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Dive into the research topics where Bradley K. Ackerson is active.

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Featured researches published by Bradley K. Ackerson.


Journal of Internal Medicine | 2012

Surveillance of autoimmune conditions following routine use of quadrivalent human papillomavirus vaccine.

Chun Chao; Nicola P. Klein; Christine Velicer; Lina S. Sy; J.M. Slezak; Harpreet Takhar; Bradley K. Ackerson; T.C. Cheetham; John Hansen; Kamala Deosaransingh; Michael Emery; Kai-Li Liaw; Steven J. Jacobsen

Abstract.  Chao C, Klein NP, Velicer CM, Sy LS, Slezak JM, Takhar H, Ackerson B, Cheetham TC, Hansen J, Deosaransingh K, Emery M, Liaw K‐L, Jacobsen SJ (Kaiser Permanente Southern California, Pasadena, CA; Kaiser Permanente Vaccine Study Center, Kaiser Permanente Northern California, Oakland, CA; Merck Research Laboratories, Upper Gwynedd, PA; South Bay Medical Center, Kaiser Permanente Southern California, Los Angeles, CA; and Kaiser Permanente Southern California, Downey, CA, USA). Surveillance of autoimmune conditions following routine use of quadrivalent human papillomavirus vaccine. J Intern Med 2012; 271: 193–203.


Vaccine | 2009

Observational safety study of febrile convulsion following first dose MMRV vaccination in a managed care setting

Steven J. Jacobsen; Bradley K. Ackerson; Lina S. Sy; Trung N. Tran; Tonia L. Jones; Janis F. Yao; Fagen Xie; T. Craig Cheetham; Patricia Saddier

BACKGROUND A combined measles, mumps, rubella, varicella live vaccine (MMRV, Merck and Co., Inc., US) was recently licensed in the US. Pre-licensure clinical trial data showed a significant increase in fever in days 5-12 following MMRV vaccination as compared to the vaccines given separately (MMR+V). This post-licensure retrospective cohort study was undertaken to assess the incidence of febrile convulsion following MMRV. METHODS Children ages 12-60 months who received a first dose of MMRV in February 2006-June 2007 in a managed care organization were included in the study. Subjects were optimally matched on age, sex, and calendar date of vaccination to children who received MMR+V concomitantly in November 2003-January 2006, before MMRV licensure. Potential cases of febrile convulsion were identified through administrative data and adjudicated by expert panel, according to pre-specified criteria. RESULTS During the 30 days post-vaccination, there were 128 and 94 potential convulsion cases among the 31,298 children in the MMRV and MMR+V cohorts, respectively. After review of available medical charts and adjudication, there were 84 cases of confirmed febrile convulsion, 44 (1.41/1000) and 40 (1.28/1000) in the MMRV and MMR+V cohorts, respectively (RR=1.10, 95% CI=0.72, 1.69). In days 5-12 following vaccination, a pre-specified period of interest, the respective numbers were 22 (0.70/1000) and 10 (0.32/1000) (RR=2.20, 95% CI=1.04, 4.65). CONCLUSION These data suggest that the risk of febrile convulsion is increased in days 5-12 following vaccination with MMRV as compared to MMR+V given separately during the same visit, when post-vaccination fever and rash are also increased in clinical trials. While there was no evidence of an increase in the overall month following vaccination, the elevated risk during this time period should be communicated and needs to be balanced with the potential benefit of a combined vaccine.


JAMA Pediatrics | 2012

Safety of quadrivalent human papillomavirus vaccine administered routinely to females.

Nicola P. Klein; John Hansen; Chun Chao; Christine Velicer; Michael Emery; Jeff Slezak; Ned Lewis; Kamala Deosaransingh; Lina S. Sy; Bradley K. Ackerson; T. Craig Cheetham; Kai-Li Liaw; Harpreet Takhar; Steven J. Jacobsen

OBJECTIVE To assess the safety of the quadrivalent human papillomavirus vaccine (HPV4) in females following routine administration. DESIGN In a cohort of vaccinated females, we compared the risk of emergency department visits and hospitalizations during the interval soon after vaccination with risk during a comparison interval more remote from vaccination. SETTING Kaiser Permanente in California. PARTICIPANTS All females who received the HPV4 vaccine. MAIN EXPOSURE One or more doses of HPV4 between August 2006 and March 2008. MAIN OUTCOME MEASURES Outcomes were emergency department visits and hospitalizations, grouped into predefined diagnostic categories. Within diagnostic groups, we used odds ratios (ORs) to estimate whether each subject had any outcome in postvaccination risk intervals (days 1-60, days 1-14, and day 0), compared with a control interval distant in time from vaccination. RESULTS One hundred eighty-nine thousand six hundred twenty-nine females received at least 1 dose and 44 001 received 3 HPV4 doses. Fifty categories had significantly elevated ORs during at least 1 risk interval. Medical record review revealed that most diagnoses were present before vaccination or diagnostic workups were initiated at the vaccine visit. Only skin infections during days 1 to 14 (OR, 1.8; 95% CI, 1.3-2.4) and syncope on day of vaccination (OR, 6.0; 95% CI, 3.9-9.2) were noted by an independent Safety Review Committee as likely associations with HPV4. CONCLUSIONS The quadrivalent human papillomavirus vaccine was associated with same-day syncope and skin infections in the 2 weeks after vaccination. This study did not detect evidence of new safety concerns among females 9 to 26 years of age secondary to vaccination with HPV4.


American Journal of Public Health | 2013

Quadrivalent Human Papillomavirus Vaccine Uptake in Adolescent Boys and Maternal Utilization of Preventive Care and History of Sexually Transmitted Infections

Rulin C. Hechter; Chun Chao; Lina S. Sy; Bradley K. Ackerson; Jeff Slezak; Margo A. Sidell; Steven J. Jacobsen

OBJECTIVES We examined whether maternal utilization of preventive care and history of sexually transmitted infections (STIs) predicted quadrivalent human papillomavirus vaccine (HPV4) uptake among adolescent boys 1 year following the recommendation for permissive use of HPV4 for males. METHODS We linked maternal information with electronic health records of 254 489 boys aged 9 to 17 years who enrolled in Kaiser Permanente Southern California health plan from October 21, 2009, through December 21, 2010. We used multivariable Poisson regression with robust error variance to examine whether HPV4 initiation was associated with maternal uptake of influenza vaccine, Papanicolaou (Pap) screening, and history of STIs. RESULTS We identified a modest but statistically significant association between initiation of HPV4 series and maternal receipt of influenza vaccine (rate ratio [RR] = 1.16; 95% confidence interval [CI] = 1.07, 1.26) and Pap screening (RR = 1.13; 95% CI = 1.01, 1.26). Boys whose mothers had a history of genital warts were more likely to initiate HPV4 (RR = 1.47; 95% CI = 0.93, 2.34), although the association did not reach statistical significance (P = .1). CONCLUSIONS Maternal utilization of preventive care and history of genital warts may influence HPV4 uptake among adolescent boys. The important role of maternal health characteristics and health behaviors needs be considered in intervention efforts to increase vaccine uptake among boys.


Vaccine | 2013

Agreement between medical record and parent report for evaluation of childhood febrile seizures.

Bradley K. Ackerson; Lina S. Sy; Janis F. Yao; T. Craig Cheetham; Ana M. Espinosa-Rydman; Tonia L. Jones; Steven J. Jacobsen

BACKGROUND The monitoring of vaccine safety is critical to maintaining the public acceptance of vaccines required to ensure their continued success. Methods used to assess adverse events following immunization (AEFI) must accurately reflect their occurrence. Assessment of AEFI is often done via medical record review (MR) or via patient report (PR). However, these sources of data have not previously been compared for the analysis of AEFI. The objective of this study was to evaluate the concordance between MR and PR for young children identified as having had a febrile seizure (FS), an important AEFI, in an integrated health care system. The variables chosen for analysis were those recommended by the Brighton Collaboration Seizure Working Group for the evaluation of generalized seizure as an AEFI [1]. METHODS Parent report from phone interviews and mailed questionnaires was compared to abstracted medical records of 110 children with FS between ages 3 and 60 months. Concordance between PR and MR for characteristics and predisposing factors of FS was assessed by percent total agreement and kappa statistic. RESULTS Percent total agreement between PR and MR was between 43.6 and 100% for variables studied, with 62.5% of items having >70% agreement. However, kappa was poor to fair for all measures (-0.04 to 0.33). While some variables, such as history of seizures in a sibling or parent and several seizure characteristics, were reported more often by PR, other items, such as maximum fever and several concurrent conditions, were reported more often by MR. CONCLUSION These findings demonstrate the limitations of using MR or PR alone to assess febrile seizures in children. This analysis supports the practice of collecting data from both MR and PR to most accurately portray the spectrum of predisposing factors and seizure characteristics when evaluating FS in children whenever feasible.


Pediatrics | 2017

Safety of Quadrivalent Meningococcal Conjugate Vaccine in 11- to 21-Year-Olds

Hung-Fu Tseng; Lina S. Sy; Bradley K. Ackerson; Rulin C. Hechter; Sara Y. Tartof; Mendel Haag; J.M. Slezak; Yi Luo; Christine A. Fischetti; Harp S. Takhar; Yan Miao; Marianne Cunnington; Zendi Solano; Steven J. Jacobsen

BACKGROUND: Meningococcal conjugate vaccination is recommended in the United States. This study evaluates the safety of quadrivalent meningococcal conjugate vaccine in a cohort aged 11 to 21 years. METHODS: This cohort study with self-controlled case-series analysis was conducted at Kaiser Permanente Southern California. Individuals receiving MenACWY-CRM, a quadrivalent meningococcal conjugate vaccine, during September 30, 2011 to June 30, 2013, were included. Twenty-six prespecified events of interest (EOIs), including neurologic, rheumatologic, hematologic, endocrine, renal, pediatric, and pediatric infectious disease EOIs, were identified through electronic health records 1 year after vaccination. Of these, 16 were reviewed by case review committees. Specific risk and comparison windows after vaccination were predefined for each EOI. The relative incidence (RI) and 95% confidence intervals (CIs) were estimated through conditional Poisson regression models, adjusted for seasonality. RESULTS: This study included 48 899 vaccinated individuals. No cases were observed in the risk window for 14 of 26 EOIs. The RI for Bell’s palsy, a case review committee-reviewed EOI, was statistically significant (adjusted RI: 2.9, 95% CI: 1.1–7.5). Stratified analyses demonstrated an increased risk for Bell’s palsy in subjects receiving concomitant vaccines (RI = 5.0, 95% CI = 1.4–17.8), and no increased risk for those without concomitant vaccine (RI = 1.1, 95% CI = 0.2–5.5). CONCLUSIONS: We observed a temporal association between occurrence of Bell’s palsy and receipt of MenACWY-CRM concomitantly with other vaccines. The association needs further investigation as it could be due to chance, concomitant vaccination, or underlying medical history predisposing to Bell’s palsy.


Pediatric Infectious Disease Journal | 2017

Safety of Quadrivalent Meningococcal Conjugate Vaccine in Children 2–10 Years

Sara Y. Tartof; Lina S. Sy; Bradley K. Ackerson; Rulin C. Hechter; Mendel Haag; Jeffrey M. Slezak; Yi Luo; Christine A. Fischetti; Harp S. Takhar; Yan Miao; Zendi Solano; Steven J. Jacobsen; Hung-Fu Tseng

Background: Quadrivalent meningococcal conjugate vaccine is recommended for children, adolescents and adults at increased risk of meningococcal disease. In 2011, MenACWY-CRM (Menveo, GSK, Siena, Italy) was approved for children 2–10 years of age in the United States. Although no safety concerns arose from clinical trials, it remains important to monitor its safety in routine clinical settings. Methods: Kaiser Permanente Southern California members 2–10 years old who received MenACWY-CRM between September 2011 and September 2014 were included. Electronic health records were searched using a validated algorithm to identify 26 prespecified events of interests (EOIs) and serious medically attended events (SMAEs) from inpatient or emergency settings up to 1 year after MenACWY-CRM vaccination. SMAEs were categorized by International Classification of Diseases, 9th revision diagnostic categories. All events were reviewed to confirm the diagnosis and symptom onset date. The study was descriptive (NCT01452438); no statistical tests were performed. Results: Among 387 vaccinated children, 327 with ≥6 months membership before vaccination were analyzed. Among EOIs, 9 asthma cases and 1 myasthenia gravis case underwent chart review which confirmed 1 incident asthma case occurring 237 days after concomitant vaccination with MenACWY-CRM and typhoid vaccine. Thirty-one children experienced SMAEs, most commonly because of unrelated injury and poisoning. The remaining events occurred sporadically after vaccination and most were unlikely related to vaccination based on medical record review. Conclusions: One incident EOI of asthma late in the 1-year observation period and sporadic distribution of SMAEs were observed. These data do not suggest safety concerns associated with MenACWY-CRM vaccination in children 2–10 years old.


American Journal of Public Health | 2015

Quadrivalent Human Papillomavirus Vaccine Initiation in Boys Before and Since Routine Use: Southern California, 2009–2013

Rulin C. Hechter; Chun R. Chao; Margo A. Sidell; Lina S. Sy; Bradley K. Ackerson; Jeff Slezak; Nilesh J. Patel; Hung Fu Tseng; Steven J. Jacobsen

OBJECTIVES We examined the trends and correlates of quadrivalent human papillomavirus vaccine (HPV4) initiation in insured boys during the periods before and after routine use recommendation. METHODS We grouped data from electronic medical records of boys aged 9 to 17 years from the Kaiser Permanente Southern California prepaid health plan into 3 open cohorts: permissive use: 2009 to 2010; anal cancer indication added: 2010 to 2011; and routine use: 2011 to 2013. We estimated adjusted risk ratios (ARRs) between demographics and vaccination initiation using Poisson regression. RESULTS HPV4 initiation increased across cohorts--1.6%, 3.4%, and 18.5%--with the greatest increase among boys aged 11 to 12 years in cohort 3. Initiation was associated with receiving influenza vaccination in the previous year in all cohorts (cohort 3: ARR = 1.48; 95% confidence interval [CI] = 1.46, 1.51) and with non-White race/ethnicity following routine recommendation (cohort 3, non-Hispanic Black: ARR = 1.18; 95% CI = 1.08, 1.30; Hispanic: ARR = 1.23; 95% CI = 1.17, 1.29; Asian/Pacific Islanders: ARR = 1.16; 95% CI = 1.11, 1.20). CONCLUSIONS Routine use recommendation increased the uptake of HPV4 in boys. System-level interventions to encourage providers to routinely recommend HPV4 vaccination may help increase HPV4 uptake in boys.


Human Vaccines & Immunotherapeutics | 2018

Postlicensure safety surveillance of congenital anomaly and miscarriage among pregnancies exposed to quadrivalent human papillomavirus vaccine

Lina S. Sy; Kristin Meyer; Nicola P. Klein; Chun Chao; Christine Velicer; T. Craig Cheetham; Bradley K. Ackerson; Jeff M. Slezak; Harpreet Takhar; John Hansen; Kamala Deosaransingh; Kai-Li Liaw; Steven J. Jacobsen

ABSTRACT Limited safety data are available on inadvertent exposure to quadrivalent human papillomavirus vaccine (4vHPV) during pregnancy. We conducted a descriptive observational postlicensure safety surveillance study in Kaiser Permanente Southern California and Northern California to assess congenital anomaly and miscarriage among pregnancies exposed to 4vHPV. Using electronic medical records, we identified women who received a dose of 4vHPV between August 2006 and March 2008 within 30 days preconception or any time during a possible pregnancy. A broad algorithm was developed using diagnostic and procedure codes and laboratory tests to identify pregnancy, congenital anomalies, and miscarriages. Medical records of all potential congenital anomaly cases and a random sample of 100 potential miscarriage cases were reviewed to confirm pregnancy exposure and diagnosis. Results were reviewed by an independent Safety Review Committee (SRC). Among the population of 189,629 females who received at least one dose of 4vHPV during the study period, 2,678 females were identified as possibly having a 4vHPV-exposed pregnancy. Among 170 potential congenital anomalies identified, 44 (26%) were found to be both 4vHPV-exposed and confirmed congenital anomaly cases. Among the 633 potential miscarriages identified, the records of a random sample of 100 cases were reviewed, and 9 cases (9%) were confirmed as 4vHPV-exposed miscarriages. The SRC noted no safety signal for congenital anomaly or miscarriage associated with 4vHPV exposure during pregnancy. The rate of major congenital anomaly (3.6%) was in the range of background estimates from the literature. There was no apparent pattern of timing of 4vHPV exposure among 4vHPV-exposed miscarriages.


Vaccine | 2012

An unmasking phenomenon in an observational post-licensure safety study of adolescent girls and young women.

Steven J. Jacobsen; Lina S. Sy; Bradley K. Ackerson; Chun R. Chao; Jeff M. Slezak; T. Craig Cheetham; Harpreet Takhar; Christine Velicer; John Hansen; Nicola P. Klein

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