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

Herpes zoster vaccine safety in the Aotearoa New Zealand population: a self-controlled case series study

In Aotearoa New Zealand, zoster vaccine live is used for the prevention of zoster and associated complications in adults. This study assessed the risk of pre-specified serious adverse events following zoster vaccine live immunisation among adults in routine clinical practice. We conducted a self-controlled case series study using routinely collected national data. We compared the incidence of serious adverse events during the at-risk period with the control period. Rate ratios were estimated using Conditional Poisson regression models. Falsification outcomes analyses were used to evaluate biases in our study population. From April 2018 to July 2021, 278,375 received the vaccine. The rate ratio of serious adverse events following immunisation was 0·43 (95% confidence interval [CI]: 0·37-0·50). There was no significant increase in the risk of cerebrovascular accidents, acute myocardial infarction, acute pericarditis, acute myocarditis, and Ramsay-Hunt Syndrome. The herpes zoster vaccine is safe in adults in Aotearoa New Zealand.

Disseminated varicella zoster virus infection following live attenuated herpes zoster vaccine: descriptive analysis of reports to Australia's spontaneous vaccine pharmacovigilance system, 2016-2020

OBJECTIVES

To examine the reported incidence and features of disseminated varicella zoster virus (VZV) infection following live attenuated herpes zoster vaccine live (ZVL: Zostavax, Merck) in immunocompromised people in Australia.

DESIGN AND SETTING

ZVL was funded in 2016 in Australia for people aged 70 years, with a catch-up programme for those 71-79 years. From 2016 to 2020, three deaths due to disseminated vaccine-strain VZV infection occurred following inadvertent ZVL administration in individuals with varying levels of immunocompromise. This descriptive study examined 4 years of national surveillance data reported to the Therapeutic Goods Administration's Adverse Event Monitoring System (AEMS). Denominator data for rates were from doses recorded in the Australian Immunisation Register.

PARTICIPANTS

Individuals vaccinated between 1 November 2016 and 31 December 2020 who experienced adverse event(s) following immunisation (AEFI) after ZVL recorded in the AEMS.

PRIMARY AND SECONDARY OUTCOME MEASURES

Rates and outcomes of confirmed (Oka strain positive) or probable disseminated VZV infection, and inadvertent administration of ZVL in immunocompromised individuals.

RESULTS

854 AEFI were reported from 1 089 966 doses of ZVL administered (78.4 per 100 000 doses). Of those, 14 were classified as confirmed (n=6, 0.55 per 100 000) or probable (n=8) disseminated VZV infection. The confirmed cases were all hospitalised, and most (5/6) were immunocompromised; three cases died. Thirty-seven individuals were reported as vaccinated despite a contraindication due to immunocompromise (3.4 per 100 000), with 12/37 (32%) hospitalised.

CONCLUSIONS

Disseminated VZV is potentially life-threatening and occurs mostly in those with severe immunocompromise. Inadvertent administration of ZVL to immunocompromised individuals has occurred despite initial provider guidance and education. Multiple additional strategies to assist providers to identify contraindications have been implemented to prevent adverse outcomes.

Prevention of Herpes Zoster: A Focus on the Effectiveness and Safety of Herpes Zoster Vaccines

Infection with varicella zoster virus typically occurs in children and it can cause primary varicella infection or "chickenpox", or it can reactivate later in life and cause herpes zoster or "shingles". Herpes zoster mainly occurs in older adults, causing a reduction in activities of daily living, impacting quality of life, and may lead to serious complications, including chronic pain. Two vaccines are marketed to prevent herpes zoster: the live zoster vaccine and the non-live, recombinant zoster vaccine. The pre-licensure clinical trials show the efficacy of the live zoster vaccine to be between 50 and 70% and for the recombinant vaccine to be higher at 90 to 97%. Real-world effectiveness studies, with a follow-up of approximately 10 years, were reviewed in this article. These data corroborated the efficacy studies, with vaccine effectiveness being 46% and 85% for the live and recombinant vaccines, respectively. Safety data from the effectiveness studies show similar results to the clinical trials with mostly local injection-site reactions and mild systemic reactions seen with both vaccines, although in larger proportions with the recombinant vaccine. Rare adverse events, occurring less than 1% of the time, have been seen with both vaccine types and include disseminated herpes zoster with the live zoster vaccine and Guillain-Barré syndrome with the recombinant vaccine. The wider use of preventative measures with vaccines will reduce the herpes zoster burden of illness seen in older adults.

Characteristics and Comparison of Adverse Events of Coronavirus Disease 2019 Vaccines Reported to the United States Vaccine Adverse Event Reporting System Between 14 December 2020 and 8 October 2021

Background

This study assessed and compared the frequency and type of adverse events (AEs) of the Pfizer-BioNTech, Moderna, and Janssen coronavirus disease 2019 (COVID-19) vaccines reported in the Vaccine Adverse Event Reporting System (VAERS).

Methods

A retrospective analysis examined VAERS reports between 14 December 2020 and 8 October 2021 and focused on AE reports related to COVID-19 vaccines and AE outcomes [e.g., emergency room (ER) visits after being vaccinated, hospitalization, prolongation of existing hospitalization, life-threatening events, disability, birth defect, and death]. Reporting odds ratios (RORs) and Breslow-Day statistics were used to compare AE reporting between COVID-19 and non-COVID vaccines and between individual COVID-19 vaccines.

Results

A total of 604,157 AEs of COVID-19 vaccines were reported, including 43.51% for the Pfizer-BioNTech vaccine, 47.13% for the Moderna vaccine, and 9.12% for the Janssen COVID-19 vaccine. About 12.56% of patients visited ER after being vaccinated, 5.96% reported hospitalization, and 1.52% reported life-threatening events. Among the number of death cases (n = 7,674; mean age = 73), 2,025 patients (26.39%) had hypertension and 1,237 (16.12%) patients had cancer. RORs between COVID-19 vaccines and non-COVID vaccines identified increased ROR in ER visits, hospitalization, and life-threatening events. The results of the Breslow-Day statistics indicated heterogeneities between the disproportionality of reports across the four serious AE outcomes (i.e., ER visits, hospitalization, life-threatening events, and disability) between individual COVID-19 vaccines.

Conclusion

Most current VAERS reports showed that the most commonly reported AEs of COVID-19 vaccines were mild. Cases with a mortality outcome tended to occur in older adults with underneath conditions. Close ongoing surveillance in the safety of COVID-19 vaccines is critical and will inform the use of individual COVID-19 vaccines. Given the known limitations associated with the passive spontaneous reporting system, such as VAERS, our findings need to be further assessed and verified through longitudinal, large healthcare data systems.