Revaccination and Adverse Event Recurrence in Patients with Adverse Events following Immunization.

OBJECTIVES: To estimate the risk of recurrence of adverse events following immunization (AEFIs) upon revaccination and to determine among patients with suspected vaccine allergy whether allergy skin test positivity was associated with AEFI recurrence. STUDY DESIGN: This prospective observational study included patients assessed in the Canadian Special Immunization Clinic Network from 2013 to 2019 with AEFIs who required revaccination with the vaccine temporally associated with their AEFI. Participants underwent standardized assessment and data collection. Special Immunization Clinic physicians used guidelines to inform their recommendations. Participants were followed up after revaccination to capture AEFI recurrences. Data were transferred to a central database for descriptive analysis. RESULTS: Overall, 588 participants were assessed for 627 AEFIs; 570 (91%) AEFIs occurred in children <18 years of age. AEFIs included immediate hypersensitivity (130/627; 21%), large local reactions (110/627; 18%), nonurticarial rash (51/627; 8%), seizures (26/627; 4%), and thrombocytopenia (11/627; 2%). Revaccination was recommended to 513 of 588 (87%) participants. Among participants recommended and due for revaccination during the study period, 63% (299/477) were revaccinated. AEFI recurrence was 10% (31/299) overall, 31% (15/49) for large local reactions, and 7% (5/66) for immediate hypersensitivity. No recurrence was serious. Among 92 participants with suspected vaccine allergy who underwent skin testing and were revaccinated, the negative predictive value of skin testing for AEFI recurrence was 96% (95% CI 92.5%-99.5%). CONCLUSIONS: Most individuals with AEFIs were safely revaccinated. Among those with suspected vaccine allergy, skin testing may help determine the safety of revaccination.

Waning Vaccine Immunity and Vaccination Responses in Children Treated for Acute Lymphoblastic Leukemia: A Canadian Immunization Research Network Study.

BACKGROUND: There is no uniform guideline for postchemotherapy vaccination of children with acute lymphoblastic leukemia (ALL). We evaluated waning immunity to 14 pneumococcal serotypes, pertussis toxin (PT), tetanus toxoid (TT) and varicella, and immunogenicity of postchemotherapy diphtheria, tetanus, pertussis, hepatitis B, polio, and Haemophilus influenzae type b (DTaP-IPV-Hib) and pneumococcal vaccination among previously vaccinated children treated for ALL. METHODS: This was a multicenter trial of children with ALL enrolled 4-12 months postchemotherapy completion. Exclusion criteria included: infant ALL, relapsed ALL, and stem cell transplant recipients. Immunocompetent children were recruited as controls. Postchemotherapy participants received DTaP-IPV-Hib and 13-valent pneumococcal conjugate vaccine (PCV13) concurrently, followed by 23-valent pneumococcal polysaccharide vaccine (PPV23) 2 months later. Serology was measured at baseline, 2 and 12 months postvaccination. Adverse events were captured via surveys. RESULTS: At enrollment, postchemotherapy participants (n = 74) were less likely than controls (n = 78) to be age-appropriately immunized with DTaP (41% vs 89%, P < .001) and PCV (59% vs 79%, P = .008). Geometric mean concentrations (GMCs) to TT, PT, PCV serotypes, and varicella were lower in postchemotherapy participants than controls after adjusting for previous vaccine doses (P < .001). Two months postvaccination, GMCs to TT, PT, and PCV serotypes increased from baseline (P < .001 for all antigens) and remained elevated at 12 months postvaccination. Antibody levels to PPV23 serotypes also increased postvaccination (P < .001). No serious adverse events were reported. CONCLUSIONS: Children treated for ALL had lower antibody levels than controls against pneumococcal serotypes, tetanus, pertussis, and varicella despite previous vaccination. Postchemotherapy vaccination with DTaP-IPV-Hib, PCV13, and PPV23 was immunogenic and well tolerated. Children with ALL would benefit from systematic revaccination postchemotherapy. CLINICAL TRIALS REGISTRATION: NCT02447718.

Children hospitalized with respiratory syncytial virus infection in Saskatchewan pediatric tertiary care centers, 2002-2005.

OBJECTIVE: To describe the epidemiology and severity of illness of children hospitalized with respiratory syncytial virus (RSV) infection, including those who received palivizumab prophylaxis, at Royal University Hospital (RUH), Saskatoon and Regina General Hospital (RGH) from July 2002 to June 2005. METHODS: Children hospitalized for ≥ 24 hours with laboratory-confirmed RSV infection were enrolled, and their health records were retrospectively reviewed for patient demographics and referral patterns, use of palivizumab prophylaxis, severity of infection (length of hospitalization, need for and duration of pediatric intensive care and mechanical ventilation) and outcome of infection. RESULTS: A total of 590 children (324 males) were hospitalized over the three years. The median chronological age at admission was 5.3 months, and median hospital stay was 4.0 days. Gestational age at birth was ≥ 36 weeks in 82.4% of patients. RSV disease severity was mild to moderate in 478 patients (81.0%) and severe in 110 (18.6%). Thirty-nine patients (6.6%) required pediatric intensive care unit admission, for a median of 5.0 days. Twenty-two of these patients (56%) were mechanically ventilated for a median of 6.0 days. Two children died, not attributed to RSV infection. Twenty-two patients had received palivizumab prophylaxis before hospital admission, with 18 completing at least 2 of the monthly doses. Most of these children (17/22) had mild to moderate illness. CONCLUSIONS: RSV causes significant morbidity in Saskatchewan, affecting predominantly term infants. The majority of illness is mild to moderate. Some patients who have received palivizumab may still develop significant RSV disease.

Revaccination outcomes among adolescents and adults with suspected hypersensitivity reactions following COVID-19 vaccination: A Canadian immunization research network study.

BACKGROUND: COVID-19 vaccination has been associated with anaphylaxis and hypersensitivity reactions. Infectious disease physicians and allergists in the Canadian Special Immunization Clinic (SIC) Network developed guidance for evaluating patients with adverse events following immunization (AEFI) including suspected hypersensitivity. This study evaluated management and adverse event recurrence following subsequent COVID-19 vaccinations. METHODS: Individuals aged 12 years and older enrolled at participating SICs before February 28, 2023 who were referred for suspected or diagnosed hypersensitivity reaction following COVID-19 vaccination, or for prevaccination assessment of suspected allergy to a COVID-19 vaccine component were included. De-identified clinical assessments and revaccination data, captured in a centralized database, were analyzed. The Brighton Collaboration case definition (BCCD) for anaphylaxis (2023 version) was applied. RESULTS: The analysis included 206 participants from 13 sites: 26 participants referred for pre-vaccination assessment and 180 participants referred for adverse events following COVID-19 vaccination (15/180 [8.3%] with BCCD confirmed anaphylaxis, 84 [46.7%] with immediate hypersensitivity symptoms not meeting BCCD, 33 [18.3%] with other diagnosed hypersensitivity reactions, and 48 [26.7%] participants with a final diagnosis of non-hypersensitivity AEFI). Among participants referred for AEFIs following COVID-19 vaccination, 166/180 (92.2%) were recommended for COVID-19 revaccination after risk assessment, of whom 158/166 (95.2%) were revaccinated (all with a COVID-19 mRNA vaccine). After revaccination, 1/15 (6.7%) participants with prior anaphylaxis, 1/77 (1.3%) with immediate hypersensitivity not meeting criteria for anaphylaxis and 1/24 (4.2%) with other physician diagnosed hypersensitivity developed recurrent AEFI symptoms that met the BCCD for anaphylaxis. All 26 participants referred pre-vaccination, including 9 (34.6%) with history of polyethylene glycol-asparaginase reactions, were vaccinated without occurrence of immediate hypersensitivity symptoms. CONCLUSIONS: Most individuals in this national cohort who experienced a hypersensitivity event following COVID-19 vaccination and were referred for specialist review were revaccinated without AEFI recurrence, suggesting that specialist evaluation can facilitate safe revaccination.

Influenza vaccination among household contacts of children with cystic fibrosis and healthy children.

BACKGROUND: It is recommended that household contacts of children with cystic fibrosis and household contacts of children <2 years of age receive annual influenza vaccinations. There is little information documenting whether this recommendation is being followed. METHODS: A 20-question survey was distributed to caregivers of children with cystic fibrosis and to caregivers of healthy children <17 years of age seen in a Saskatoon (Saskatchewan) tertiary care centre. Survey questions addressed the influenza vaccination status of the child and household contacts. Respondents were also asked to rate the influence of various factors on the decision to vaccinate, using a 5-point Likert scale. RESULTS: Reported vaccination rates were 21%, 25% and 7% among household contacts of children with cystic fibrosis, children <2 years of age and children ≥2 years of age, respectively. Advice from their physician, belief that they were too healthy, and inconvenient times and locations of vaccination centres were significant influences when compared among the three groups. Other main deterrents to vaccination were belief that the vaccine does not prevent influenza and belief that its side effects are greater than its benefits. CONCLUSION: By understanding motivators and barriers to vaccination among household contacts of children with cystic fibrosis, effective strategies may be implemented to improve vaccination coverage against influenza. Strong recommendations by clinicians and improved access to vaccination centres are essential components in improving influenza vaccination coverage.

HISTORIQUE: Il est recommandé d'administrer annuellement le vaccin contre l'influenza aux contacts familiaux d'enfants ayant la fibrose kystique et d'enfants de moins de deux ans. Peu d'information étaye le respect de cette recommandation. MÉTHODOLOGIE: Un sondage de 20 questions a été distribué aux personnes qui s'occupent d'enfants ayant la fibrose kystique et d'enfants en santé de moins de 17 ans vus dans un centre de soins tertiaires de Saskatoon, en Saskatchewan. Les questions du sondage portaient sur le statut de vaccination contre l'influenza de l'enfant et des contacts familiaux. Les répondants ont également été invités à classer l'influence de divers facteurs sur la décision de vacciner, selon l'échelle de cinq points de Likert. RÉSULTATS: Les taux de vaccination déclarés s'élevaient à 21 %, 25 % et 7 % chez les contacts familiaux d'enfants atteints de la fibrose kystique, les enfants de moins de deux ans et les enfants de deux ans et plus, respectivement. Les conseils du médecin, la conviction qu'ils étaient en trop bonne santé, de même que les heures d'ouverture et le lieu peu pratiques des centres de vaccination étaient des influences importantes au sein des trois groupes. Les autres principaux freins à la vaccination étaient la conviction que le vaccin ne prévient pas l'influenza et la conviction que ses effets secondaires sont plus importants que ses avantages. CONCLUSION: Si on comprend les sources de motivation et les obstacles à la vaccination des contacts familiaux d'enfants atteints de la fibrose kystique, on pourra peut-être adopter des stratégies efficaces pour améliorer la couverture vaccinale contre l'influenza. Des recom-mandations convaincues de la part des cliniciens et un meilleur accès aux centres de vaccination sont des éléments essentiels à une amélioration de la couverture vaccinale.

Factors associated with intention for revaccination among patients with adverse events following immunization.

OBJECTIVES: Individuals and healthcare providers may be uncertain about the safety of revaccination after an adverse event following immunization (AEFI). We identified factors associated with physician recommendation for revaccination and participant intention to be revaccinated among patients with adverse events following immunization (AEFIs) assessed in the Canadian Special Immunization Clinic (SIC) Network from 2013 to 2019. METHODS: This prospective observational study included patients assessed in the Canadian Special Immunization Clinic Network from 2013 to 2019 for an AEFI who required additional doses of the vaccine temporally associated with their AEFI. Participants underwent standardized assessment and data collection. Physician recommendations regarding revaccination and participant intent for revaccination were recorded. AEFI impact on daily activities and need for medical attention was captured as low, moderate, high impact and serious (e.g., requiring hospitalization). Multivariable logistic regression analysis identified factors associated with physician recommendation and participant intention for revaccination, controlling for province of assessment. RESULTS: Physician recommendation was significantly associated with the type of AEFI and AEFI impact. Compared to large local reaction, physician recommendation for revaccination was reduced for immediate hypersensitivity (aOR: 0.24 [95% CI: 0.08-0.76]) and new onset autoimmune disease (aOR: 0.16; 95% CI: 0.04-0.69). Compared to low impact AEFIs, physician recommendation was reduced for moderate (aOR: 0.22 [95% CI: 0.07-0.65]), high impact (aOR: 0.08 [95% CI: 0.02-0.30]), and serious AEFIs (aOR: 0.11 [95% CI: 0.03-0.37]). Participant intention for revaccination was significantly associated with AEFI impact, with reduced odds for high versus low impact AEFIs (aOR: 0.12 [95% CI: 0.04-0.42]). CONCLUSION: Physicians appear to use AEFI type and impact to guide recommendations while patients use primarily AEFI impact to form intentions for revaccination. The findings may help inform counselling for patients with AEFIs.

Physician vaccination practices in mild to moderate inborn errors of immunity and retrospective review of vaccine completeness in IEI: results from the Canadian Immunization Research Network.

BACKGROUND AND OBJECTIVES: Safety and effectiveness concerns may preclude physicians from recommending vaccination in mild/moderate inborn errors of immunity (IEI). This study describes attitudes and practices regarding vaccination among physicians who care for patients with mild/moderate B cell or mild/moderate combined immunodeficiencies (CID) and vaccination completeness among patients diagnosed with IEIs. METHODS: Canadian physicians caring for children with IEI were surveyed about attitudes and practices regarding vaccination in mild/moderate IEI. Following informed consent, immunization records of pediatric patients with IEI evaluated before 7 years of age were reviewed. Vaccine completeness was defined at age 2 years as 4 doses of diphtheria-tetanus-pertussis (DTaP), 3 doses pneumococcal conjugate (PCV), and 1 dose measles-mumps-rubella (MMR) vaccines. At 7 years 5 doses of DTP and 2 doses MMR were required. RESULTS: Forty-five physicians from 8 provinces completed the survey. Most recommended inactivated vaccines for B cell deficiency: (84% (38/45) and CID (73% (33/45). Fewer recommended live attenuated vaccines (B cell: 53% (24/45), CID 31% (14/45)). Of 96 patients with IEI recruited across 7 centers, vaccination completeness at age 2 was 25/43 (58%) for predominantly antibody, 3/13 (23%) for CID, 7/35 (20%) for CID with syndromic features, and 4/4 (100%) for innate/phagocyte defects. Completeness at age 7 was 15%, 17%, 5%, and 33%, respectively. CONCLUSION: Most physicians surveyed recommended inactivated vaccines in children with mild to moderate IEI. Vaccine completeness for all IEI was low, particularly at age 7. Further studies should address the reasons for low vaccine uptake among children with IEI and whether those with mild-moderate IEI, where vaccination is recommended, eventually receive all indicated vaccines.

Clinical Presentations and Outcomes of Children in Canada With Recurrent Invasive Pneumococcal Disease From the IMPACT Surveillance Network.

BACKGROUND: Invasive pneumococcal disease due to Streptococcus pneumoniae can cause mortality and severe morbidity due to sepsis, meningitis and pneumonia, particularly in young children and the elderly. Recurrent invasive pneumococcal disease is rare yet serious sequelae of invasive pneumococcal disease that is associated with the immunocompromised and leads to a high mortality rate. METHOD: This retrospective study reviewed recurrent invasive pneumococcal disease cases from the Canadian Immunization Monitoring Program, ACTive (IMPACT) between 1991 and 2019, an active network for surveillance of vaccine-preventable diseases and adverse events following immunization for children ages 0-16 years. Data were collected from 12 pediatric tertiary care hospitals across all 3 eras of public pneumococcal conjugate vaccine implementation in Canada. RESULTS: The survival rate within our cohort of 180 recurrent invasive pneumococcal disease cases was 98.3%. A decrease of 26.4% in recurrent invasive pneumococcal disease due to vaccine serotypes was observed with pneumococcal vaccine introduction. There was also a 69.0% increase in the rate of vaccination in children with preexisting medical conditions compared with their healthy peers. CONCLUSION: The decrease in recurrent invasive pneumococcal disease due to vaccine-covered serotypes has been offset by an increase of non-vaccine serotypes in this sample of Canadian children.

Invasive infections caused by haemophilus influenzae serotypes in twelve Canadian IMPACT centers, 1996-2001.

BACKGROUND: Haemophilus influenzae type b (Hib) immunization has changed the epidemiology of pediatric bacterial invasive disease. We describe the epidemiology of H. influenzae invasive infections in 12 Canadian pediatric tertiary care [Immunization Monitoring Program, ACTive (IMPACT)] centers during the era of universal immunization against this pathogen. METHODS: Children with positive cultures for H. influenzae serotypes a to f (Hia to Hif) and nontypable H. influenzae from sterile sites were identified from the laboratory records at 12 IMPACT centers from January 1, 1996 to December 31, 2001. Hospital records were retrospectively reviewed for demographic and clinical information. RESULTS: Of 166 H. influenzae cases, 58 (35%) were caused by Hib, 89 (54%) by non-b serotypes, and 19 (11%) were not serotyped. The non-b serotypes included: 25 Hia (28%), 4 Hid (4%), 2 Hie (2%), 11 Hif (12%), and 47 were nontypable isolates (53%). For patients with Hib and Hia infection, meningitis was the most common presentation, accounting for 40% and 52% respectively, whereas the most common presentation for nontypable serotypes was pneumonia, seen in 43% of cases. Epiglottitis was associated mainly with Hib. Aboriginal ethnicity was an important risk factor for Hia cases, accounting for 76% of patients with infections caused by this serotype. Mean duration of hospitalization, need for admission to a pediatric intensive care unit, and case fatality rates were similar for the cases because of Hib, Hia, Hif, and nontypable serotypes. CONCLUSIONS: In 1996-2001, two-thirds of H. influenzae invasive disease in the 12 IMPACT centers was caused by non-b serotypes, which were associated with significant morbidity and mortality.

Immunizing Patients With Adverse Events After Immunization and Potential Contraindications to Immunization: A Report From the Special Immunization Clinics Network.

BACKGROUND: For patients who have experienced adverse events following immunization (AEFI) or who have specific medical conditions, there is limited evidence regarding the best approach to immunization. The Special Immunization Clinics (SICs) Network was established to standardize patient management and assess outcomes after reimmunization. The study objective was to describe the first 2 years of the network's implementation. METHODS: Twelve SICs were established across Canada by infectious diseases specialists and allergists. Inclusion criteria were as follows: local reaction ≥ 10 cm, allergic symptoms < 24 hours postimmunization, neurologic symptoms and other AEFI or medical conditions of concern. Eligible patients underwent a standardized evaluation, causality assessment was performed, immunization recommendations were made by expert physicians and patients were followed up to capture AEFI. After individual consent, data were transferred to a central database for analysis. RESULTS: From June 2013 to May 2015, 151 patients were enrolled. Most were referred for prior AEFI (132/151, 87%): 42 (32%) for allergic-like reactions, 31 (23%) for injection-site reactions, 20 (15%) for neurologic symptoms and 39 (30%) for other systemic symptoms. Nineteen patients (13%) were seen for underlying conditions that complicated immunization. Reimmunization was recommended for 109 patients, 60 of whom (55%) were immunized and followed up. Eleven patients (18%) experienced recurrence of their AEFI; none were serious (eg, resulting in hospitalization, permanent disability or death). CONCLUSIONS: The most frequent reasons for referral to a SIC were allergic-like events and injection site reactions. Reimmunization was safe in most patients. Larger studies are needed to determine outcomes for specific types of AEFI.

Student perceptions of the care of children: impacts of pre-clerkship pediatric and primary care clinical teaching.

BACKGROUND: Pediatric clinical skills teaching sessions provide an early opportunity for students to be exposed to the medical care of children. This report describes second and third year medical students' perceptions of and attitudes towards working with children before and after the pediatric clinical skills teaching sessions, and the experiences of those students precepted by pediatricians only compared to those students working with a combination of pediatricians and family physicians. METHOD: A 13 question survey was voluntarily completed before and after teaching sessions. Written reflective assignments were qualitatively analyzed for key themes. Response rate averaged 68% with class sizes of 84 and 85 students. RESULTS: Students' perceptions of the care of children were generally very positive. Some differences were found based on gender, phase of study and prior clinical exposure to pediatric care. Pre and post responses were similar, regardless of preceptor specialty. Students with family physician preceptors identified the themes of prevention, health promotion and multidisciplinary care in their reflections. CONCLUSIONS: Students had already formed positive attitudes toward the medical care of children and intended to care for children in their future practice. Further research is needed into the effects of pre-clerkship experiences in the care of children on choice of medical specialty.

The effect of funded varicella immunization programs on varicella-related hospitalizations in IMPACT centers, Canada, 2000-2008.

BACKGROUND: The 12 Immunization Monitoring Program, Active (IMPACT) centers that represent 90% of pediatric tertiary care beds in Canada conducted active surveillance for varicella-related hospitalizations and complications from 1999 onward, after varicella vaccine was authorized. Publicly funded routine immunization programs at 12 or 15 months of age were introduced by 5 provinces and territories (prov/terr) in 2000 to 2002 (earlier programs, EP) and by 8 prov/terr in 2004 to 2007 (later programs, LP). OBJECTIVE: To determine whether the number of varicella-related hospitalized cases had declined by 2008 at 12 IMPACT centers after the sequential introduction of publicly funded varicella immunization programs in Canada. METHODS: Varicella-related hospitalizations from 2000 to 2008 in the prov/terr with EP were under surveillance by 3 IMPACT centers (Halifax, Edmonton, Calgary), whereas the prov/terr with LP were under surveillance by the remaining 9 centers. The age, gender, underlying health status, varicella complications, and length of stay in hospital and the pediatric intensive care unit were documented. Breakthrough cases were identified and their clinical characteristics described. RESULTS: Between 2000 and 2008, the number of varicella-related hospitalized cases in IMPACT centers declined relatively sooner in prov/terr with EP (by 2002 to 2003), as compared to those with LP (only by 2007 to 2008). In 2008, varicella-related hospitalized cases declined by 88% in the EP centers, and by 81% in the LP centers. In all IMPACT centers, the greatest decline occurred in the 1-4 years age group (90% decline), with smaller declines in both <1 year and 5-9 years age groups (78% and 76% decline, respectively). Breakthrough disease accounted for 39 (2%) cases, with the proportion due to breakthrough increasing from 0.9% in 2000 to 2001, to 2% in 2003 to 2004 and 9.5% in 2007 to 2008. The majority (72%) of breakthrough cases were in immunocompromised children. CONCLUSIONS: Publicly funded varicella vaccination programs have led to a significant decline in varicella-related hospitalizations in Canadian children, as a result of direct effects of the program beginning within 1 to 2 years after the start, as well as probable indirect protection of children outside the vaccinated cohort.

Emergence of sylvatic Echinococcus granulosus as a parasitic zoonosis of public health concern in an indigenous community in Canada.

Within a remote Canadian Indigenous community, at least 11* of people had antibodies against Echinococcus granulosus and E. granulosus eggs were detected in 6* of environmentally collected canine fecal samples. Dog ownership, hunting, and trapping were not risk factors for seropositivity, suggesting that people are most likely exposed to E. granulosus through indirect contact with dog feces in the environment. In this situation, human exposure could be most effectively curtailed by preventing consumption of cervid viscera by free-roaming dogs.

Antimicrobial susceptibility of invasive and lower respiratory tract isolates of Streptococcus pneumoniae, 1998 to 2007.

Previous surveys of antimicrobial resistance in Streptococcus pneumoniae have found differences depending on source of isolate (eg, higher resistance in lower respiratory tract [LRT] versus invasive isolate) and age (higher resistance in children versus adults). Susceptibility profiles in the Calgary Health Region (approximately 1.25 million population) over a 10-year period were studied. Prospective laboratory-based population surveillance for S pneumoniae disease has been conducted since 1998. Patient demographics and susceptibility testing were analyzed. In total, 2382 patient isolates were available for analysis from 1998 to 2007. Of these, 1170 isolates were invasive while 496 were LRT. Patient age distribution was: younger than five years, 14%; five to 17 years, 6%; 18 to 64 years, 56%; and 65 years or older, 24%. Mean patient age was 44.8 years and 60.0% were male. The overall incidence of nonsusceptibility was: penicillin, 8.2%; amoxicillin, 0.3%; cefuroxime, 6.2%; ceftriaxone, 1.7%; erythromycin, 8.8%; trimethoprim-sulfamethoxazole (TMP-SMX), 25.6%; clindamycin, 2.3%; and levofloxacin, 0.2%. Overall resistance rates were stable, except for increasing erythromycin resistance from 5.4% (1998) to a high of 14.2% (2004) (P=0.007). Isolates that were nonsusceptible to penicillin or TMP-SMX were more likely to be multidrug resistant (P<0.001) compared with penicillin- or TMP-SMX-susceptible isolates. Compared with invasive isolates, LRT isolates showed more resistance to penicillin, TMP-SMX, cefuroxime and erythromycin, and were more likely to be multidrug resistant. Isolates from children younger than five years of age are more likely to be multidrug resistant and resistant to erythromycin and cefotaxime. Ongoing surveillance of S pneumoniae isolates is important because resistance rates vary by source and patient age among health care regions.

Myeloid leukemia in Prader-Willi syndrome.

OBJECTIVE: To evaluate the frequency of cancers recorded by the Surveillance, Epidemiology, and End Results (SEER) Program in persons with Prader-Willi syndrome (PWS) METHODS: A survey was mailed in 1994 to 1852 registrants of the PWS Association (USA) inquiring about a diagnosis of any type of benign tumor or cancer (malignant tumor or leukemia). The risk of developing cancer was then estimated by comparing the observed number of cancers in the PWS population during 1975 to 1994 to the expected number in the general US population using data from the 1971-1994 SEER Cancer Statistics Review. RESULTS: Of the 1852 persons, 1160 (63%) responded, or 75% (1160/1552) of those who received the survey. The total number of observed cancer cases in the PWS study population was 8 versus 4.80 expected in the general US population (P =.1610). Three cases of myeloid leukemia were observed versus 0.075 leukemias expected (P =.0001). CONCLUSIONS: There appears to be an increased risk of myeloid leukemias, but not other cancers, among persons with PWS.