Active surveillance of 2017 seasonal influenza vaccine safety: an observational cohort study of individuals aged 6 months and older in Australia

Factors influencing adverse events following COVID-19 vaccination

Various novel platform technologies have been used for the development of COVID-19 vaccines. In this nested cohort study among healthcare workers in Australia and Brazil who received three different COVID-19-specific vaccines, we (a) evaluated the incidence of adverse events following immunization (AEFI); (b) compared AEFI by vaccine type, dose and country; (c) identified factors influencing the incidence of AEFI; and (d) assessed the association between reactogenicity and vaccine anti-spike IgG antibody responses. Of 1302 participants who received homologous 2-dose regimens of ChAdOx1-S (Oxford-AstraZeneca), BNT162b2 (Pfizer-BioNTech) or CoronaVac (Sinovac), 1219 (94%) completed vaccine reaction questionnaires. Following the first vaccine dose, the incidence of any systemic reaction was higher in ChAdOx1-S recipients (374/806, 46%) compared with BNT162b2 (55/151, 36%; p = 0.02) or CoronaVac (26/262, 10%; p < 0.001) recipients. After the second vaccine dose, the incidence of any systemic reaction was higher in BNT162b2 recipients (66/151, 44%) compared with ChAdOx1-S (164/806, 20%; p < 0.001) or CoronaVac (23/262, 9%; p < 0.001) recipients. AEFI risk was higher in younger participants, females, participants in Australia, and varied by vaccine type and dose. Prior COVID-19 did not impact the risk of AEFI. Participants in Australia compared with Brazil reported a higher incidence of any local reaction (170/231, 74% vs 222/726, 31%, p < 0.001) and any systemic reaction (171/231, 74% vs 328/726, 45%, p < 0.001), regardless of vaccine type. Following a primary course of ChAdOx1-S or CoronaVac vaccination, participants who did not report AEFI seroconverted at a similar rate to those who reported local or systemic reactions. In conclusion, we found that the incidence of AEFI was influenced by participant age and COVID-19 vaccine type, and differed between participants in Australia and Brazil.

Reduction of adverse reactions and correlation between post-vaccination fever and specific antibody response across successive SARS-CoV-2 mRNA vaccinations

Background

SARS-CoV-2 mRNA vaccination, recognized for high immunogenicity, frequently induces adverse reactions, especially fever. We previously reported a correlation between post-vaccination fever and specific antibody responses to the primary series and first booster. We herein report changes in adverse reactions and the correlation between post-vaccination fever and antibody responses across successive vaccinations, from monovalent to bivalent mRNA vaccines.

Methods

This cohort study was conducted at a Japanese hospital to investigate adverse reactions to the monovalent primary, first booster, and BA.4/5 bivalent BNT162b2 vaccinations. Local and systemic reactions were reported through a self-reporting diary after each dose. The spike-specific IgG titers were measured following each vaccination.

Results

Across 727 vaccinations in the vaccine series, the bivalent booster induced fewer adverse reactions than earlier doses. Fever ≥ 38.0 °C was significantly less frequent in the bivalent booster (12.3 %) compared to the primary series and monovalent booster (22.0 %, 26.2 %, p < 0.001). Reaction severity was also reduced in the bivalent booster. In the analysis of 70 participants with complete data for all doses, post-vaccination fever ≥ 38.0 °C exhibited the highest relative risk (RR) among all solicited reactions throughout the vaccine series (RR: 5.24 [95 % CI: 2.40-11.42] for monovalent and 6.24 [95 % CI: 2.14-18.15] for bivalent). The frequency of fever ≥ 38.0 °C after all doses was 8.6 % (6/70), with no fever ≥ 39.0 °C across all vaccinations. A high-grade post-vaccination fever was correlated with higher IgG titers, with multivariate analyses confirming this correlation as independent for each dose and unaffected by previous post-vaccination fever.

Conclusions

The bivalent mRNA vaccine booster showed fewer and milder adverse reactions than the monovalent doses. Although vaccinees with a history of post-vaccination fever were more likely to experience fever after a subsequent dose, such recurrences were infrequent. A correlation between post-vaccination fever and increased IgG titers was identified for each vaccination, irrespective of post-vaccination fever history.

A Web-Based Tool to Report Adverse Drug Reactions by Community Pharmacists in Australia: Usability Testing Study

BACKGROUND

Adverse drug reactions (ADRs) are unintended and harmful events associated with medication use. Despite their significance in postmarketing surveillance, quality improvement, and drug safety research, ADRs are vastly underreported. Enhanced digital-based communication of ADR information to regulators and among care providers could significantly improve patient safety.

OBJECTIVE

This paper presents a usability evaluation of the commercially available GuildCare Adverse Event Recording system, a web-based ADR reporting system widely used by community pharmacists (CPs) in Australia.

METHODS

We developed a structured interview protocol encompassing remote observation, think-aloud moderating techniques, and retrospective questioning to gauge the overall user experience, complemented by the System Usability Scale (SUS) assessment. Thematic analysis was used to analyze field notes from the interviews.

RESULTS

A total of 7 CPs participated in the study, who perceived the system to have above-average usability (SUS score of 68.57). Nonetheless, the structured approach to usability testing unveiled specific functional and user interpretation issues, such as unnecessary information, lack of system clarity, and redundant data fields-critical insights not captured by the SUS results. Design elements like drop-down menus, free-text entry, checkboxes, and prefilled or auto-populated data fields were perceived as useful for enhancing system navigation and facilitating ADR reporting.

CONCLUSIONS

The user-centric design of technology solutions, like the one discussed herein, is crucial to meeting CPs' information needs and ensuring effective ADR reporting. Developers should adopt a structured approach to usability testing during the developmental phase to address identified issues comprehensively. Such a methodological approach may promote the adoption of ADR reporting systems by CPs and ultimately enhance patient safety.

Linking Activity Theory Within User-Centered Design: Novel Framework to Inform Design and Evaluation of Adverse Drug Reaction Reporting Systems in Pharmacy

BACKGROUND

Adverse drug reactions (ADRs) may cause serious injuries including death. Timely reporting of ADRs may play a significant role in patient safety; however, underreporting exists. Enhancing the electronic communication of ADR information to regulators and between health care providers has the potential to reduce recurrent ADRs and improve patient safety.

OBJECTIVE

The main objectives were to explore the low rate of ADR reporting by community pharmacists (CPs) in Australia, evaluate the usability of an existing reporting system, and how this knowledge may influence the design of subsequent electronic ADR reporting systems.

METHODS

The study was carried out in 2 stages. Stage 1 involved qualitative semistructured interviews to identify CPs' perceived barriers and facilitators to ADR reporting. Data were analyzed by thematic analysis, and identified themes were subsequently aligned to the task-technology fit (TTF) framework. The second stage involved a usability evaluation of a commercial web-based ADR reporting system. A structured interview protocol that combined virtual observation, think-aloud moderating techniques, retrospective questioning of the overall user experience, and a System Usability Scale (SUS). The field notes from the interviews were subjected to thematic analysis.

RESULTS

In total, 12 CPs were interviewed in stage 1, and 7 CPs participated in stage 2. The interview findings show that CPs are willing to report ADRs but face barriers from environmental, organizational, and IT infrastructures. Increasing ADR awareness, improving workplace practices, and implementing user-focused electronic reporting systems were seen as facilitators of ADR reporting. User testing of an existing system resulted in above average usability (SUS 68.57); however, functional and user interpretation issues were identified. Design elements such as a drop-down menu, free-text entry, checkbox, and prefilled data fields were perceived to be extremely useful for navigating the system and facilitating ADR reporting.

CONCLUSIONS

Existing reporting systems are not suited to report ADRs, or adapted to workflow, and are rarely used by CPs. Our study uncovered important contextual information for the design of future ADR reporting interventions. Based on our study, a multifaceted, theory-guided, user-centered, and best practice approach to design, implementation, and evaluation may be critical for the successful adoption of ADR reporting electronic interventions and patient safety. Future studies are needed to evaluate the effectiveness of theory-driven frameworks used in the design and implementation of ADR reporting systems.

Correlation of Postvaccination Fever With Specific Antibody Response to Severe Acute Respiratory Syndrome Coronavirus 2 BNT162b2 Booster and No Significant Influence of Antipyretic Medication

BACKGROUND

A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine booster elicits sufficient antibody responses that protect against coronavirus disease 2019, whereas adverse reactions such as fever have been commonly reported. Associations between adverse reactions and antibody responses have not been fully characterized, nor has the influence of antipyretic use.

METHODS

This is a prospective observational cohort study in Japan, following our prior investigation of BNT162b2 2-dose primary series. Spike-specific immunoglobulin G (IgG) titers were measured for SARS-CoV-2-naive hospital healthcare workers who received a BNT162b2 booster. The severity of solicited adverse reactions, including the highest body temperature, and self-medicated antipyretics were reported daily for 7 days following vaccination through a web-based self-reporting diary.

RESULTS

The data of 281 healthcare workers were available. Multivariate analysis extracted fever after the booster dose (β = .305, P < .001) as being significantly correlated with the specific IgG titers. The analysis of 164 participants with data from the primary series showed that fever after the second dose was associated with the emergence of fever after the booster dose (relative risk, 3.97 [95% confidence interval, 2.48-6.35]); however, the IgG titers after the booster dose were not associated with the presence or degree of fever after the second dose. There were no significant differences in the IgG titers by the use, type, or dosage of antipyretic medication.

CONCLUSIONS

These results suggest an independent correlation between mRNA vaccine-induced specific IgG levels and post-booster vaccination fever, without any significant influence of fever after the primary series. Antipyretic medications for adverse reactions should not interfere with the elevation of specific IgG titers.

The short term safety of COVID ‐19 vaccines in Australia: AusVaxSafety active surveillance, February – August 2021

Objective:

To assess the short term safety of the COVID‐19 vaccines Comirnaty (Pfizer–BioNTech BNT162b2) and Vaxzevria (AstraZeneca ChAdOx1) in Australia.

Design:

Prospective observational cohort study; online surveys by AusVaxSafety, a national active vaccine safety surveillance system, three and eight days after vaccination.

Setting, participants:

People aged 16 years or more who received COVID‐19 vaccines at sentinel vaccination hubs, general practices, or Aboriginal Community Controlled Health Organisation clinics, 22 February – 30 August 2021.

Main outcome measures:

Primary outcome: proportion of respondents who reported any adverse event following immunisation (AEFI) 0–3 days after vaccination. Secondary outcomes: proportions of respondents who reported specific adverse events or medical review for AEFI within seven days of vaccination; impact on usual daily activities; recovery.

Results:

4 851 480 people received COVID‐19 vaccines at participating sentinel sites during the study period (25% of all COVID‐19 vaccine doses administered in Australia to 30 August 2021). 3 035 983 people responded to both surveys (response rate, 62.6%); 35.9% of respondents reported one or more AEFI 0–3 days after Comirnaty dose 1, 54.7% after Comirnaty dose 2, 52.8% after Vaxzevria dose 1, and 22.0% after Vaxzevria dose 2. Local pain, fatigue, headache, and myalgia were the most frequently reported symptoms. After adjusting for demographic characteristics, vaccination site type, jurisdiction, and self‐reported medical conditions, the odds of reporting any AEFI were higher for women than men (range of adjusted odd ratios [aORs], by vaccine and dose, 1.53–1.84), for people with a history of anaphylaxis (aOR range, 1.28–1.45), and for people reporting certain underlying conditions, including obesity (aOR range, 1.15–1.75), immunodeficiency (aOR range, 1.04–2.24), or chronic inflammatory disease (aOR range, 1.05–1.75). 0.9% of respondents sought medical advice in the three days following vaccination, most frequently after Comirnaty dose 2 (1.4%) and Vaxzevria dose 1 (1.2%).

Conclusion:

AusVaxSafety active surveillance affirms the short term safety profile of Comirnaty and Vaxzevria vaccines in a large population sample during the first six months of the Australian COVID‐19 vaccination program.

A scoping review of active, participant-centred, digital adverse events following immunization (AEFI) surveillance: A Canadian immunization research network study

BACKGROUND

Post-licensure adverse events following immunization (AEFI) surveillance is conducted to monitor vaccine safety, such as identifying batch/brand issues and rare reactions, which consequently improves community confidence. The integration of technology has been proposed to improve AEFI surveillance, however, there is an absence of description regarding which digital solutions are successfully being used and their unique characteristics.

OBJECTIVES

The objectives of this scoping review were to 1) map the research landscape on digital systems used for active, participant-centred, AEFI surveillance and 2) describe their core components.

METHODS

We conducted a scoping review informed by the PRISMA Extension for Scoping Reviews (PRSIMA-ScR) guideline. OVID-Medline, Embase Classic + Embase, and Medrxiv were searched by a medical librarian from January 1, 2000 to January 28th, 2021. Two independent reviewers determined which studies met inclusion based on pre-specified eligibility criteria. Data extraction was conducted using pre-made tables with specific variables by one investigator and verified by a second.

RESULTS

Twenty-seven publications met inclusion, the majority of which came from Australia (n = 15) and Canada (n = 6). The most studied active, participant-centred, digital AEFI surveillance systems were SmartVax (n = 8) (Australia), Vaxtracker (n = 7) (Australia), and Canadian National Vaccine Safety (CANVAS) Network (Canada) (n = 6). The two most common methods of communicating with vaccinees reported were short-message-service (SMS) (n = 15) and e-mail (n = 14), with online questionnaires being the primary method of data collection (n = 20).

CONCLUSION

Active, participant-centred, digital AEFI surveillance is an area actively being researched as depicted by the literature landscape mapped by this scoping reviewWe hypothesize that the AEFI surveillance approach herein described could become a primary method of collecting self-reported subjective symptoms and reactogenicity from vaccinees, complementing existing systems. Future evaluation of identified digital solutions is necessary to bring about improvements to current vaccine surveillance systems to meet contemporary and future public health needs.

Differences and disparities in seasonal influenza vaccine, acceptance, adverse reactions, and coverage by age, sex, gender, and race

BACKGROUND

Influenza is a significant threat to public health worldwide. Despite the widespread availability of effective and generally safe vaccines, the acceptance and coverage of influenza vaccines are significantly lower than recommended. Sociodemographic variables are known to be potential predictors of differential influenza vaccine uptake and outcomes.

OBJECTIVES

This review aims to (1) identify how sociodemographic characteristics such as age, sex, gender, and race may influence seasonal influenza vaccine acceptance and coverage; and (2) evaluate the role of these sociodemographic characteristics in differential adverse reactions among vaccinated individuals.

METHODS

PubMed was used as the database to search for published literature in three thematic areas related to the seasonal influenza vaccine - vaccine acceptance, adverse reactions, and vaccine coverage.

RESULTS

A total of 3249 articles published between 2010 and 2020 were screened and reviewed, of which 39 studies were included in this literature review. By the three thematic areas, 17 studies assessed vaccine acceptance, 8 studies focused on adverse reactions, and 14 examined coverage of the seasonal influenza vaccine. There were also two studies that focused on more than one of the areas of interest.

CONCLUSION

Each of the four sociodemographic predictors - age, sex, race, and gender - were found to significantly influence vaccine acceptance, receipt and outcomes in this review.

Exposure to quadrivalent influenza vaccine during pregnancy: Results from a global pregnancy registry

BACKGROUND

The Fluzone® Quadrivalent (IIV4, Sanofi Pasteur) Pregnancy Registry was created to monitor vaccine safety during pregnancy (clinicaltrials.gov, NCT01945424). Here, we describe maternal, pregnancy, obstetrical and neonatal outcomes after vaccine exposure in pregnant women between August 2013 and September 2019.

METHODS

All women exposed to IIV4 during their pregnancy were eligible for inclusion. Outcomes were prospective (reported following vaccine exposure but before knowledge of pregnancy outcome ascertained through prenatal tests) or retrospective (prenatal tests were undertaken before the exposure was reported).

RESULTS

Among 239 IIV4 vaccine exposure reports received, there were 105 prospective and 10 retrospective reports of maternal adverse events (AEs). The most frequent prospectively reported maternal AEs were medication errors (expired product [n = 8, 3.8%]; extra dose [n = 7, 3.3%]) and injection site pain (n = 7, 3.3%). Among 62 prospectively reported pregnancy and obstetrical events with available follow-up information, seven AEs were reported, four (6.4%) of which were spontaneous abortions. A further seven AEs were reported among the 29 retrospective pregnancy and obstetrical events with available follow-up information. Among neonatal outcomes (15 prospective; 28 retrospective), >85% were reported as full-term births. One premature birth was reported prospectively. Four other neonatal AEs were reported, all retrospectively: two cases of talipes (club foot), one central nervous system anomaly and one atrial septal defect. All infants with available information had normal APGAR scores at 5 minutes.

CONCLUSIONS

The frequency of AEs following exposure to IIV4 during pregnancy did not indicate new safety concerns.

Early solicited adverse events following the BNT162b2 mRNA vaccination, a population survey from Saudi Arabia

Post rollout safety for the coronavirus disease vaccines is crucial and recommended. To explore the early solicited adverse events (AE) following BNT162b2 mRNA vaccination in Saudi Arabia, we distributed an online survey to adults vaccinated with BNT162b2 over the first week of June 2021, to collect data on first (V1), second doses (V2), symptoms, severity, and outcome after an informed consent was obtained. We recruited 3639 BNT162b2 vaccinated individuals, of which one-third had received two doses, 63.3% were female, 77% were healthy, and 89% had 18-55 years of age, while only 9.8% had a history of allergy. Overall, 50.3% had any AEs after any dose, especially those younger than 55 years of age, female, history of comorbidity, and when adjusted for age and gender, lung or cardiovascular diseases. Overall, the most common AE were pain at the injection site (44%), tiredness (39%), or body ache (31%). Compared to V1, a higher rate of post-V2 systemic AE (36% vs. 51%). Most AEs started very early (within 3 days), and rarely delayed in recovery (>2 weeks). Anti-pyretic was the most commonly used (51.7%), a third of which was unnecessary. Only 1.7% required hospital admission. By multivariate analysis, predictors for admission were the presence of lung or immunocompromising diseases. In conclusion, common AEs after BNT162b2 in the real world were generally mild, self-limiting, higher after the second dose, and largely mimicking that reported in clinical trials. The causality of these AE and the persistence of post-vaccination symptoms needs to be investigated further.

Safety, Immunogenicity, Efficacy and Effectiveness of Inactivated Influenza Vaccines in Healthy Pregnant Women and Children Under 5 Years: An Evidence-Based Clinical Review

Annual influenza vaccination is often recommended for pregnant women and young children to reduce the risk of severe influenza. However, most studies investigating the safety, immunogenicity, and efficacy or effectiveness of influenza vaccines are conducted in healthy adults. In this evidence-based clinical review, we provide an update on the safety profile, immunogenicity, and efficacy/effectiveness of inactivated influenza vaccines (IIVs) in healthy pregnant women and children <5 years old. Six electronic databases were searched until May 27, 2021. We identified 3,731 articles, of which 93 met the eligibility criteria and were included. The IIVs were generally well tolerated in pregnant women and young children, with low frequencies of adverse events following IIV administration; however, continuous vaccine safety monitoring systems are necessary to detect rare adverse events. IIVs generated good antibody responses, and the seroprotection rates after IIVs were moderate to high in pregnant women (range = 65%-96%) and young children (range = 50%-100%), varying between the different influenza types/subtypes and seasons. Studies show vaccine efficacy/effectiveness values of 50%-70% in pregnant women and 20%-90% in young children against lab-confirmed influenza, although the efficacy/effectiveness depended on the study design, host factors, vaccine type, manufacturing practices, and the antigenic match/mismatch between the influenza vaccine strains and the circulating strains. Current evidence suggests that the benefits of IIVs far outweigh the potential risks and that IIVs should be recommended for pregnant women and young children.

Enhanced passive safety surveillance of a trivalent and a quadrivalent influenza vaccine in Denmark and Finland during the 2018/2019 season

The European Medicines Agency requires Enhanced Passive Safety Surveillance (EPSS) for all seasonal influenza vaccines. Here, we report the EPSS results for the trivalent inactivated influenza vaccine (IIV3; Vaxigrip®) and the quadrivalent inactivated influenza vaccine (IIV4; VaxigripTetra^TM) during the 2018/19 influenza season in Denmark and Finland. The primary objective was to estimate the rates of suspected adverse reactions (ARs) occurring within 7 days following routine vaccination. Between October and November 2018, 1000 safety report cards (SRCs) for IIV3 were distributed in Denmark, and 996 SRCs for IIV4 were distributed in Finland. Participants were instructed to report any ARs by telephone or e-mail using the information provided on the SRC. All participants vaccinated with IIV3 were aged ≥18 years. Most participants vaccinated with IIV4 (95.5%) were aged 18 − 65 years, 2.2% were aged 6 months to 17 years, and 2.3% were aged >65 years. Fifty-five ARs were reported by 12 participants (1.2%) vaccinated with IIV3 and 162 ARs were reported by 53 participants (5.3%) vaccinated with IIV4. The most frequent ARs were vaccination site pain and fever for IIV3, and vaccination site pain, vaccination site inflammation, myalgia, and headache for IIV4. The 2018/19 AR rates for IIV3 were comparable to 2017/18 rates. The 2018/19 AR rates for IIV4 were higher than those in 2017/18 but were still lower than the expected AR rates listed in the IIV4 Summary of Product Characteristics. In conclusion, the 2018/19 EPSS showed no clinically significant change from the expected safety profiles of IIV3 and IIV4 vaccines.

Safety of live attenuated herpes zoster vaccine in Australian adults 70-79 years of age: an observational study using active surveillance

OBJECTIVES

To assess the safety of live attenuated herpes zoster vaccine live (ZVL) through cumulative analysis of near real-time, participant-based active surveillance from Australia's AusVaxSafety system.

DESIGN AND SETTING

ZVL was funded in Australia for adults aged 70 years from November 2016, with a time-limited catch up programme for those up to 79 years. This cohort study monitored safety in the first two programme years through active surveillance at 246 sentinel surveillance immunisation sites.

PARTICIPANTS

Adults aged 70-79 years vaccinated with ZVL who responded to an opt-out survey sent via automated short message service (SMS) 3 days following vaccination (n=17 458) or contributed supplementary data through a separate, opt-in online survey at 16 and 24 days following vaccination (n=346).

PRIMARY AND SECONDARY OUTCOME MEASURES

Rates of overall and prespecified adverse events following immunisation (AEFI) by sex, concomitant vaccination and underlying medical condition. Signal detection methods (fast initial response cumulative summation and Bayesian updating analyses) were applied to reports of medical attendance.

RESULTS

The median age of participants was 72 years; 53% were female. The response rate following automated SMS was high (73% within 7 days of vaccination). Females were more likely than males to report any adverse event within 7 days of vaccination (RR 2.07, 95% CI 1.86 to 2.31); injection site reaction was the most commonly reported (2.3%, n=377). Concomitant vaccination was not associated with higher adverse event rates (RR 1.05, 95% CI 0.93 to 1.18). Rates of medical attendance were low (0.3%) with no safety signals identified. Supplementary opt-in survey data on later onset adverse events did not identify any difference in AEFI rates between those with and without underlying medical conditions.

CONCLUSIONS

ZVL has a very good safety profile in the first week after vaccination in older adults. Active, participant-based surveillance in this primary care cohort is an effective method to monitor vaccine safety among older adults and will be used as a key component of COVID-19 vaccine safety surveillance in Australia.

Post-vaccination healthcare attendance rate as a proxy measure for syndromic surveillance of adverse events following immunisation

OBJECTIVE

This study explored whether all-cause healthcare attendance rate post-vaccination could detect the two historical influenza safety episodes occurring in 2010 and 2015 using a large de-identified general practitioner (GP) consultations dataset.

METHODS

A retrospective observational cohort study was conducted using GP consultation data routinely collected from 2008 to 2017 in Victoria, Australia. Post-vaccination GP consultation rates were monitored, over a 22-week surveillance period each year that aligned with each year's influenza vaccination season, using the Observed minus Expected (O-E) and the Log-Likelihood Ratio (LLR) CUSUM charts. Days 1-7 post-vaccination were considered as the risk period. The LLR CUSUM was designed to detect both a 50% and two-fold rise in the odds of the baseline post-vaccination GP consultation rates.

RESULTS

Over the 10-year study period, more than 1.5 million seasonal influenza vaccines doses were administered to 295,091 persons. Overall, 1.29% had a GP consultation within one week of vaccination, but 98.53% of the consultations occurred in days 1-3 post-vaccination. The LLR CUSUM chart detected significant increases in the weekly rates of post-vaccination GP consultation in 2010 in children aged under ten years and in 2015 in adults aged 19-64 years. These increases were aligned by week, but one week earlier and by age category, with the historical adverse events following immunisation (AEFI) signals occurring in 2010 and 2015. However, in the absence of historical AEFI signals, increased rates of post-vaccination GP consultations were identified in three of the eight influenza vaccination years.

CONCLUSION

The crude post-vaccination healthcare attendance rate has the potential to offer a sensitive proxy to monitor vaccine safety signal. Implications for public health: Vaccine safety monitoring using syndromic indicator has the potential to augment the existing surveillance systems as part of an integrated vaccine safety monitoring approach.

Consumer acceptability and validity of m-Health for the detection of adverse events following immunization - The Stimulated Telephone Assisted Rapid Safety Surveillance (STARSS) randomised control trial

INTRODUCTION

Monitoring for adverse events following immunisation (AEFI) is critical for vaccine pharmacovigilance. Given the global and expanding availability of mobile phones their utility for consumer-based vaccine safety surveillance is of interest but little is known about consumer acceptability. This study nested within the Stimulated Telephone Assisted Rapid Safety Surveillance (STARSS) randomised control trial sought to evaluate the acceptability of SMS for AEFI surveillance.

METHODS

The primary STARSS study was a multi-centre RCT evaluating the efficacy of repeated SMS prompts for AEFI surveillance with participants being adult vaccinees or parents of children receiving any vaccine. This nested study enrolled primary RCT participants who completed a detailed computer assisted telephone interview to determine their attitudes towards SMS-based surveillance and ascertain their knowledge and attitudes toward vaccine safety, efficacy, data privacy and use of electronic health records. Attitudes to surveillance and related behaviour were used as measures of acceptability.

RESULTS

20% (1200/6555) of the participants were enrolled and 1139 completed the full-length questionnaire. 96% indicated that SMS-based surveillance after immunisation to check the safety of the vaccine "should be done" but 62% of all respondents said it should be done but consent should be sought first. Neither vaccine safety attitudes nor attitudes toward privacy were associated with opposition to SMS-based surveillance. In terms of SMS related behaviour demographic rather than attitudinal factors were associated with non-compliance.

CONCLUSION

Overall, the attitude towards SMS-based surveillance was very favourable. Experiencing the SMS surveillance has the effect of reducing opposition to an SMS surveillance system, and at the same time increasing the likelihood of a preference for prior consent. Detection of a vaccine safety signal could be impeded in particular demographic groups who are non-compliant and we should undertake further research to understand why these groups are non-compliant and how this can be improved.

Efficacy of m-Health for the detection of adverse events following immunization - The stimulated telephone assisted rapid safety surveillance (STARSS) randomised control trial

INTRODUCTION

Passive surveillance is recommended globally for the detection of adverse events following immunisation (AEFI) but this has significant challenges. Use of Mobile health for vaccine safety surveillance enables a consumer-centred approach to reporting. The Stimulated Telephone Assisted Rapid Safety Surveillance (STARSS) a randomised control trial (RCT) sought to evaluate the efficacy and acceptability of SMS for AEFI surveillance.

METHODS

Multi-centre RCT, participants were adult vaccinees or parents of children receiving any vaccine at a trial site. At enrolment randomisation occurred to one of two SMS groups or a control group. Prompts on days 2, 7 and 14 post-immunisation, were sent to the SMS group, to ascertain if a medical event following immunisation (MEFI) had occurred. No SMS's were sent to the control participants. Those in the SMS who notified an MEFI were pre-randomised to complete a computer assisted telephone interview or a web based report to determine if an AEFI had occurred whilst an AEFI in the controls was determined by a search for passive reports. The primary outcome was the AEFI detection rate in the SMS group compared to controls.

RESULTS

We enrolled 6,338 participants, who were equally distributed across groups and who received 11,675 vaccines. The SMS group (4,225) received 12,675 surveillance prompts with 9.8% being non-compliant and not responding. In those that responded 90% indicated that no MEFI had been experienced and 184 had a verified AEFI. 6 control subjects had a reported AEFI. The AEFI detection rate was 13 fold greater in the SMS group when compared with controls (4.3 vs 0.3%).

CONCLUSION

We have demonstrated that the STARSS methodology improves AEFI detection. Our findings should inform the wider use of SMS-based surveillance which is particularly relevant since establishing robust and novel pharmacovigilance systems is critical to monitoring novel vaccines which includes potential COVID vaccines.

SAEFVIC: Surveillance of adverse events following immunisation (AEFI) in Victoria, Australia, 2018

Background

SAEFVIC is the Victorian surveillance system for adverse events following immunisation (AEFI). It enhances passive surveillance by also providing clinical support and education to vaccinees and immunisation providers. This report summarises surveillance, clinical and vaccine pharmacovigilance activities of SAEFVIC in 2018.

Methods

A retrospective observational cohort study of AEFI reports received by SAEFVIC in 2018, compared with previous years since 2008. Data were categorised by vaccinee demographics of age, sex, pregnancy and Indigenous status, vaccines administered and AEFI reactions reported. Age cohorts were defined as infant (0-12 months); young child (1-4 years); school-aged (5-17 years); adult (18-64 years); and older person (65+ years). Proportional reporting ratios were calculated for signal investigation of serious adverse neurological events with all vaccines and with influenza vaccines. Clinical support services and educational activities are described.

Results

SAEFVIC received 1730 AEFI reports (26.8 per 100,000 population), with 9.3% considered serious. Nineteen percent (n = 329) attended clinical review. Annual AEFI reporting trends increased for infants, children and older persons, but were stable for school-aged and adult cohorts. Females comprised 55% of all reports and over 80% of reports among adults. There were 17 reports of AEFI in pregnant women and 12 (0.7%) in persons identifying as Indigenous Australians. A possible signal regarding serious adverse neurological events (SANE) was detected, but was not supported by signal validation testing. A clinical investigation is ongoing. Two deaths were reported coincident to immunisation with no evidence of causal association.

Conclusion

SAEFVIC continues to provide robust AEFI surveillance supporting vaccine safety monitoring in Victoria and Australia, with new signal detection and validation methodologies strengthening capabilities.

2017/18 and 2018/19 seasonal influenza vaccine safety surveillance, Canadian National Vaccine Safety (CANVAS) Network

Background

The Canadian National Vaccine Safety (CANVAS) network monitors the safety of seasonal influenza vaccines in Canada.

Aim

To provide enhanced surveillance for seasonal influenza and pandemic influenza vaccines.

Methods

In 2017/18 and 2018/19 influenza seasons, adults (≥ 15 years of age) and parents of children vaccinated with the seasonal influenza vaccine participated in an observational study using web-based active surveillance. Participants completed an online survey for health events occurring in the first 7 days after vaccination. Participants who received the influenza vaccine in the previous season, but had not yet been vaccinated for the current season, were unvaccinated controls.

Results

In 2017/18, 43,751 participants and in 2018/19, 47,798 completed the online safety survey. In total, 957 of 30,173 participants vaccinated in 2017/18 (3.2%; 95% confidence interval (CI): 3.0–3.4) and 857 of 25,799 participants vaccinated in 2018/19 (3.3%; 95% CI: 3.1–3.5) reported a health problem of sufficient intensity to prevent their normal daily activities and/or cause them to seek medical care (including hospitalisation). This compared to 323 of 13,578 (2.4%; 95% CI: 2.1–2.6) and 544 of 21,999 (2.5%; 95% CI: 2.3–2.7) controls in each respective season. The event rate in vaccinated adults and children was higher than the background rate and was associated with specific influenza vaccines. The higher rate of events was associated with systemic symptoms and migraines/headaches.

Conclusion

In 2017/18 and 2018/19, higher rates of events were reported following seasonal influenza vaccination than in the pre-vaccination period. This signal was associated with several seasonal influenza vaccine products.

Active SMS-based surveillance of adverse events following immunisation with influenza and pertussis-containing vaccines in Australian pregnant women using AusVaxSafety

BACKGROUND

Maternal immunisation is important to protect both mother and baby, but safety concerns can lead to low uptake. AusVaxSafety participant-based surveillance actively monitors adverse events following immunisation (AEFI) in Australia. We aimed to analyse AEFI in the days following vaccination with seasonal inactivated influenza vaccine (IIV) and/or reduced antigen diphtheria-tetanus-acellular pertussis vaccine (dTpa) in pregnant women in Australia.

METHODS

De-identified AEFI reports were solicited from vaccine recipients via automated SMS survey (using SmartVax software) following routine vaccination with IIV and/or dTpa at 219 national sentinel surveillance sites from 2015 to 2018. AEFI rates were compared by vaccine group (IIV alone, dTpa alone, or IIV and dTpa together), vaccine brand, trimester (IIV only) and vaccination period (April to August 2016-2018; IIV only). Women who had two vaccination encounters during surveillance were identified and AEFI rates compared for each dose.

RESULTS

Among 13,758 participants, overall AEFI rates were lower following IIV (4.9%) than dTpa (6.4%) or IIV and dTpa given concomitantly (7.4%). The AEFI profile was similar for both vaccines, with injection site reactions, tiredness, and headache most commonly reported. Injection site pain and swelling/redness were significantly more common in women who received dTpa than IIV. Reports of medical attendance following immunisation were similar (0.3%) for each vaccine group. AEFI rates did not differ by IIV brand (FluQuadri®, Fluarix® Tetra), dTpa brand (Boostrix®, Adacel®), or by trimester. Among women with sequential dTpa vaccinations, 6.0% (7/116) had an AEFI following their second dTpa dose.

CONCLUSIONS

Self-reported AEFI rates did not differ by trimester (IIV), or by vaccine brand (IIV or dTpa). Concomitant influenza and pertussis vaccination was associated with more frequent, but low rates of minor, expected AEFI. These real world 'citizen science-based' data provide further reassuring evidence of the safety of maternal vaccination.

Comparative Postmarket Safety Profile of Adjuvanted and High-Dose Influenza Vaccines in Individuals 65 Years or Older

IMPORTANCE

Every year, influenza vaccines are administered to millions of people worldwide to reduce morbidity and mortality from influenza. As new vaccine formulations are increasingly used, monitoring and comparing safety, in addition to vaccine effectiveness, in target populations are essential.

OBJECTIVE

To assess the postmarketing safety profile of 2018 Southern Hemisphere influenza vaccines, particularly 2 new enhanced trivalent inactivated influenza vaccines: an adjuvanted trivalent inactivated influenza vaccine (aIIV3) and high-dose trivalent inactivated influenza vaccine (HD-IIV3), among Australian individuals 65 years or older.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used solicited short message service-based self-reported survey data on adverse events occurring within 3 to 5 days after receipt of an influenza vaccination. Participants included individuals 65 years or older who received routinely recommended influenza vaccines at 1 of 265 sentinel immunization sites, including primary care, hospital, and community-based clinics, participating in Australia's AusVaxSafety active vaccine safety surveillance system from April 1 to August 31, 2018. Data were analyzed from September 1, 2018, to June 30, 2019.

EXPOSURE

Any licensed 2018 influenza vaccine administered in clinical practice.

MAIN OUTCOMES AND MEASURES

Rates (overall, by brand, and by concomitant vaccine receipt) of adverse events, including medical attendance as a proxy for serious adverse events.

RESULTS

Of 72 013 individuals 65 years or older who received an influenza vaccine in 2018, 50 134 individuals (69.6%) responded to the initial survey regarding adverse events experienced after vaccination (median [interquartile range] age, 71 [68-76] years; 27 056 [54.0%] women). Most individuals received an enhanced trivalent inactivated influenza vaccine, including 28 003 individuals (55.9%) who received aIIV3 and 19 306 individuals (38.5%) who received HD-IIV3; 2208 individuals (4.4%) received a quadrivalent inactivated influenza vaccine. Individuals who received HD-IIV3 reported significantly higher rates of any adverse event compared with individuals who received aIIV3 (1716 individuals [8.9%] vs 1796 individuals [6.4%]; P < .001) as well as specific adverse events, including fever (195 individuals [1.1%] vs 164 individuals [0.6%]; P < .001), injection site pain (383 individuals [2.1%] vs 350 individuals [1.3%]; P < .001), and injection site swelling or redness (256 individuals [1.4%] vs 248 individuals [0.9%]; P < .001). Adverse event rates reported by those receiving any quadrivalent inactivated influenza vaccine were similar to rates reported by those receiving aIIV3. Rates of medical care seeking for adverse events associated with aIIV3 and HD-IIV3 were low and comparable (80 individuals [0.3%] vs 56 individuals [0.3%]; P = .91).

CONCLUSIONS AND RELEVANCE

The findings of this large-scale participant-based postmarketing assessment of the safety of 2 new enhanced influenza vaccines used in individuals 65 years or older provide reassuring near-real-time and cumulative data to inform and support confidence in ongoing vaccine use.

Safety of live attenuated herpes zoster vaccine in adults 70-79 years: A self-controlled case series analysis using primary care data from Australia's MedicineInsight program

BACKGROUND

Australia introduced a funded shingles vaccination program for older adults in November 2016, administered predominantly in primary care clinics. MedicineInsight, a nationally representative primary care database, was used to investigate the risk of pre-specified outcomes following live attenuated herpes zoster vaccine (ZVL) in Australia.

METHODS

Individuals aged 70-79 years who received ZVL between 1 November 2016 and 31 July 2018 were identified from MedicineInsight. The self-controlled case series (SCCS) method was used to estimate the seasonally-adjusted relative incidence (RI) of seven pre-specified outcome events (injection site reaction (ISR) [positive control], burn [negative control], myocardial infarction (MI), stroke, rash, rash with an antiviral prescription, and clinical attendance) during a plausible post-vaccination at-risk window compared with times distant from vaccination. Sensitivity analyses examined the effect of common concomitant vaccinations and restriction to first outcome events.

RESULTS

A total of 332,988 vaccination encounters among 150,054 individuals were identified during the study period; over 2 million clinical attendances were observed. There was an increased RI of ISR in the seven days following ZVL (RI = 77.4, 95% CI 48.1-124.6); the RI of clinical attendance (RI = 0.94, 95% CI 0.94-0.95) and stroke (RI = 0.58, 95% CI 0.44-0.78) were lower in the 42 days following administration of ZVL compared to control periods. There was no evidence of a change in the RI of MI (RI = 0.74, 95% CI 0.41-1.33), rash (RI = 0.97, 95% CI 0.88-1.08), or rash with antiviral prescription (RI = 0.83, 95% CI 0.62-1.10) in the 42 days following ZVL compared to control periods.

CONCLUSION

No new safety concerns were identified for ZVL in this study based on a novel, Australian primary care data source. An expected increased risk of ISR was identified; findings in relation to cardiovascular disease were reassuring but require confirmation using additional data, including hospital records.

Timeliness of signal detection for adverse events following influenza vaccination in young children: a simulation case study

OBJECTIVES

To determine how soon after commencement of the seasonal influenza vaccination programme, the AusVaxSafety active vaccine safety surveillance system, currently in use across Australia, would have detected a safety signal had it been operating in 2010 when there was an unprecedented number of febrile seizures in young children associated with one specific influenza vaccine brand, Fluvax (CSL Biotherapies).

DESIGN

Simulation study.

SETTING

Western Australian vaccine influenza coverage and adverse event surveillance data.

OUTCOME MEASURES

Simulated solicited responses from caregivers who would have received an SMS survey about adverse events experienced following seasonal influenza vaccination of their children aged 6 months to <5 years.

PARTICIPANTS

None.

RESULTS

We estimated a >90% probability of a safety signal being detected by AusVaxSafety based on solicited reports for either fever or medical attendance at or before the week ending 28 March 2010, 3 weeks after the start of vaccine distribution. Suspension of the national paediatric influenza vaccination programme as a result of the passive adverse events surveillance operating at the time did not occur until 23 April 2010.

CONCLUSIONS

Active vaccine safety surveillance leading to rapid detection of a safety signal would likely have resulted in earlier suspension of Fluvax from the vaccination programme, prevention of many febrile convulsions and maintenance of public confidence in influenza vaccination for young children.

Adverse Events Following Measles-Mumps-Rubella-Varicella Vaccination and the Case of Seizures: A Post Marketing Active Surveillance in Puglia Italian Region, 2017-2018

Since 2012, the Italian Ministry of Health has recommended to improve the surveillance of adverse events following the measles-mumps-rubella-varicella (MMRV) tetravalent vaccine that was provided in the official immunization schedule of some Italian regions for children during the second year of life. This recommendation was based on data from some surveys that showed an additional risk of seizure following the administration of this vaccine. Responding to the Ministry commitment, the Puglia Region launched, from May 2017 to November 2018, a post-marketing active surveillance program of adverse events following MMRV immunization (AEFIs). Immunized children (second year of life) were enrolled on a voluntary basis, AEFIs diaries were used, and their parents were interviewed 25 days after the immunization. There were 2540 children enrolled; 2149/2540 (84.6%) completed the post-vaccination follow-up. Of these, 992 AEFIs were registered with a reporting rate of 46.2 × 100 doses: 883/992 (89.0%) AEFIs were not serious, while 109/992 (11.0%) were serious. For serious AEFIs, the evaluation of causality assessment was performed using the algorithm proposed by the World Health Organisation (WHO): 82/109 consistent causal associations to MMRV immunization were detected (reporting rate of consistent AEFIs: 3.8 × 100 follow-up). All serious AEFIs consistently associated with immunization resulted completely resolved at the follow-up. The reporting rate of seizure consistently associated with immunization was 0.05 × 100, lower than data previous published in the literature that did not report the causality assessment. Because no emerging signals were detected, our data from the active surveillance program confirmed the safety profile of the MMRV vaccine.

Challenges in implementing yearly enhanced safety surveillance of influenza vaccination in Europe: lessons learned and future perspectives

Seasonal influenza vaccines are frequently reformulated, leading to specific challenges for continuous benefit/risk monitoring. In 2014, the European Medicines Agency started requiring annual enhanced safety surveillance (ESS). This article provides a perspective on ESS studies conducted ever since and aims to map existing initiatives used to monitor adverse events following influenza immunization. Of 11 ESS studies, reporting surveillance data of at least five different vaccine brands during four seasons, all were able to rapidly capture vaccine-specific adverse events of interest reports. However, challenges have been identified during study implementation, including recruitment of sufficient participants, enrolling younger age groups, collecting data of vaccine batch numbers, comparing observed with expected rates and achieving adequate return of reported events. Harmonizing safety monitoring standards across countries, and bridging between routine pharmacovigilance and ESS, is likely to allow more comprehensive assessments of influenza vaccine safety, requiring close collaboration between regulators, public health, and manufacturers.

Enhanced passive safety surveillance of three marketed influenza vaccines in the UK and the Republic of Ireland during the 2017/18 season

Safety surveillance is required for each season’s influenza vaccines to rapidly detect and evaluate potential new safety concerns before the peak period of immunization. Here we report the results of an enhanced passive safety surveillance for a trivalent split-virion inactivated influenza vaccine (IIV3; Vaxigrip®), an intradermal version of this vaccine (IIV3-ID; Intanza® 15 µg), and a recently licensed quadrivalent version (IIV4; VaxigripTetra^TM) during the 2017/18 influenza season in the UK and Republic of Ireland. The primary objective was to determine the rates of adverse reactions (ARs) occurring within 7 days following routine vaccination. Between September and November 2017, 979 safety report cards were distributed to vaccinees receiving IIV3-ID, 1005 to those receiving IIV3, and 957 to those receiving IIV4. At least one AR was reported by 28 participants (2.9%) vaccinated with IIV3-ID, 14 participants (1.4%) vaccinated with IIV3, and 20 participants (2.1%) vaccinated with IIV4. The most frequent ARs were injection-site reactions and headache. One participant vaccinated with IIV3-ID reported two suspected serious ARs (dyskinesia and a shock symptom), although these could not be confirmed as vaccine-related. Rates of ARs for IIV3 and IIV3-ID for 2017/18 did not differ from the 2016/17 rates. For IIV4, in its first season since licensure, AR frequencies were similar to those in the Summary of Product Characteristics. In conclusion, no change was found compared to the known or expected AR rates for IIV3, IIV3-ID, or IIV4 during the 2017/18 season.