Effectiveness of quadrivalent influenza vaccination in the first year of a funded childhood program in Queensland, Australia, 2018

Trends in effectiveness of inactivated influenza vaccine in children by age groups in seven seasons immediately before the COVID-19 era

“…Similar to our report, the VE among children aged 1–2 years was higher (63%) than the VE among children aged 2–5 years (45%–57%) in a prospective, non-randomized, observational study [21] . In contrast, according to a recent report in Australia, the adjusted VE analyzed by a matched case-control study increased with age among children 6 months to 4 years [22] . However, it is difficult to compare the VE with the previously published data because we could not exclude the effect of infection history or previous immunization, maternal immunization during pregnancy, dose-effect (once or twice), and difference in analyzed season and methodology.…”

“…We suppose that some children do not receive the vaccine twice because the cost (approximately $30–40 per dose) is not covered by national health insurance or the national government, because parents/guardians do not have time to take their children to the clinic, or because parents/guardians forget to arrange the second vaccination. Vaccine dose (once or twice) may influence the VE among young children [22] , [25] , [26] . However, no significant difference was observed in the present overall age-adjusted analysis when once or twice vaccine doses were compared ( Table 2 , Table 3 , Table 4 ).…”

“…Similarly, another report showed that the adjusted VE against any influenza was 51% (95% CI 44–57) and 41% (95% CI 25–54) among fully and partially vaccinated children aged 6 months to 8 years, respectively [26] . We speculate that the VE related to vaccine dose depends on many factors, including history of immunization and influenza infection [22] , seasons, and vaccine mismatch. Thus, the two-dose regimen can be recommended, especially for younger children.…”

Evidence of varicella zoster virus (VZV) reactivation in children with arterial ischemic stroke: Results of the VIPS II Study

“…33 Australia started a single-dose vaccination program in 2005, and Canadian provinces did the same between 2000 and 2007. 34, 35 In the VIPS II cohort, the majority of parents reported prior vaccination (prior chicken pox in only three), and baseline IgG serologies supported prior VZV exposure in 97% of cases. The time interval from vaccination (initial VZV exposure) to stroke was generally prolonged—a median of six years—much longer than the historic time interval (weeks to months) between chicken pox and stroke.…”