price of Euro 40 per dose, the base-case cost-effectiveness ratio would be Euro 71,250 per QALY. The model was sensitive to changes in incidence of infections, vaccine effectiveness, and vaccine price. CONCLUSIONS: Our analytic model predicted that universal pneumococcal vaccination of infants in the Netherlands could prevent a large number of pneumococcal infections and considerably reduce related mortality and morbidity. However, the baseline cost-effectiveness ratio of such a vaccination program would be relatively unfavorable compared with other interventions implemented in the Netherlands.

Cost-Benefit Analysis↗