Surveillance of adverse events following immunisation in Australia annual report, 2019

Adverse events following immunisation: Prospective cohort study evaluating Australian children presenting to specialist immunisation clinics

OBJECTIVE

Prior experience of an adverse event following immunisation is a known barrier to vaccination. Limited Australian data evaluating adverse event recurrence among children exists to inform clinical decisions. We aimed to assess adverse event following immunisation recurrence among children with prior adverse events and to evaluate if family history increased adverse event risk.

METHODS

A prospective cohort study was conducted from March 3rd until August 18th, 2023. Children ≤ 16 years with prior adverse events following immunisation in themselves or family were recruited from specialist immunisation clinics at two quaternary paediatric hospitals. Adverse event outcomes were collected via surveys administered at presentation, three, and eight days post vaccination, and analysed by key characteristics and potential risk factors.

RESULTS

Forty three of forty nine (43/49, 87.8 %) children enrolled received further vaccines. Of those who completed the follow up surveys, 50.0 % (16/32) reported an adverse event. Recurrence of prior adverse events occurred for 23.3 % (10/43, 95 % CI: 11.8 % - 38.6 %) of the cohort. Two of twelve (2/12, 16.7 %) participants with prior serious adverse events who received further vaccines reported a serious adverse event recurrence. No post review serious adverse events were observed in children with prior non serious adverse events. Neurological conditions were a risk factor for prior (neurological condition 3/3 versus no neurological condition 2/40, p < 0.001) and post review (neurological condition 2/3 versus no neurological condition 0/28, p = 0.006) post vaccination seizures. Family history had no relationship to post review adverse events (family history 5/8 versus no family history 11/23, p = 0.685).

CONCLUSION

Revaccination is safe for the majority of children with a personal or family history of adverse event following immunisation.

Review of the health impact of the oral rotavirus vaccine program in children under 5 years in Australia: 2006 - 2021

Oral rotavirus vaccines were incorporated into the National Immunisation Program (NIP) for all Australian infants in July 2007. Initially each of the eight jurisdictions implemented Rotarix or RotaTeq rotavirus vaccine, however from July 2017 all states and territories have administered Rotarix only. This review evaluates the health impact of the oral rotavirus vaccine program for Australian children less than 5 years old over the first 15 years of the rotavirus vaccine program, observing long-term changes in rotavirus-related health care attendances, public health notifications, and vaccine effectiveness and safety data for both Rotarix and RotaTeq rotavirus vaccines. We searched Medline for studies published between January 2006 and May 2022 using the search terms 'rotavirus', 'rotavirus vaccine' and 'Australia'. Of 491 items identified, 76 items - 36 peer-reviewed articles and 40 reports - were included in the review. We found evidence that the introduction of the oral rotavirus vaccine program in Australia was associated with a prompt reduction in rotavirus-coded and all-cause gastroenteritis hospitalisations of vaccine-eligible children. In the context of less complete coverage, reduced vaccine timeliness and lower vaccine effectiveness, a less substantial and inconsistent reduction in severe rotavirus disease was observed among Aboriginal and Torres Strait Islander children, particularly those living in rural and remote northern Australia. Additional studies report no evidence for the emergence of non-vaccine serotypes and/ or replacement serotypes in Australia during the vaccine era. While the health impact for young children and consequent cost-savings of the oral rotavirus vaccine program have been high, it is important to find strategies to improve rotavirus vaccine impact for Aboriginal and Torres Strait Islander populations to ensure health benefits for all Australian children.

Real-world safety profile of the 9-valent human papillomavirus vaccine: A study in Zhejiang, China from 2019 to 2021

The safety profile of the 9-valent human papillomavirus vaccine (9vHPV) was evaluated based on the reporting rate of adverse events following immunization (AEFI) obtained from the passive surveillance data in Zhejiang. The 9vHPV AEFI reports in Zhejiang were collected and reviewed from the National Adverse Event Following Immunization Surveillance System (NAEFISS) from 2019 to 2021. Reporting rates of AEFI were analyzed under multiple aspects, including age, city, number of vaccinations, AEFI categories, and diagnosis categories. This study used the reporting odds ratio (ROR) for anomalous signal assessment. The NAEFISS collected 331 AEFI reports after administering 1,064,851 doses of 9vHPV, with a crude AEFI rate of 3.12/10,000 doses. The third dose had the highest reporting rate of minor vaccine-related reaction (n = 80, 3.06 per 10,000), followed by the first dose (n = 134, 2.98 per 10,000), and second dose (n = 76, 2.15 per 10,000). Fever/redness/induration was the most common minor adverse event (281 records, 2.64/10,000 doses). Nine cases of urticaria, ten cases of allergic rash, and ten cases of syncope were recorded. This study found a positive signal association between 9vHPV immunization and adverse events such as syncope, encephalitis, sterile abscess, and urticaria. This study did not identify any new emerging safety concerns. In the future, more research is needed to validate and further explore adverse reactions associated with 9vHPV.

Vaccinations in patients with multiple sclerosis: a real-world, single-center experience

Vaccines prevent infections in patients with multiple sclerosis (MS). Though recommendations regarding vaccinating patients with MS have been recently published, real-world data regarding vaccines' planning in patients receiving disease-modifying drugs (DMDs) for MS are missing. Our aim was, therefore, to describe vaccination coverage rates, timing-proposal and safety in real-life vaccinating patients with MS undergoing DMDs before the start of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination campaign. Patients followed at our MS-center were referred to individualized immunization-programs customized to Italian recommendations, patients' risks, immunity to exanthematic diseases, ongoing DMDs, or therapy-start urgency. Disease-activity stated the need for an essential immunization-cycle, whose core was composed by four vaccines: meningococcal-B, pneumococcal conjugated, Haemophilus influenzae B, and meningococcal-ACWY vaccines. Vaccines were administered prior to the planned DMD-start when possible, inactivated-vaccines >2 weeks and live-vaccines >4 weeks before treatment-start. Patients received a 6-months clinical-/radiological-follow-up after immunization. One-hundred and ninety-five patients were vaccinated between April 2017 and January 2021. 124/195 (63.6%) started a vaccination-program before therapy-start/-switch and 108/124 (87.1%) effectively completed immunization before new therapy-start without any delay. The time needed for immunization-conclusion reached a median of 27 (confidence interval 22) days in 2020. No increase in clinical-/radiological-activity 3-/6-months after immunization was noted. In conclusion, our study confirmed feasibility and safety of a vaccination-protocol in patients with MS whose duration resulted in a median of 27 days.

A Comparison with Adverse Events Following Immunization Associated with Sabin-Strains and Salk-Strains Inactivated Polio Vaccines in Zhejiang Province, China

Objectives: One dose of Sabin-strains inactivated polio vaccine (IPV) was introduced into the Chinese immunization program on 1 May 2016. This study aimed to evaluate the safety of Sabin-strains IPV and provide a comparison with conventional Salk-strains IPV. Methods: Adverse events following immunization (AEFI) records associated with Sabin-strains IPV and Salk-strains IPV were extracted from the national AEFI surveillance system (NAEFISS) from 1 May 2016 to 31 December 2020. The vaccination information on Sabin-strains IPV and Salk-strains IPV during the same period was obtained from the Zhejiang provincial immunization information system. Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, and reaction categories and were compared between Sabin-strains IPV and Salk-strains IPV. Results: In total, 3,861,758 doses of Sabin-strains IPV and 1,018,604 doses of Salk-strains IPV were administered during the study period. The overall AEFI reporting rate for Sabin-strains IPV (3.96/10,000 doses) was significantly lower than that for Salk-strains IPV (5.03/10,000 doses) due to the reporting rate of the minor vaccine product-related reaction following Sabin-strains IPV was significantly lower than that for Salk-strains IPV (2.76/10,000 doses vs. 3.83/10,000 doses). The most frequently reported symptoms/signs were fever, induration/swelling, and rash/urticaria. The most frequently reported serious AEFI with a causal relationship was febrile convulsion, with the reporting rates of 0.10/10,000 doses for Sabin-strains IPV and 0.08/10,000 doses for Salk-strains IPV. No significant difference was found in the reporting rates of the other serious AEFI between the two types of IPV. Conclusion: Most of the AEFI following Sabin-strains IPV and Salk-strains IPV were mild and common adverse reactions. The reporting rate of serious AEFI was not significantly different between Sabin-strains IPV and Salk-strains IPV. Sabin-strains IPV had a favorable safety profile and could be widely used.