Hazel J Clothier

Active surveillance for adverse events following immunization

Comprehensive surveillance of adverse events following immunization (AEFI) is required to detect potential serious adverse events that may not be identified in prelicensure vaccine trials. Surveillance systems have traditionally been passive, relying upon spontaneous reporting, but increasingly active surveillance and supplemental strategies are being incorporated into vaccine safety programs. These include active screening for targeted conditions of interest (e.g., hospitalization), monitoring of new data sources and real-time methodologies to detect changes in vaccine safety data in these sources. The role of improved causality assessment in AEFI surveillance is discussed, with its important role in determining whether a temporal association may have occurred by chance alone. Strong local vaccine safety networks are required to support national immunization programs, with recent progress in developing a framework for low- and middle-income countries. Global collaboration is increasingly required to address challenges in active AEFI surveillance, particularly for rare serious adverse events.

Geographic representativeness for sentinel infuenza surveillance: implications for routine surveillance and pandemic preparedness

Objective: To review the guidelines for geographic representativeness applied to sentinel infuenza surveillance as proposed in the Framework for an Australian Infuenza Pandemic Plan (1999).

Consumer reporting of adverse events following immunization

Surveillance of adverse events following immunisation (AEFI) is an essential component of vaccine safety monitoring. The most commonly utilized passive surveillance systems rely predominantly on reporting by health care providers (HCP). We reviewed adverse event reports received in Victoria, Australia since surveillance commencement in July 2007, to June 2013 (6 years) to ascertain the contribution of consumer (vaccinee or their parent/guardian) reporting to vaccine safety monitoring and to inform future surveillance system development directions. Categorical data included were: reporter type; serious and non-serious AEFI category; and, vaccinee age group. Chi-square test and 2-sample test of proportions were used to compare categories; trend changes were assessed using linear regression. Consumer reporting increased over the 6 years, reaching 21% of reports received in 2013 (P <0.001), most commonly for children aged less than 7 years. Consumer reports were 5% more likely to describe serious AEFI than HCP (P = 0.018) and 10% more likely to result in specialist clinic attendance (P <0.001). Although online reporting increased to 32% of all report since its introduction in 2010, 85% of consumers continued to report by phone. Consumer reporting of AEFI is a valuable component of vaccine safety surveillance in addition to HCP reporting. Changes are required to AEFI reporting systems to implement efficient consumer AEFI reporting, but may be justified for their potential impact on signal detection sensitivity.

Human papillomavirus vaccine in boys: background rates of potential adverse events.

Objectives: To determine background rates of potential adverse events following immunisation (AEFI) before expansion of the quadrivalent human papillomavirus (4vHPV) vaccination program to adolescent boys.

Limited provision of diagnostic services to Victorians living with hepatitis C antibodies, 2001–2012: a multi-level modelling analysis

Objective: To determine what percentage of Victorians with a history of notified hepatitis C exposure received appropriate follow‐up diagnostic services between 2001 and 2012.

Evaluation of the World Health Organization Global Measles and Rubella Quality Assurance Program, 2001–2008

BACKGROUND During 2001-2008, the Victorian Infectious Diseases Reference Laboratory (VIDRL) prepared and provided a measles and rubella proficiency test panel for distribution to the World Health Organization (WHO) measles and rubella network laboratories as part of their annual laboratory accreditation assessment. METHODS Panel test results were forwarded to VIDRL, and results from 8 consecutive years were analyzed. We assessed the type of assays used and results achieved on the basis of the positive and negative interpretation of submitted results, by year and WHO region, for measles and rubella. RESULTS Over time, there has been a noticeable increase in laboratory and WHO regional participation. For all panels, the proportion of laboratories in all WHO regions using the WHO-validated Dade Behring assay for measles and rubella-specific IgM antibodies ranged from 35% to 100% and 59% to 100%, respectively. For all regions and years, the proportion of laboratories obtaining a pass score ranged from 87% to 100% for measles and 93% to 100% for rubella. CONCLUSIONS During 2001-2008, a large proportion of laboratories worldwide achieved and maintained a pass score for both measles and rubella. Measles and rubella proficiency testing is regarded as a major achievement for the WHO measles and rubella laboratory program.

Allergic adverse events following 2015 seasonal influenza vaccine, Victoria, Australia

Australia was alerted to a possible increase in allergy-related adverse events following immunisation (AEFI) with 2015 seasonal trivalent influenza vaccines (TIV) by the Victorian state vaccine safety service, SAEFVIC. We describe SAEFVIC’s initial investigation and upon conclusion of the 2015 influenza vaccination programme, to define the signal event and implications for vaccine programmes. Allergy-related AEFI were defined as anaphylaxis, angioedema, urticaria or generalised allergic reaction. Investigations compared 2015 TIV AEFI reports to previous years as proportions and reporting risk (RR) per 100,000, stratified by influenza vaccine brand. The initial investigation showed an increased proportion of allergy-related AEFI compared with 2014 (25% vs 12%), predominantly in adults, with insufficient clinical severity to alter the programme risk-benefit. While overall TIV AEFI RR in 2015 was similar to previous years (RR: 1.07, 95% confidence interval (CI): 0.88–1.29), we identified a near-doubling RR for allergy-related AEFI in 2015 (RR: 1.78, 95% CI: 1.14– 2.80) from 2011 to 2014 with no difference by vaccine brand or severity increase identified. This increase in generalised allergy-related AEFI, across all used vaccine brands, supports evidence of variable reactogenicity arising from influenza vaccine strain variations. This investigation underlines the importance of effective seasonal influenza vaccine pharmacovigilance.

Surveillance of adverse events following the introduction of 13-valent pneumococcal conjugate vaccine in infants, and comparison with adverse events following 7-valent pneumococcal conjugate vaccine, in Victoria, Australia

The 13-valent pneumococcal vaccine (PCV13) replaced the 7-valent vaccine (PCV7) on the Australian National Immunization Program (NIP) in 2011. Post-marketing surveillance of adverse events following immunization (AEFI) is crucial for detecting potential safety signals and maintaining confidence in the NIP. This study describes all AEFI reported to Surveillance of Adverse Events following Vaccination in the Community (SAEFVIC), Melbourne, Australia, following both the primary series of PCV13 (children <7 months) and the catch-up dose (12 months–35months) in its first year of inclusion on the NIP. AEFI reporting rates per 100,000 doses of vaccine administered were compared for the PCV13 primary series and PCV7 primary series in the previous year. SAEFVIC received 229 reports describing 406 AEFI following PCV13 vaccine in the 12 months post introduction. There was no difference in the total number of AEFI cases reported between the vaccines but 7 AEFI categories were reported at a significantly higher rate following PCV13 compared with PCV7. No difference in reporting rate was observed for serious AEFI (p = 0.25). Post-hoc analysis of a further 12 months of PCV13 data revealed that all 7 AEFI categories that were initially reported at a significantly higher rate following PCV13 compared to PCV7 in the first 12 months post introduction, were no longer significantly increased in the 13–24 month period. The initial high reporting rate for several common AEFI post PCV13 compared to PCV7 may be explained by heightened awareness of the new vaccine. There were no safety signals detected for rare or serious AEFI that would require further investigation at this time.

Potential immediate hypersensitivity reactions following immunization in preschool aged children in Victoria, Australia

ABSTRACT Immediate hypersensitivity reactions (IHR) are rare but potentially serious adverse events following immunization (AEFI). Surveillance of Adverse Events following Vaccination in the Community (SAEFVIC) is an enhanced passive surveillance system that collects, analyses and reports information about AEFI in Victoria, Australia. We describe the incidence, timing and type of potential IHR following vaccination in preschool children reported over an 8-year period. A total of 2110 AEFI were reported in 1620 children, of which 23.5% (496) were classified as potential IHR. Of these, 37.1% (184) were suspected to be IgE-mediated, (including anaphylaxis, angioedema and/or urticaria) and 83.5% (414) occurred within 15 minutes of vaccination. The incidence of potential IHR was 5.4 per 100,000 doses, with that of suspected IgE-mediated IHR being 2.0 per 100,000 doses. The incidence of anaphylaxis was extremely low (0.13 per 100,000 doses) and is consistent with other published studies. Potential IHR following immunization should be reported to appropriate local pharmacovigilance systems and patients reviewed by specialists able to evaluate, investigate and manage future vaccinations.