Safety and Immunogenicity of a Combination: Measles, Mumps, Rubella and Varicella Vaccine (ProQuad®)

BACKGROUND

A combination measles, mumps, rubella, and varicella vaccine (ProQuad, Merck & Co., Inc, West Point, PA) was evaluated in five clinical trials. Use of ProQuad would result in fewer injections for children and would facilitate universal immunization against all four diseases.

OBJECTIVE

To describe the combined results obtained from the studies conducted during the clinical development program for ProQuad.

METHODS

A total of 5833 healthy children, 12-23 months of age, and 399 healthy children, 4-6 years of age, received 1 or 2 doses of ProQuad in five controlled clinical trials. M-M-R II and VARIVAX were used as the control for most studies. Safety was evaluated for six weeks postvaccination and immunogenicity was assessed six weeks after each dose by a sensitive assay (ELISA or gpELISA).

RESULTS

A single dose of ProQuad in 12- to 23-month-old children was shown to be as immunogenic as a single dose of M-M-R II and VARIVAX and was generally well tolerated. ProQuad can be used concomitantly with other vaccines (hepatitis B and Hoemophilus influenzoe b). A higher rate of fever was reported after 1 dose of ProQuad compared to M-M-R II and VARIVAX, but fever episodes were transient without long-term sequelae. Both a 2-dose regimen of ProQuad in 12- to 23-month-olds and use of ProQuad in place of M-M-R II at 4-6 years were shown to be immunogenic and well tolerated. The incidence of adverse experiences following a second dose of ProQuad was lower than that following the initial dose.

CONCLUSIONS

A single dose of ProQuad is as immunogenic as M-M-R II and VARIVAX and is well tolerated in a 1- or 2-dose schedule. ProQuad should easily fit into the routine immunization schedule.

Risk of rheumatoid arthritis following vaccination with tetanus, influenza and hepatitis B vaccines among persons 15-59 years of age

BACKGROUND

Associations between vaccinations, particularly hepatitis B, and onset of rheumatoid arthritis (RA) have been reported, but examined in few large-scale studies.

METHOD

Onset of RA cases and dates of vaccination against hepatitis B, tetanus, and influenza were identified in a retrospective chart review of approximately 1 million Kaiser Permanente Northern California members ages 15-59 years from 1997 through 1999. In a cohort analysis, rates of new-onset RA were compared between vaccinated and unvaccinated within 90, 180, and 365 days. In a case-control analysis, rates of vaccination during exposure intervals (90, 180, 365, and 730 days) were compared between cases and controls using conditional logistic regression.

RESULTS

378 RA cases were included in the cohort analysis; 37 additional cases were included in the case-control analysis. In the cohort analysis the relative risks of RA onset within 90, 180, or 365 days of hepatitis B vaccination were not significant (R.R.=1.44, p=0.53; R.R.=1.67, p=0.22; R.R.=1.23, p=0.59 respectively). We found a possible association between RA and influenza vaccine in the previous 180 and 365 days in the cohort analysis (R.R=1.36, p=0.03; R.R.=1.34, p=0.01 respectively), but in the case-control analysis, cases were no more likely than controls to have received any of the three vaccines.

CONCLUSIONS

In this large retrospective study we found no statistically significant association between exposure to hepatitis B vaccine and onset of RA. A possible association between RA and influenza vaccination in the cohort study was not borne out in the larger case-control analysis.

The blind nasotracheal aspiration method is not a useful tool for pathogen detection of pneumonia in children

Background

Acute lower respiratory infection (ALRI) is a major cause of hospitalization for children in China, while the etiological diagnosis of ALRI remains a challenge. This study was performed to evaluate the utility of the blind Nasotracheal aspiration (NTA) in the pathogen detection in ALRI through an evaluation of the test's specificity.

Methodology/Principal Findings

A hospital-based study of children ≤3 years was carried out from March 2006 through March 2007 in Suzhou University Affiliated Children's Hospital, including 379 cases with ALRI from the respiratory wards, and 394 controls receiving elective surgery. Nasopharyngeal swabs (NPS) and NTA specimens were taken on admission. S. pneumoniae was isolated from 10.3% of NTA samples from ALRI children, H. influenzae from 15.3%, and M. catarrhalis from 4.7%. The false positive rate—the strains from NTA in control group children—was 8.4% (95% CI: 5.8%–11.4%) for S. pneumoniae, 27.2% (95% CI: 22.7–31.5%) for H. influenzae, and 22.1% (95% CI: 18.0%–26.2%) for M. catarrhalis. The agreement between NPS and NTA in the control group was over 70%.

Conclusion/Significance

The blind NTA test is not a useful test for etiologic diagnosis of ALRI.

Lack of association between age at varicella vaccination and risk of breakthrough varicella, within the Northern California Kaiser Permanente Medical Care Program

BACKGROUND

Varicella vaccine currently is recommended for children between 12 and 18 months of age. However, rates of breakthrough varicella have been reported to be higher among children vaccinated before 14 or 15 months of age and to increase with time since vaccination.

METHODS

An ongoing study at the Northern California Kaiser Permanente Medical Care Program is evaluating vaccine efficacy in 7585 children vaccinated with Varivax in 1995, when they were between 12 and 23 months of age. Cases of chickenpox are identified by telephone interviews with each child's parent(s) every 6 months. Mean age at varicella onset and mean time from vaccination to onset were calculated on the basis of age, in months, at vaccination. Logistic regression was used to test for trend, and the chi2 test was used to test for differences in rates of breakthrough varicella by age.

RESULTS

Over the first 8 years of the study, a total of 1161 cases of breakthrough varicella were reported, for an average rate of 21.7 cases/1000 person-years. Vaccine effectiveness was 83.6% at year 8. The rate of breakthrough varicella did not change for each additional month of age at vaccination (P = .864), and no difference in the rate of breakthrough varicella was found between children vaccinated at <15 months of age and those vaccinated at > or =15 months of age.

CONCLUSIONS

Our data do not show a difference in vaccine effectiveness with age at vaccination and thus support the current recommendations for initial vaccination between 12 and 18 months of age.

Reducing the dose of smallpox vaccine reduces vaccine-associated morbidity without reducing vaccination success rates or immune responses

BACKGROUND

When the decision was made to prepare for a deliberate release of smallpox, the United States had approximately 15 million doses of Wyeth Dryvax vaccine, which was known to induce significant morbidity when used undiluted; Sanofi Pasteur, Inc., later identified approximately 85 million additional doses in storage.

METHODS

Eleven vaccine-dose groups, each with 30 vaccinia-naive subjects, were given diluted Dryvax vaccine or 1 of 2 lots of Sanofi Pasteur smallpox vaccine and were evaluated for vaccination success rates, morbidity, and immune responses.

RESULTS

Estimated doses of 10(6.6)-10(8.2) pfu of virus/mL induced major reactions (or "takes") in 93%-100% of subjects in each dose group. No differences in vaccination take rates, lesion size, erythema, and induration or in serum neutralizing-antibody response were detected between the groups. However, systemic reactogenicity and missed activities were significantly lower for the vaccine groups given doses of 10(6.6)-10(7.2) pfu/mL than for those given doses of 10(7.6)-10(8.2) pfu/mL.

CONCLUSIONS

These findings support the use of a higher dilution of Wyeth Dryvax vaccine and Sanofi Pasteur smallpox vaccine, given that the resulting morbidity should be significantly lower without loss of vaccine effectiveness. A plan for use of higher dilutions would create an enormous stockpile of vaccine.

Effectiveness of heptavalent pneumococcal conjugate vaccine in children younger than 5 years of age for prevention of pneumonia: updated analysis using World Health Organization standardized interpretation of chest radiographs

BACKGROUND

A World Health Organization (WHO) working group in 2001 developed a method for standardizing interpretation of chest radiographs in children for epidemiologic purposes. We reevaluated radiographs from the Kaiser Permanente Pneumococcal Efficacy trial using this method.

METHODS

Seven-valent pneumococcal conjugate vaccine was evaluated in a randomized, controlled study including 37,868 infants. Effectiveness against pneumonia was previously evaluated using the original treating radiologist reading. There were 2841 sets of radiographs from this trial and all available radiographs were scanned and read blindly by 2 WHO crosstrained readers (A and B); discordance between the 2 primary readers was resolved through a consensus reading by an adjudicating panel of 2 radiologists.

RESULTS

Of the 2841 radiographs, 2446 were available for scanning and were reviewed using WHO-defined descriptive categories. Two hundred fifty of the 2446 radiographs were read as positive by both readers. An additional 129 were read as positive by reader A only and 142 by reader B only for a total of 521 radiographs that were read as positive by one or both of the reviewers. The concordance rate between the 2 reviewers was 250 of 521 (48%). Of the 271 discordant radiographs, 45 of 129 (34.9%) of reader A and 66 of 142 (46.5%) for reader B were finalized as positive by the adjudicating panel. Overall, 361 radiographs were finalized as positive (12.7%). With these 361 images as the standard, the sensitivity and specificity of reader A were 82% and 97%, respectively, and for reader B, 88% and 97%, respectively. Kappa between the 2 readers was 0.58. Of 25 control radiographs read as positive by both A and B, 80% were also read as positive by the panel and all 25 control negative radiographs were read as negative by the panel. Using original readings by point-of-care radiologists, efficacy against first episode of radiograph confirmed pneumonia was 17.7% (95% confidence interval [CI] = 4.8-28.9%) in intent-to-treat and 20.5% (95% CI = 4.4-34%) in per protocol. Using the WHO method, the efficacy against first episode of radiograph confirmed pneumonia adjusting for age, gender and year of vaccination of 25.5% (95% CI = 6.5-40.7%, P = 0.011) for intent-to-treat and 30.3% (95% CI = 10.7-45.7%, P = 0.0043) for per protocol.

CONCLUSION

Using WHO criteria for reading of radiographs increased point estimates of vaccine efficacy presumably as a result of improved specificity.

Encephalopathy after whole-cell pertussis or measles vaccination: lack of evidence for a causal association in a retrospective case-control study

BACKGROUND

Whole-cell pertussis (wP) and measles vaccines are effective in preventing disease but have also been suspected of increasing the risk of encephalopathy or encephalitis. Although many countries now use acellular pertussis vaccines, wP vaccine is still widely used in the developing world. It is therefore important to evaluate whether wP vaccine increases the risk of neurologic disorders.

METHODS

A retrospective case-control study was performed at 4 health maintenance organizations. Records from January 1, 1981, through December 31, 1995, were examined to identify children aged 0 to 6 years old hospitalized with encephalopathy or related conditions. The cause of the encephalopathy was categorized as known, unknown or suspected but unconfirmed. Up to 3 controls were matched to each case. Conditional logistic regression was used to analyze the relative risk of encephalopathy after vaccination with diphtheria-tetanus-pertussis (DTP) or measles-mumps-rubella (MMR) vaccines in the 90 days before disease onset as defined by chart review compared with an equivalent period among controls indexed by matching on case onset date.

RESULTS

Four-hundred fifty-two cases were identified. Cases were no more likely than controls to have received either vaccine during the 90 days before disease onset. When encephalopathies of known etiology were excluded, the odds ratio for case children having received DTP within 7 days before onset of disease was 1.22 (95% confidence interval [CI] = 0.45-3.31, P = 0.693) compared with control children. For MMR in the 90 days before onset of encephalopathy, the odds ratio was 1.23 (95% confidence interval = 0.51-2.98, P = 0.647).

CONCLUSIONS

In this study of more than 2 million children, DTP and MMR vaccines were not associated with an increased risk of encephalopathy after vaccination.

The safety and immunogenicity of a quadrivalent measles, mumps, rubella and varicella vaccine in healthy children: a study of manufacturing consistency and persistence of antibody

BACKGROUND

This clinical trial was conducted to demonstrate that each of 3 consistency lots of a combined measles, mumps, rubella and varicella vaccine (MMRV) would be well tolerated, induce clinically acceptable and similar immune responses to each antigen and induce immune responses similar to measles, mumps and rubella vaccine (MMR) administered concomitantly with varicella vaccine (V). An additional objective was to evaluate the persistence of antibodies 1 year postvaccination.

METHODS

Study participants 12 to 23 months of age received a single injection of either one of 3 consistency lots of MMRV or MMR + V administered at separate injection sites.

RESULTS

A total of 3,928 healthy children were enrolled at study sites in the United States and Canada. Immune responses to measles, mumps, rubella and varicella in children immunized with each of 3 lots of MMRV were similar and the combined response to all 3 lots was comparable to that of the control group. The 1-year antibody persistence rates for measles, mumps, rubella and varicella viruses were each greater than 95% and comparable among the recipients of the 3 consistency lots of MMRV and the control group. All vaccines were generally well tolerated during the 42 days after vaccination and the overall incidence of adverse experiences was comparable between recipients of MMRV and MMR + V. Rates of fever (temperature >or=38.9 degrees C oral equivalent or tactile) were greater in recipients of MMRV than in recipients of MMR + V (39.1% versus 33.1%, P = 0.001). Fevers were transient and there was no difference in the incidence of febrile seizures.

CONCLUSIONS

MMRV was generally well tolerated and had comparable immunogenicity and overall safety profiles to MMR + V administered concomitantly. Long-term persistence of antibodies after receipt of MMRV is expected based on similar antibody titers against all 4 antigens 1 year postvaccination compared with recipients of MMR and V.

Safety and immunogenicity of a measles, mumps, rubella and varicella vaccine given with combined Haemophilus influenzae type b conjugate/hepatitis B vaccines and combined diphtheria-tetanus-acellular pertussis vaccines

BACKGROUND

A study was conducted to assess administration of a combination measles, mumps, rubella and varicella vaccine (MMRV) with other childhood vaccines.

METHODS

In this open, multicenter trial, 1915 healthy children ages 12-15 months were randomized into 3 groups: group 1, MMRV, combined Haemophilus influenzae type b conjugate-hepatitis B vaccines (Hib/HepB) and combined diphtheria-tetanus-acellular pertussis vaccines (DTaP) concomitantly; group 2, MMRV followed by Hib/HepB and DTaP 42 days later; group 3, MMR and varicella vaccine followed by Hib/HepB and DTaP 42 days later.

RESULTS

Antibody responses to measles, mumps, rubella, varicella, Hib, HepB, diphtheria and tetanus were similar between groups 1 and 2 (all >95%, except varicella, 89.7% in group 1 and 90.9% in group 2). Pertussis toxin and filamentous hemagglutinin responses were significantly lower in group 1 than in group 2 (group 1, 74.1 and 67.1%; group 2, 90.4 and 86.8%, respectively). An exploratory analysis suggested that the difference in and pertussis toxin and filamentous hemagglutinin responses was likely the result of study design rather than interference among vaccine components because the groups differed in age of receipt of DTaP (group 1, approximately 12 months; group 2, approximately 13.5 months). When the groups were matched for age, sample size was sufficient for comparison only in children > or =13.5 months old. Pertussis toxin and filamentous hemagglutinin responses were similar in these children. The safety profiles for each vaccination regimen were comparable.

CONCLUSIONS

The immunogenicity data support concomitant administration of MMRV with Hib/HepB. Limited data from an exploratory analysis indicate that MMRV can be administered concomitantly with DTaP. Concomitant administration of MMRV, Hib/HepB and DTaP is well-tolerated.

Impact of the use of heptavalent pneumococcal conjugate vaccine on disease epidemiology in children and adults

Pneumococcal conjugate vaccine was introduced for routine use in infants and toddlers in the United States in March 2000. We report on the impact of the introduction of this vaccine on disease epidemiology in young children as well as secondary effects due to herd immunity in unvaccinated children and adults. As of March 2003, 157,471 children had received one or more doses of PNCV7, but only 24% of those less than two years of age received all four doses as a result of shortages of vaccine. During the last year of observation, no cases of vaccine serotype disease were seen in children less than one year of age compared with an incidence ranging between 51.5 and 98.2 cases/100,000 person years (16-34 cases per year) in the years before vaccine introduction. Similar reductions were seen in children less than five years of age. There was no evidence of any concomittant increase in pneumococcal disease caused by non-vaccine serotypes. High-level resistance of pneumococci to penicillin fell from a peak of 15% in year 2000 to 5% in the first half of 2003.

A personnel time-motion study of intranasal influenza vaccination in healthy children

Vaccinating millions of Americans depends, in part, on short vaccination times. During two intranasal influenza vaccine trials, times for six vaccination steps were recorded for 497 children. The total of mean times for the steps was 115 s, almost half spent explaining the vaccine and intranasal delivery. Intranasal influenza vaccination time showed little variation by patient age, was comparable to reported intramuscular vaccination times, and was a small fraction of the visit time. Total family visit time decreased by 64 s if the youngest child was receiving a second dose. Alternative delivery systems (e.g., group visits) are needed to take advantage of short vaccination times.

Active telephone surveillance to evaluate adverse events among civilian smallpox vaccine recipients

OBJECTIVE

Better characterize and monitor adverse events following Dryvax vaccinia vaccination in civilian health care workers and other first responders.

DESIGN

Telephone interviews to ascertain adverse events experienced.

RESULTS

Eight hundred twenty-five vaccinees, including 44 in the comparison group, were interviewed. At 10 days, 71.4% reported blisters, 35.1% reported bumps at the vaccination site, 48.5% swelling, 47.3% scab, tiredness/lethargy/fatigue (43.6%), headache (34.2%), lymph node swelling/tenderness (28.5%), muscle pain (23.1%), chills (14.4%), joint pain 11.8%, and fever >100 degrees F (12.5%). The 12.5% reported missing work because of vaccine adverse events. Most adverse events were anticipated and of short duration.

Dose-response study of a quadrivalent measles, mumps, rubella and varicella vaccine in healthy children

BACKGROUND

A combined measles, mumps, rubella and varicella (MMRV) vaccine would facilitate universal immunization against 4 diseases by decreasing the number of injections and thus enhancing compliance and coverage rates. If a second dose of varicella vaccine were to be recommended, MMRV could be used to administer a routine second dose of M-M-RII with the added advantage of boosting varicella-zoster virus (VZV) antibody titers.

METHODS

Subjects 12-23 months of age received a single injection of 1 of 3 lots of an MMRV vaccine (ProQuad) containing high, middle or low VZV potency, or VARIVAX given concomitantly with M-M-RII. Recipients of MMRV received a second injection of MMRV approximately 90 days later.

RESULTS

We enrolled 1559 subjects in the study. Antibody response rates to VZV 6 weeks after 1 injection of high potency MMRV (88.6%) or 2 injections of MMRV of any varicella potency (99.7-100%) were similar to the response rates after concomitant administration of M-M-RII and VARIVAX (93.1%). The second injection of MMRV boosted VZV antibody titers. Antibody responses to measles, mumps and rubella were >or=98%, similar to the control, after 1 or 2 injections of MMRV. MMRV was generally well-tolerated during the 42 days after vaccination.

CONCLUSIONS

One injection of high potency MMRV resulted in antibody responses to the 4 vaccine components equivalent to those found after concomitant administration of M-M-RII and VARIVAX. A second injection of MMRV resulted in a significant boost in VZV antibody. This boost may translate into enhanced immunogenicity against varicella, which is known to correlate with increased protection.

Evaluation of a quadrivalent measles, mumps, rubella and varicella vaccine in healthy children

BACKGROUND

A quadrivalent measles, mumps, rubella and varicella vaccine would facilitate universal immunization against all 4 diseases, improve compliance and immunization rates and decrease the number of injections given to children and visits to physicians' offices.

OBJECTIVES

To evaluate 1- and 2-dose regimens of a combined measles, mumps, rubella and varicella vaccine (ProQuad, referred to as MMRV) manufactured with a varicella component of increased potency.

METHODS

In this partially blind, multicenter study, 480 healthy 12- to 23-month-old children were randomized to receive either MMRV and placebo or M-M-RII and VARIVAX. Injections were given concomitantly at separate sites. Subjects randomized to receive MMRV and placebo received a second dose of MMRV 90 days later. Subjects were followed for 42 days after each vaccination for adverse experiences. Immunogenicity was evaluated 6 weeks after each vaccination.

RESULTS

Measles-like rash and fever during days 5-12 were more common after the first dose of MMRV (rash, 5.9%; fever, 27.7%) than after M-M-RII and VARIVAX (rash, 1.9%; fever, 18.7%). The incidence of other adverse events were similar between groups. Response rates were >90% to all vaccine components in both groups. Geometric mean titers to measles and mumps were significantly higher after 1 dose of MMRV than after administration of M-M-RII and VARIVAX. The second dose of MMRV elicited slight to moderate increases in measles, mumps and rubella antibody titers and a substantial increase in varicella antibody titer (from 13.0 to 588.1 glycoprotein antigen-based enzyme-linked immunosorbent assay units/mL).

CONCLUSION

A 1- or 2-dose regimen of MMRV is generally well-tolerated when administered to 12- to 23-month-old children and has a safety and immunogenicity profile similar to that of M-M-RII and VARIVAX administered concomitantly.

Active surveillance of vaccine safety: a system to detect early signs of adverse events

BACKGROUND

There currently are no population-based systems in the United States to rapidly detect adverse events after newly introduced vaccines. To evaluate the feasibility of developing such systems, we used 5 years of data from 4 health maintenance organizations within the Centers for Disease Control and Prevention (CDC) Vaccine Safety Datalink.

METHODS

Within every year, each week's vaccinated children were followed for 4 weeks, and rates of adverse events were compared with rates among children of similar ages before the introduction of the new vaccine. We assessed risks for intussusception after rotavirus vaccination and risks for fever, seizures, and other neurologic adverse events after the change from whole cell diphtheria-tetanus-pertussis (DTPw) to acellular DTP vaccine (DTPa). We used sequential probability ratio testing, adjusted for age, sex, calendar time, season, and HMO, and with a stopping value based on the probability of an adverse event under the null hypothesis and under a preset alternative hypothesis.

RESULTS

We detected an increase in intussusception after 2589 vaccine doses of rotavirus vaccine, about the same time initial reports of intussusception were made to the Vaccine Adverse Events Reporting System. Decreases in risk for fever, seizures, and other abnormal neurologic events became detectable within 12 weeks, 42 weeks, and 18 months, respectively, after the change from DTPw to DTPa.

CONCLUSIONS

We conclude that it is feasible to develop systems for rapid and routine population-based assessments of new vaccine safety.

Safety, Efficacy, and Effectiveness of Live, Attenuated, Cold‐Adapted Influenza Vaccine in an Indicated Population Aged 5–49 Years

BACKGROUND

Three important studies have supported licensure of live, attenuated, cold-adapted influenza vaccine (CAIV-T [FluMist; MedImmune Vaccines]): (1) a pediatric efficacy trial involving children 15-71 months of age, (2) a large safety study of medically attended events occurring among children 1-17 years of age, and (3) an effectiveness trial involving healthy working adults 18-64 years of age.

METHODS

During the United States Food and Drug Administration (FDA) review for the approval of CAIV-T for use in healthy persons, additional subgroup analyses were conducted to evaluate the safety, efficacy, and effectiveness of the vaccine, by use of various age subsets not prespecified by the original protocols. CAIV-T is currently approved by the FDA for use in healthy persons 5-49 years of age. In this article, we present data from some of the aforementioned subanalyses.

RESULTS

The efficacy of CAIV-T in children >or=5 years of age (age range of the children in year 1 of the study, 60-71 months; age range of the children in year 2 of the study, 60-83 months) was similar to that reported for the entire cohort in year 1 (90.6%; 95% confidence interval [CI], 70.3%-97.1%). In year 2 of the study, efficacy was 86.9% (95% CI, 70.8%-94.1%), despite the presence of antigenically drifted influenza type A/Sydney/5/97 (H3N2), which caused most illnesses that occurred in year 2. Safety outcomes for children 5-17 years of age revealed no significant difference between vaccine recipients and placebo recipients, with regard to acute respiratory events, acute gastrointestinal events, systemic bacterial infection, or rare events possibly related to influenza. Effectiveness among adults 18-49 years of age was similar to that reported for the entire cohort--for example, for occurrence of severe febrile illness, there was a 19.5% reduction (P=.02) in adults.

CONCLUSIONS

The present reanalysis summarizes data on the indicated uses for CAIV-T in the indicated population aged 5-49 years.

[Clinical effectiveness of seven-valent pneumococcal conjugate vaccine (Prevenar) against invasive pneumococcal diseases: prospects for children in France]

A seven-valent pneumococcal polysaccharide-CRM197 carrier protein conjugate vaccine (PNC7V; Prevenar, Wyeth, Paris) targets the serotypes (belonging to serogroups 14, 6, 19, 18, 23, 9, and 4) most often responsible for invasive pneumococcal disease (IPD) among children. A randomized, controlled, double-masked study among 37,868 children in northern California (Northern California Kaiser Permanente, USA) provided a per protocol vaccine efficacy value of 97.7% against invasive pediatric IPD due to the vaccine serotypes. The PNC7V vaccine was registered by the European Agency for the Evaluation of Medicinal Products (EMEA) in October 2000; a favorable "Community Marketing Decision" under the Centralized Procedure was granted in February 2001. PNC7V was recommended for most infants by the Conseil Supérieur d'Hygiène Publique de France in March 2002, on the advice of the Comité Technique des Vaccinations, as S. pneumoniae in children less than 2 years of age is the primary cause of bacterial meningitis and of mortality associated with community-acquired bacterial infections. The theoretical coverage of the vaccine towards pneumococcal invasive disease in France is about 80%, which represents one of the best serotype coverage estimates in Europe, and vaccines serotypes account for 90% of penicillin-nonsusceptible strains. Distinctive characteristics in France in terms of epidemiology, life style, and therapeutic attitudes justify a precise follow up of the consequences of the vaccination on a national level during the coming years. Hence, surveillance programs have been established: (i) to ascertain the future impact of large-scale PNC7V vaccination on invasive pneumococcal disease incidence, (ii) to follow the evolution of carriage and ecology of the pneumococcus, and (iii) to establish an active "vaccinovigilance".

Lack of association between hepatitis B birth immunization and neonatal death: a population-based study from the vaccine safety datalink project

BACKGROUND

There have been no population-based studies of the potential association between neonatal death and newborn immunization with hepatitis B vaccine (HBV).

METHODS

As part of the Vaccine Safety Datalink Project, we defined a birth cohort at Southern and Northern California Kaiser Permanente Health Plans of more than 350,000 live births from 1993 to 1998 and ascertained all deaths occurring under 29 days of age. We compared the proportions of deaths among birth HBV-vaccinated and unvaccinated newborns and reviewed the causes and circumstances of their deaths. We performed detailed clinical reviews of all HBV-vaccinated neonates who died and a sample of unvaccinated neonates who died and who were matched to vaccinated deaths for days of life, sex, birth year and site of care. To avoid confounding, we categorized the causes of death as either "expected" or "unexpected" and performed a stratified analysis to compare mortality with immunization status.

RESULTS

There were 1363 neonatal deaths during the study period. Whereas 67% of the entire birth cohort received HBV at birth, only 72 (5%) of the neonates who died were HBV-vaccinated at birth (P < 0.01). We found no significant difference in the proportion of HBV-vaccinated (31%) and unvaccinated (35%) neonates dying of unexpected causes (P = 0.6). Further we could not identify a plausible causal or temporal relationship between HBV administration and death for the 22 vaccinated neonates who died unexpectedly.

CONCLUSIONS

A relationship between HBV and neonatal death was not identified.

Postlicensure surveillance for pneumococcal invasive disease after use of heptavalent pneumococcal conjugate vaccine in Northern California Kaiser Permanente

OBJECTIVE

To assess the direct and indirect effects of the introduction of routine use of pneumococcal conjugate vaccine in infants and toddlers at risk for invasive disease caused by vaccine serotypes and nonvaccine serotypes in vaccinated children and unvaccinated children of the same age. Secondary objectives included determination of the risk of pneumococcal infections in unvaccinated older children and adults in the same population and the impact of vaccine introduction on patterns of antimicrobial resistance.

METHODS

Northern California Kaiser Permanente provides integrated comprehensive care to 3.1 million people and has an annual birth cohort of 38,000 infants. Microbiology services use a regional laboratory. Automated laboratory results, immunization records as well as diagnoses for inpatient and outpatient utilization are available from clinical data bases. Beginning in April 2000, the heptavalent pneumococcal conjugate (PNCV7) vaccine was introduced into routine use in the Northern California Kaiser Permanente population. Cases of invasive pneumococcal disease were identified from the automated hospital diagnosis as well as laboratory databases for all individuals, vaccinees and nonvaccinees, inpatient and outpatient. For the purpose of these analyses, pneumococcal invasive disease was defined as a positive culture from a normally sterile site.

RESULTS

As of March 2003, 157,471 children had received 1 dose or more of PNCV7, but only 24% of those <2 years of age received all 4 doses as a result of shortages of vaccine. During the last year of observation, no cases of vaccine serotype disease were seen in children <1 year of age compared with an incidence ranging between 51.5 and 98.2 cases per 100,000 person-years (16-34 cases per year) in the years before vaccine introduction. Similar reductions were seen in children <5 years of age. There was no evidence of any concomitant increase in pneumococcal disease caused by nonvaccine serotypes. High level resistance of pneumococci to penicillin fell from a peak of 15% in 2000 to 5% in the first half of 2003. Similar trends were seen for other antibiotics.

CONCLUSION

The PNCV7 vaccine is highly effective in reducing the burden of pneumococcal disease in children <5 years of age, and there is evidence of a herd effect as well as a decrease in the antibiotic resistant in strains causing disease. For invasive disease, there is no current evidence of serotype replacement.

A post-licensure evaluation of the safety of inactivated hepatitis A vaccine (VAQTA, Merck) in children and adults

BACKGROUND

Hepatitis A is a major cause of epidemic hepatitis in the US. In pre-licensure trials, inactivated hepatitis A vaccine (HAV, VAQTA, Merck) was shown to be generally well-tolerated and effective in inducing immunity to hepatitis A infection in adults and children over 2 years of age. Following the licensure of this vaccine, we began a Phase IV safety evaluation in adults and in children over 2 years of age.

METHODS

Safety was assessed by comparing the rates of diagnoses in clinic, emergency and hospital utilization. From April 1997 to December 1998, rates of diagnoses within 30 days for the clinic and emergency setting and 60 days for hospitalization were compared with unexposed follow-up time in the same individuals both before receipt of vaccine and after the 60 days interval post-vaccination.

RESULTS

There were a total of approximately 2000 comparisons between the risk and "before" or "after" period. Among them, 106 were found to have statistically significant differences in rates (30 elevated, 76 lowered). Among children/adolescents (2-17 year-old), in the hospitalization category, the only statistically significant elevated risk found was "elective procedures", as compared with both "before" and "after" periods. In the outpatient visit category for children and adolescents, elevated risks were found for consultation/general medicine/exam when compared with both "before" and "after" periods, and ganglion and viral warts when compared with either "before" or "after" period. Among adults (> or =18 year-old), in the outpatient visit category, a statistically significant elevated relative risk was seen for diarrhea/gastroenteritis for both "before" and "after" periods. There were additionally 17 diagnostic categories that showed a statistically significantly elevated relative risk compared with either "before" or "after" period. Except for diarrhea/gastroenteritis, the other eight events were elevated only in one comparison (either "before" or "after"). These eight elevated relative risks might be explained by chance resulting from multiple comparison or seasonal variations. There were no serious adverse events judged by the investigator to be associated with HAV.

CONCLUSION

In this large Phase IV evaluation of the safety of HAV, the vaccine appeared to be generally well-tolerated. These data support the continued routine use of HAV for vaccination in children and adults.

Medically recorded allergies and the risk of childhood acute lymphoblastic leukaemia

Data on five allergic conditions were abstracted from the medical records of 180 cases of childhood acute lymphoblastic leukaemia (ALL) and 718 matched controls. Odds Ratios (OR) and 95% Confidence Intervals (CI) were estimated for composite variables and for individual allergies using conditional logistic regression modelling. Allergies were divided into late and early diagnoses (those made within the year before the matched case's ALL diagnosis and those made earlier, respectively). Among the early diagnoses, atopy or hives was significantly associated with ALL (OR=2.20; 95% CI: 1.16-4.16). Significant associations were found for late diagnoses of atopy or hives (OR=3.78; 95% CI: 1.00-14.29) and of asthma (OR=3.10; 95% CI: 1.39-6.95). None of the other allergic conditions were associated with ALL. These results are contrary to those of prior studies of childhood ALL and allergy.

Ten year follow-up of healthy children who received one or two injections of varicella vaccine

BACKGROUND

The rate of varicella and persistence of varicella antibody after a one dose vs. a two dose regimen of varicella virus vaccine live Oka/Merck (VARIVAX; Merck & Co., Inc., West Point, PA) in approximately 2000 children were compared during a 9- to 10-year follow-up period.

METHODS

Children 12 months to 12 years of age with a negative history of varicella were randomized in late 1991 to early 1993 to receive either one or two injections of varicella vaccine given 3 months apart. Subjects were actively followed for varicella, any varicella-like illness or zoster and any exposures to varicella or zoster on a yearly basis for 10 years after vaccination. Persistence of varicella antibody was measured yearly for 9 years.

RESULTS

Most cases of varicella reported in recipients of one or two injections of vaccine were mild. The risk of developing varicella >42 days postvaccination during the 10-year observation period was 3.3-fold lower (P < 0.001) in children who received two injections than in those who received one injection (2.2% vs. 7.3%, respectively). The estimated vaccine efficacy for the 10-year observation period was 94.4% for one injection and 98.3% for two injections (P < 0.001). Measurable serum antibody persisted for 9 years in all subjects.

CONCLUSIONS

Administration of either one or two injections of varicella vaccine to healthy children results in long term protection against most varicella disease. The two dose regimen was significantly more effective than a single injection.

Safety of cold-adapted live attenuated influenza vaccine in a large cohort of children and adolescents

OBJECTIVE

To determine the safety of cold-adapted trivalent intranasal influenza virus vaccine (CAIV) in children and adolescents.

STUDY DESIGN

A randomized, double blind, placebo-controlled safety trial in healthy children age 12 months to 17 years given CAIV (FluMist; MedImmune Vaccines, Inc.) or placebo (randomization, 2:1). Children <9 years of age received a second dose of CAIV or placebo 28 to 42 days after the first dose. Enrolled children were then followed for 42 days after each vaccination for all medically attended events. Prespecified outcomes included 4 prespecified diagnostic groups and 170 observed individual diagnostic categories. The relative risk and the 2-sided 90% confidence interval were calculated for each diagnostic group and individual category by clinical setting, dose and age. More than 1500 relative risk analyses were performed.

RESULTS

A total of 9689 evaluable children were enrolled in the study. Of the 4 prespecified diagnostic categories (acute respiratory tract events, systemic bacterial infection, acute gastrointestinal tract events and rare events potentially associated with wild-type influenza), none was associated with vaccine. Of the biologically plausible individual diagnostic categories, 3, acute gastrointestinal events, acute respiratory events and abdominal pain, had different analyses that demonstrated increased and decreased relative risks, making their association with the vaccine unlikely. For reactive airway disease a significant increased relative risk was observed in children 18 to 35 months of age with a relative risk of 4.06 (90% confidence interval, 1.29 to 17.86) in this age group. The individual diagnostic categories of upper respiratory infection, musculoskeletal pain, otitis media with effusion and adenitis/adenopathy had at least one analysis that achieved a significant increased risk ratio. All of these events were infrequent.

CONCLUSION

CAIV was generally safe in children and adolescents. The observation of an increased risk of asthma/reactive airway disease in children <36 months of age is of potential concern. Further studies are planned to evaluate the risk of asthma/reactive airway disease after vaccine.

Post-marketing evaluation of the short term safety of COMVAX®

We report an evaluation of the short-term safety of a pediatric bivalent combination vaccine containing RECOMBIVAXHB and Liquid PedvaxHIB, COMVAX. Safety was assessed through identification of medical utilization; potential adverse events were identified through computerized clinical databases for deaths, hospitalizations, emergency room visits, and outpatient clinic visits. We calculated relative risks whenever there was at least one diagnosis-specific event in the risk period following vaccination and compared the rates in specific time windows following vaccination with rates at 31-60 days following vaccination and also with rates in a historical cohort of children. A total of 27,802 doses of COMVAX were administered, with 127 separate adverse event codes with statistically significant elevated risks, and 66 codes with significantly decreased risks. Most potentially serious diagnoses appeared in four major categories: "Respiratory Events"; "Gastroenteritis"; "Adverse Effect of Medicinal and Biological Substance, NOS"; and "Fever". There was no consistent pattern to indicate increased risks for serious respiratory or gastrointestinal illness. For fever, most of the findings appeared to be explained by changes in data collection or by concomitant vaccination with M-M-R(-)II. There was an increased risk for fever hospitalizations following shot 1. The total number of children hospitalized with fever was seven out of 12,468 children; all recovered fully. In this study population of 27,802 vaccine recipients, COMVAX appeared to have a favorable safety profile.

Safety of thimerosal-containing vaccines: a two-phased study of computerized health maintenance organization databases

OBJECTIVE

To assess the possible toxicity of thimerosal-containing vaccines (TCVs) among infants.

METHODS

A 2-phased retrospective cohort study was conducted using computerized health maintenance organization (HMO) databases. Phase I screened for associations between neurodevelopmental disorders and thimerosal exposure among 124 170 infants who were born during 1992 to 1999 at 2 HMOs (A and B). In phase II, the most common disorders associated with exposure in phase I were reevaluated among 16 717 children who were born during 1991 to 1997 in another HMO (C). Relative risks for neurodevelopmental disorders were calculated per increase of 12.5 micro g of estimated cumulative mercury exposure from TCVs in the first, third, and seventh months of life.

RESULTS

In phase I at HMO A, cumulative exposure at 3 months resulted in a significant positive association with tics (relative risk [RR]: 1.89; 95% confidence interval [CI]: 1.05-3.38). At HMO B, increased risks of language delay were found for cumulative exposure at 3 months (RR: 1.13; 95% CI: 1.01-1.27) and 7 months (RR: 1.07; 95% CI: 1.01-1.13). In phase II at HMO C, no significant associations were found. In no analyses were significant increased risks found for autism or attention-deficit disorder.

CONCLUSIONS

No consistent significant associations were found between TCVs and neurodevelopmental outcomes. Conflicting results were found at different HMOs for certain outcomes. For resolving the conflicting findings, studies with uniform neurodevelopmental assessments of children with a range of cumulative thimerosal exposures are needed.

Serotype distribution and antimicrobial resistance patterns in Streptococcus pneumoniae isolates from hospitalized pediatric patients with respiratory infections in Shanghai, China

BACKGROUND

Surveillance for pneumococcal respiratory illness was conducted in children hospitalized at Affiliated Pediatric Hospital of Fudan University in Shanghai from August 2000 to August 2001.

METHODS

Sputum cultures were obtained from pediatric patients admitted with pneumonia or respiratory distress by tracheal aspirate. Blood cultures were also performed on a subset of patients. All pneumococcal isolates were serotyped and tested for antibiotic susceptibility. In addition clinical information on the patients including prior antibiotic history was abstracted. Streptococcus pneumoniae tracheal isolations were attempted in a total of 1013 pediatric patients hospitalized during this period. Among these samples 112 specimens were S. pneumoniae-positive. These positive isolates underwent serotyping and antibiotic susceptibility testing.

RESULTS

Five serotypes (19F, 23F, 6A, 14, 6B) of S. pneumonia accounted for 81% (91 of 112 cases). Other serotypes accounted only for 12% (13 of 112 cases), and 7% (8 of 112 cases) of isolates could not be typed by quelling test. Only one blood culture isolate was positive, probably reflecting the frequent use of antibiotic treatment before hospitalization. Fifty-one and 8.0% of isolates had intermediate and high level penicillin resistance, respectively. Fifty-eight percent were resistant to ampicillin, 6.6% to cefazolin, 25.0% to cefaclor, 6.6% to ceftriaxone, 85.7% to erythromycin, 66.7% to clindamycin and 28.2% to chloramphenicol. Among 66 isolates that were not susceptible to penicillin, serotype 19F was the most common, followed by 23F and 14.

CONCLUSION

S. pneumoniae is a common cause of respiratory illness requiring hospitalization in young children in Shanghai, with antibiotic resistance increasingly common. Five serotypes account for most disease.

Impact of the introduction of a combined Haemophilus B conjugate vaccine and hepatitis B recombinant vaccine on vaccine coverage rats in a large West Coast health maintenance organization

We evaluated the effect of introduction of a combined hepatitis B-Haemophilus influenzae b vaccine on vaccine coverage rates in a large health maintenance organization and found a modest improvement in up-to-date immunization status.

Safety and efficacy of the seven-valent pneumococcal conjugate vaccine: evidence from Northern California

Pneumococcal disease remains a significant cause of morbidity among young children. A large-scale efficacy trial in the Northern California Kaiser Permanente system (the KP trial) demonstrated that a seven-valent conjugate vaccine (PCV) is safe and immunogenic in young children and effective in preventing both invasive pneumococcal disease caused by vaccine serotypes (97.4% efficacy) and episodes of otitis media (7.0% efficacy). Since the publication of the results of the KP trial in 2000, we have performed an additional analysis on the safety, immunogenicity, and efficacy of the vaccine in low birth weight (LBW) and preterm (PT) infants, and have examined the efficacy of the vaccine during 1 year of wide-scale post-licensure use. The vaccine was at least as immunogenic in LBW and PT infants as in normal-weight, full-term infants and was 100% effective, although the LBW and PT infants had higher rates of adverse events such as redness and swelling. LBW and PT infants receiving pneumococcal vaccine also had higher rates of adverse events, such as hives, than those receiving control meningococcal vaccine, but these reactions were not severe. When the PCV was used in the general population, the efficacy remained high and there was no corresponding increase in disease caused by nonvaccine serotypes. There was also evidence that vaccine administration led to herd immunity. Febrile illness was the only adverse event seen more frequently after vaccine administration than during a control period.

CONCLUSION

the seven-valent conjugate vaccine is safe and effective for use in the general population.

Is household antibiotic use a risk factor for antibiotic-resistant pneumococcal infection?

We used microbiology and pharmacy data from health-maintenance organizations to determine whether antibiotic use by a household member increases the risk of penicillin-non-susceptible pneumococcal disease. Though it has been well established that an individual's antibiotic use increases one's risk of antibiotic-resistant infection, it is unclear whether the risk is increased if a member of one's household is exposed to antibiotics. We therefore conducted a case-control study of patients enrolled in health maintenance organizations in Western Washington and Northern California. Cases were defined as individuals with penicillin-non-susceptible pneumococcal infection; controls were individuals with penicillin-susceptible pneumococcal infection. Socioeconomic variables were obtained by linking addresses with 1997 census block group data. One-hundred and thirty-four cases were compared with 798 controls. Individual antibiotic use prior to diagnosis increased the odds of penicillin non-susceptibility, with the strongest effect seen for beta-lactam use within 2 months (OR 1.8, 95% CI 1.2, 2.8). When household antibiotic use by persons other than the patient were considered, at 4 months prior to diagnosis there was a trend towards an association between penicillin non-susceptibility and beta-lactam antibiotic use, and a possible association in a small subgroup of patients with eye and ear isolates. However, no significant overall pattern of association was seen. We conclude that though antibiotic use of any kind within 2 months prior to diagnosis is associated with an increased risk of penicillin-non-susceptible pneumococcal disease, there is no significant overall pattern of association between household antibiotic use and penicillin-non-susceptible pneumococcal infection.

Efficacy, immunogenicity and safety of heptavalent pneumococcal conjugate vaccine in low birth weight and preterm infants

OBJECTIVE

To determine the efficacy, immunogenicity and safety of the heptavalent CRM197 pneumococcal conjugate vaccine (PCV) in low birth weight (LBW) and preterm (PT) infants against invasive pneumococcal disease caused by vaccine types.

METHODS

In a randomized double blind trial of 37,868 infants given either PCV or meningococcal type C conjugate vaccine (MCV), 1756 infants <750 g <2500 g (LBW) and 4340 infants from 32 to <38 weeks old (PT) were identified. Risk of invasive pneumococcal disease in LBW and PT infants was compared with risk in normal birth weight (NBW) and full term (FT) infants. Local and systemic events observed within 48 h of recent vaccine were assessed by telephone interviews and similar comparisons made. Premature infant Emergency Department visits and hospitalization were also identified and compared with FT and NBW infants.

RESULTS

Initiation of immunization and intervals between doses were similar for all groups. The risk ratio for invasive pneumococcal diseases for LBW infants compared with NBW infants was 2.6 (P = 0.03), and for PT compared with FT infants the risk ratio was 1.6 (P = 0.06). Vaccine efficacy for both groups was 100%. PCV was as immunogenic in LBW and PT as in NBW and FT infants. Fever and local events after PCV vaccination were similar when adjusted for clustering among multiple doses per child. When stratified for individual doses there was more redness and swelling for LBW infants and more swelling for PT infants after Dose 3. Isolated local and systemic reactions were more commonly seen with PCV than with MCV, a pattern similar to that in NBW and FT infants. Hospitalization rates were similar for PCV and MCV recipients.

CONCLUSION

These data support the use of PCV in LBW infants and PT infants.

Use of a Staphylococcus aureus conjugate vaccine in patients receiving hemodialysis

BACKGROUND

In patients with decreased resistance to infection, Staphylococcus aureus is a major cause of bacteremia and its complications. The capsular polysaccharides are essential for the pathogenesis of and immunity to S. aureus infection and are targets for vaccines.

METHODS

In a double-blind trial involving patients with end-stage renal disease who were receiving hemodialysis, we evaluated the safety, immunogenicity, and efficacy of a vaccine with S. aureus type 5 and 8 capsular polysaccharides conjugated to nontoxic recombinant Pseudomonas aeruginosa exotoxin A. Between April 1998 and August 1999, 1804 adult patients at 73 hemodialysis centers were randomly assigned to receive a single intramuscular injection of either vaccine or saline. IgG antibodies to S. aureus type 5 and 8 capsular polysaccharides were measured for up to two years, and episodes of S. aureus bacteremia were recorded. Efficacy was estimated by comparing the incidence of S. aureus bacteremia in the patients who received the vaccine with the incidence in the control patients.

RESULTS

Reactions to the vaccine were generally mild to moderate, and most resolved within two days. The capsular polysaccharides elicited an antibody response of at least 80 microg per milliliter (the estimated minimal level conferring protection) in 80 percent of patients for type 5 and in 75 percent of patients for type 8. The efficacy during weeks 3 to 54 was only 26 percent (P=0.23). However, between weeks 3 and 40 after vaccination, S. aureus bacteremia developed in 11 of 892 patients in the vaccine group who could be evaluated for bacteremia, as compared with 26 of 906 patients in the control group (estimate of efficacy, 57 percent; 95 percent confidence interval, 10 to 81 percent; nominal P=0.02).

CONCLUSIONS

In patients receiving hemodialysis, a conjugate vaccine can confer partial immunity against S. aureus bacteremia for approximately 40 weeks, after which protection wanes as antibody levels decrease.

Incidence and hospitalization rates of varicella and herpes zoster before varicella vaccine introduction: a baseline assessment of the shifting epidemiology of varicella disease

BACKGROUND

A 15-year postmarketing evaluation of the impact of varicella vaccine on the age distribution of varicella disease is being conducted at Kaiser Permanente Medical Care Program, Northern California (KPMCP). We report on a baseline assessment of the age-specific incidence and hospitalization rates of varicella and herpes zoster that was conducted before vaccine introduction.

METHODS

To assess the annual incidence of varicella, a telephone survey was conducted in a random sample of approximately 8,000 youths 5 to 19 years of age. The annual incidence of hospitalizations for varicella and herpes zoster in 1994 was assessed with the use of the computerized database at KPMCP.

RESULTS

Varicella annual incidence was 10.3% in 5- to 9-year-olds, 1.9% in 10- to 14-year-olds and 1.2% in the 15- to 19-year age groups, respectively. Hospitalization rates among the entire KPMCP membership were 2.6 and 2.1 per 100,000 person years for varicella and zoster, respectively. Varicella incidence in the 15- to 19-year age group was higher among African-Americans than among Caucasians.

CONCLUSIONS

Varicella rates were similar in the 5- to 9- and 10- to 14-year age groups to rates from other published studies conducted in 1972 to 1978, 1980 to 1988 and 1990 to 1992; however, the rate in 15- to 19-year-olds was 2 to 4 times higher than published rates in the same age category.

Population-based study of rotavirus vaccination and intussusception

BACKGROUND

During the first year that the rhesus rotavirus tetravalent vaccine (RRV-TV) was licensed, the Vaccine Adverse Event Reporting System received several reports of intussusception after vaccination. To evaluate the risk of intussusception, we conducted a retrospective cohort study in ten managed care organizations.

METHODS

Cases of intussusception were identified by searching electronic databases for diagnoses of intussusception (ICD-9 Code 560.0) in infants 1 to 11 months of age and confirmed by medical chart review. Vaccination and enrollment data were obtained from administrative databases. Incidence rate ratios (RR) of intussusception were computed by dividing incidence rates in prespecified risk intervals after vaccination by the background rate of intussusception and adjusted for age by Poisson regression. Cox proportional hazard regression was used to evaluate risk by vaccine dose.

RESULTS

Of 463,277 children 56,253 had been vaccinated with a total of 91 371 doses of RRV-TV. The incidence rate of intussusception was 25/100,000 person years among unexposed infants and 340/100,000 person years 3 to 7 days postvaccination. In the interval 3 to 7 days after vaccination, the age-adjusted RR was 16.0 (95% confidence interval, 5.5 to 46.7) for all doses combined and 30.4 (95% confidence interval, 8.8 to 104.9) after the first dose. RRs for the 8- to 14- and 15- to 21-day risk intervals were >1.0, but the confidence intervals substantially overlapped 1.0. The attributable risk was one case of intussusception per 11 073 children vaccinated.

CONCLUSIONS

RRV-TV is associated with an increased risk of intussusception. The risk is greatest 3 to 7 days after the first vaccination dose.

Measles-mumps-rubella and other measles-containing vaccines do not increase the risk for inflammatory bowel disease: a case-control study from the Vaccine Safety Datalink project

CONTEXT

A link between measles virus-containing vaccines and inflammatory bowel disease (IBD) has been suggested by recent studies.

OBJECTIVE

To address whether receipt or timing of measles-containing vaccine (MCV) increases risk for IBD.

DESIGN

A case-control study.

SETTING

Four large health maintenance organizations (HMOs) that are part of the Centers for Disease Control and Prevention's Vaccine Safety Datalink project.

PATIENTS OR OTHER PARTICIPANTS

A total of 155 persons with codes from International Classification of Diseases, Ninth Revision specific for IBD, born between 1958 and 1989 and enrolled from birth to the onset of disease, were identified. Up to 5 controls were matched by sex, HMO, and birth year.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Risk for IBD, Crohn's disease, and ulcerative colitis.

RESULTS

Past vaccination was not associated with an increased risk for Crohn's disease (odds ratio [OR] for measles-mumps-rubella vaccine [MMR], 0.4; 95% confidence interval [CI], 0.08-2.0), ulcerative colitis (OR, 0.8; 95% CI, 0.18-3.56), or IBD (OR, 0.59; 95% CI, 0.21-1.68). Risk for IBD was not increased among children vaccinated who were younger than 12 months (OR for MMR, 0.61; 95% CI, 0.15-2.45) or aged 12 to 18 months (OR, 0.86; 95% CI, 0.28-2.59) relative to unvaccinated children. Children vaccinated with MMR who were older than 18 months were at significantly decreased risk for IBD (OR, 0.16; 95% CI, 0.04-0.68). Neither past vaccination nor age at vaccination with other MCV was associated with increased risk for Crohn's disease, ulcerative colitis, or IBD. Risk for Crohn's disease, ulcerative colitis, or IBD was not elevated in the time immediately following vaccination with either vaccine.

CONCLUSIONS

Vaccination with MMR or other MCV, or the timing of vaccination early in life, did not increase the risk for IBD.

Efficacy, safety and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Northern California Kaiser Permanente Vaccine Study Center Group

OBJECTIVE

To determine the efficacy, safety and immunogenicity of the heptavalent CRM197 pneumococcal conjugate vaccine against invasive disease caused by vaccine serotypes and to determine the effectiveness of this vaccine against clinical episodes of otitis media.

METHODS

The Wyeth Lederle Heptavalent CRM197 (PCV) was given to infants at 2, 4, 6 and 12 to 15 months of age in a double blind trial; 37,868 children were randomly assigned 1:1 to receive either the pneumococcal conjugate vaccine or meningococcus type C CRM197 conjugate. The primary study outcome was invasive disease caused by vaccine serotype. Other outcomes included overall impact on invasive disease regardless of serotype, effectiveness against clinical otitis media visits and episodes, impact against frequent and severe otitis media and ventilatory tube placement. In addition the serotype-specific efficacy against otitis media was estimated in an analysis of spontaneously draining ears.

RESULTS

In the interim analysis in August, 1998, 17 of the 17 cases of invasive disease caused by vaccine serotype in fully vaccinated children and 5 of 5 of partially vaccinated cases occurred in the control group for a vaccine efficacy of 100%. Blinded case ascertainment was continued until April, 1999. As of that time 40 fully vaccinated cases of invasive disease caused by vaccine serotype had been identified, all but 1 in controls for an efficacy of 97.4% (95% confidence interval, 82.7 to 99.9%), and 52 cases, all but 3 in controls in the intent-to-treat analysis for an efficacy of 93.9% (95% confidence interval, 79.6 to 98.5%). There was no evidence of any increase of disease caused by nonvaccine serotypes. Efficacy for otitis media against visits, episodes, frequent otitis and ventilatory tube placement was 8.9, 7.0, 9.3 and 20.1% with P < 0.04 for all. In the analysis of spontaneously draining ears, serotype-specific effectiveness was 66.7%.

CONCLUSION

This heptavalent pneumococcal conjugate appears to be highly effective in preventing invasive disease in young children and to have a significant impact on otitis media.

Influenza and the rates of hospitalization for respiratory disease among infants and young children

BACKGROUND

Young children may be at increased risk for serious complications from influenzavirus infection. However, in population-based studies it has been difficult to separate the effects of influenzavirus from those of respiratory syncytial virus. Respiratory syncytial virus often circulates with influenzaviruses and is the most frequent cause of hospitalization for lower respiratory tract infections in infants and young children. We studied the rates of hospitalization for acute respiratory-disease among infants and children during periods when the circulation of influenzaviruses predominated over the circulation of respiratory syncytial virus.

METHODS

For each season from October to May during the period from 1992 to 1997, we used local viral surveillance data to define periods in Washington State and northern California when the circulation of influenzaviruses predominated over that of respiratory syncytial virus. We calculated the rates of hospitalization for acute respiratory disease, excess rates attributable to influenzavirus, and incidence-rate ratios for all infants and children younger than 18 years of age who were enrolled in either the Kaiser Permanente Medical Care Program of Northern California or the Group Health Cooperative of Puget Sound.

RESULTS

The rates of hospitalization for acute respiratory disease among children who did not have conditions that put them at high risk for complications of influenza (e.g., asthma, cardiovascular diseases, or premature birth) and who were younger than two years of age were 231 per 100,000 person-months at Northern California Kaiser sites (from 1993 to 1997) and 193 per 100,000 person-months at Group Health Cooperative sites (from 1992 to 1997). These rates were approximately 12 times as high as the rates among children without high-risk conditions who were 5 to 17 years of age (19 per 100,000 person-months at Northern California Kaiser sites and 16 per 100,000 person-months at Group Health Cooperative sites) and approached the rates among children with chronic health conditions who were 5 to 17 years of age (386 per 100,000 person-months and 216 per 100,000 person-months, respectively).

CONCLUSIONS

Infants and young children without chronic or serious medical conditions are at increased risk for hospitalization during influenza seasons. Routine influenza vaccination should be considered in these children.

Postmarketing evaluation of the safety and effectiveness of varicella vaccine

BACKGROUND

The Oka strain of live attenuated varicella virus was licensed for use in healthy children in the United States in March, 1995. We report a postmarketing evaluation of the short term safety of this vaccine within Kaiser Permanente.

METHODS

After licensure varicella vaccination was introduced into the preventive care program of the Northern California Kaiser Permanente Medical Care Program. Potential adverse events after vaccination with varicella vaccine were identified from automated clinical databases of hospitalizations, emergency room visits and clinic visits. Deaths were identified from automated clinical databases at Kaiser as well as from the State death records for California. To evaluate safety, rates of diagnosis-specific events in the risk periods were compared with the rates of such diagnosis-specific events in two self control and one historical control period.

RESULTS

During the study period of April 1, 1995, to December 31, 1996, a total of 89753 adults and children received varicella vaccine. A total of 3200 relative risks were calculated, and of these 5 hospital diagnostic categories, 9 emergency visit diagnostic categories and 30 outpatient diagnostic categories demonstrated at least 1 relative risk with a P value of <0.05 in 1 or more age groups and in comparisons with 1 control period or more. The p value for these tests was not adjusted for multiple comparisons. Of these categories 14 demonstrated an increased risk either in more than 1 age group or against more than 1 comparison group. These categories included elective procedures, febrile seizure, febrile illness, well child, acute gastroenteritis, varicella, congenital anomaly, "rule out sepsis," trauma, viral syndrome, apnea, back pain, congenital valvular heart disease and vision evaluation for glasses. Of these the outcomes of elective procedure, congenital anomaly, congenital valvular heart disease, well child and vision evaluation for glasses were judged not to have a biologically plausible association with vaccination. A second diagnostic grouping included febrile illness, viral illness, febrile seizure and "rule out sepsis." In an analysis of these events which adjusted for the concomitant administration of M-M-R(II) vaccine, none of the associations was statistically associated with receipt of varicella vaccine. The diagnostic category of "rule out sepsis" still had a relative risk of 1.95 with P = 0.02. None of the children in the "rule out sepsis" category had positive bacteriologic cultures from any other normally sterile site. Because of the large number of gastroenteritis cases, we reviewed a random sample of 100 exposed and 100 unexposed cases. From this review no consistent time association or clustering of any of these events was seen in the exposed follow-up time interval. Only gastroenteritis and negative evaluations for sepsis were thought to be possibly associated with receipt of varicella vaccine. Although there was a statistically significant increased risk over the entire 30 day-period, there was no clustering of these events within the 30-day window.

CONCLUSION

In this study population of 89753 children and adults, the varicella vaccine (Oka strain, Merck) appeared to have a favorable safety profile. In addition rates of varicella-like rash and of breakthrough cases were both low and consistent with the rates observed in prelicensure studies.

Comparative safety of two recombinant hepatitis B vaccines in children: data from the Vaccine Adverse Event Reporting System (VAERS) and Vaccine Safety Datalink (VSD)

BACKGROUND

Preliminary review of data from the Vaccine Adverse Event Reporting System (VAERS), 1991-1994, revealed that more serious adverse events were reported in children who received a specific brand of recombinant hepatitis B (HepB) vaccine.

OBJECTIVE

To compare the post-marketing safety experience of the two recombinant HepB vaccines licensed for use in infants and children in the United States.

DESIGN

Review of a case series derived from passive surveillance data in the national VAERS. A retrospective cohort study using data from one health maintenance organization participating in Vaccine Safety Datalink (VSD), a computerized record linkage system. POPULATIONS STUDIED: U.S. children, ages birth-10 years for whom adverse events after HepB vaccine were reported to VAERS, 1991-1994. Children, ages birth-6 years, who received HepB vaccine at Kaiser Permanente Medical Care Program, Northern California, 1991-1994.

MAIN OUTCOME MEASURES

VAERS reporting rates for each vaccine by manufacturer were calculated from the numbers of reported events occurring within 30 days of HepB vaccination and the number of doses distributed by the manufacturers. VSD event rates for each vaccine were calculated from the numbers of hospitalization or emergency room visits within 30 days of HepB vaccination and the number of vaccine doses administered to the cohort.

RESULTS

In VAERS, higher rates of serious events (i.e., life threatening or resulting in hospitalization or permanent disability) were reported in children who received Vaccine A vs. Vaccine B (relative risk [RR]: 3.13-8.18, P < 0.01), particularly by those vaccinated in the private (RR: 7.62-28.58, P < 0.01), but not public sector (RR: 2.12, P = 0.19). Similar types of events were reported in recipients of both vaccines. In contrast, analysis of VSD data showed no significant difference in rates of hospitalization or ER visits in children who received either HepB vaccine (RR: 0.96-1.25, P > 0.05).

CONCLUSIONS

Our investigation reveals that it is unlikely there is a true difference between rates of serious events temporally associated with the two HepB vaccines in children. This study demonstrates the dual roles played by VAERS and VSD in providing a more complete picture of the post-marketing safety profile of childhood vaccines, and underscores the importance of using other analytic studies to evaluate findings from passive surveillance systems of adverse events.

MMR2 immunization at 4 to 5 years and 10 to 12 years of age: a comparison of adverse clinical events after immunization in the Vaccine Safety Datalink project. The Vaccine Safety Datalink Team

BACKGROUND

The Advisory Committee on Immunization Practices recommends a second dose of measles, mumps, and rubella vaccine (MMR2) at age 4 to 5 years of age, whereas the American Academy of Pediatrics suggests MMR2 immunization at age 11 to 12 years of age. Because there is little information on whether the rate of adverse reactions to MMR2 immunization varies among these two age groups, we took advantage of differing immunization policies at two large HMOs to compare the frequency of clinical events after, and possibly related to, MMR2 immunization.

METHODS

Information was collected on clinical events plausibly associated to MMR immunization (seizures, pyrexia, malaise/fatigue, nervous/musculoskeletal symptoms, rash, edema, induration/ecchymoses, lymphadenopathy, thrombocytopenia, aseptic meningitis, and joint pain) in two cohorts. At three facilities at Northern California Kaiser (Oakland, CA), 8514 children received MMR2 immunization at age 4 to 6 years of age; at Group Health Cooperative (Seattle, WA) 18 036 children received MMR2 immunization at age 10 to 12 years of age. To account for age-related differences in health care use, within each HMO, clinical events in a 30-day period after immunization were compared with a 30-day period before vaccination.

RESULTS

Children 10 to 12 years of age were 50% more likely to have a clinical event after MMR2 immunization than in the period before immunization (odds ratio, 1.45; 95% confidence interval: 1.00,2.10). Children 4 to 6 years of age were less likely to have a visit for an event after immunization compared with the period before immunization (odds ratio, 0.64; 95% confidence interval: 0.40,1.01).

CONCLUSIONS

These results suggest that the risk for clinical events after MMR2 immunizations is greater in the 10- to 12-year age group.

Risk of chronic arthropathy among women after rubella vaccination. Vaccine Safety Datalink Team

CONTEXT

A review by the Institute of Medicine found a possible relationship between rubella vaccination and chronic arthritis among women.

OBJECTIVE

To evaluate the risk of persistent joint and neurologic symptoms in rubella seronegative women subsequently vaccinated with RA 27/3 rubella vaccine.

DESIGN

Retrospective cohort study based on computerized laboratory data and medical record review. Records were reviewed for symptoms occurring within 2 years before and after the date of serological testing and to identify vaccinees. Possible cases were evaluated by a rheumatologist blinded to serological findings and vaccination status.

SETTING

Large health maintenance organization in northern California.

PATIENTS

Women aged 15 to 59 years serotested for rubella during 1990 with continuous health plan membership for 2 years before and after the date of their serological test. Seronegative women immunized within 1 year of serotesting (n=971) were defined as exposed. Primary comparison groups included all unvaccinated, seronegative women (n=924) and randomly selected seropositive, unvaccinated women (n=2421) matched to exposed subjects on serological test date and age (+/-3 years).

MAIN OUTCOME MEASURES

Prevalence and incidence of chronic joint and neurologic symptoms during 1-year follow-up period stratified by age and serological findings, immunization, and postpartum status.

RESULTS

No significantly increased risk was associated with receipt of rubella vaccine for any outcome except for prevalence of carpal tunnel syndrome in vaccinated women at least 30 years old compared with seropositive, unvaccinated women (2.9% vs 1.4%; P=.03). A total of 34 women had onset of conditions within the 1-year follow-up period; 9 of these were in the group of seronegative, immunized women, of whom 6 had onset of symptoms within 6 weeks of vaccination. Among these 6 women, symptoms included transient arthritis or arthralgias (<6 weeks duration) in 4 women, arthralgia of indeterminate chronicity in 1 woman, and carpal tunnel syndrome in 1 woman. Postpartum women across all groups were less likely to be seen for nontraumatic arthropathies than nonpostpartum women (4.5% vs 7.2%, P=.08 in vaccinated women; 4.8% vs 8.1%, P=.09 in seronegative controls; and 4.8% vs 10.0%, P=.01 in seropositive controls).

CONCLUSIONS

In this large retrospective cohort analysis there was no evidence of any increased risk of new onset chronic arthropathies or neurologic conditions in women receiving the RA 27/3 rubella vaccine. These data support the continued vaccination of rubella-susceptible women to reduce the risk of congenital rubella syndrome.

Risk of hospitalization because of aseptic meningitis after measles-mumps-rubella vaccination in one- to two-year-old children: an analysis of the Vaccine Safety Datalink (VSD) Project

OBJECTIVE

To assess the level of increased risk, if any, of hospitalizations for aseptic meningitis after Jeryl-Lynn mumps strain measles-mumps-rubella (MMR) vaccine in the Vaccine Safety Datalink population.

STUDY DESIGN

A possible increased risk of aseptic meningitis 8 to 14 days after receipt of MMR was observed in a preliminary screening analysis of automated data from the Vaccine Safety Datalink (VSD) project Year 2 analysis. To further evaluate this association a retrospective 10-year matched case-control study was undertaken in the four health maintenance organizations (HMOs) in the VSD project. Cases ascertained from a broad scan of the automated data were validated against a standard case definition. Two controls matched on age, sex, HMO and HMO membership were assigned per case.

RESULTS

The VSD project involves the cooperative collection of automated vaccination and medical outcome data from four large HMOs that currently have 500,000 children younger than 7 years of age under surveillance. Review of automated screening results from the first 2 years of data revealed a possible increased risk of aseptic meningitis 0 to 14 days after MMR with a relative risk of 3.61 (95% confidence interval, 1.0 to 13.1) although the total number of cases was small. Although the automated data had suggested a possible association of aseptic meningitis with MMR containing the Jeryl-Lynn strain of mumps, review of validated hospitalized cases during the observation period did not reveal evidence of an increased risk of aseptic meningitis after MMR containing the Jeryl-Lynn strain of mumps (odds ratio < 1.0 for all analyses).

CONCLUSION

Although it is recognized that hospitalized cases represent a minority of the total cases of aseptic meningitis, it is reassuring that in this evaluation no increased risk of aseptic meningitis after MMR vaccine was found.

Immunization tracking systems: experience of the CDC Vaccine Safety Datalink sites

Recognizing the potential of large databases within HMOs for the evaluation of vaccine safety, the Centers for Disease Control and Prevention (CDC) funded the Vaccine Safety Datalink project, linking outcome and vaccine exposure information at Group Health Cooperative of Puget Sound, Kaiser Permanente Northwest, Kaiser Permanente Medical Care Program Northern California, and Southern California Kaiser Permanente. Integral to the Vaccine Safety Datalink Project was the development of Immunization Tracking Systems at each site; this report describes the effort required to establish these tracking systems. Essential requirements are the methods used to insure data quality and to educate system users. Tracking systems can be a valuable means for assessing vaccine coverage, evaluating barriers to complete immunization, and studying the effectiveness of interventions design to improve immunization coverage. Finally, we report on recent efforts to link HMO Immunization Tracking Systems with developing regional tracking systems.

A pediatric screening examination for psychosocial problems

In an effort to avert the cumulative effects of unresolved emotional problems on children's social and school adjustment, a psychosocial phase was added to a pediatric multiphasic examination. Based upon a cumulative stress concept, the screening procedures included child behavior and family stress questionnaires for parents, and abbreviated standard psychological tests for children, administered by specially trained aides. Computerized results were reported to the child's pediatrician. Follow-up by mental health counselors attached to the pediatric clinic was provided for patients identified as being at high risk of serious psychosocial problems. Evidence of validity of the screen, factors affecting the scores, and effectiveness of clinical follow-up of high-risk patients are discussed. Valid semicomputerized screening of school-age children for serious psychosocial problems can be carried out routinely and at relatively low cost by paraprofessional personnel in a pediatric setting. Impediments to effective use of the screening results on the part of both health care provider and patient are discussed.