Long-term Impact of Pneumococcal Conjugate Vaccines on Invasive Disease and Pneumonia Hospitalizations in Indigenous and Non-Indigenous Australians

BACKGROUND

Universal pneumococcal conjugate vaccine (PCV) programs began in Indigenous Australian children in 2001 and all children in 2005, changing to 13-valent PCV (PCV13) in 2011. We used laboratory data for invasive pneumococcal disease (IPD) and coded hospitalizations for noninvasive pneumococcal community-acquired pneumonia (PnCAP) to evaluate long-term impact.

METHODS

Annual incidence (per 100 000 population) was calculated for age-specific total IPD, PCV13 non-7-valent PCV (PCV7) serotypes, and PnCAP by Indigenous status. Incidence in the pre-universal PCV7 (2002-2004), early PCV7 (2005-2007), pre-PCV13 (2008 to mid-2011), and post-PCV13 (mid-2011 to 2016) periods was used to calculate incidence rate ratios (IRRs).

RESULTS

In the total population, all-age incidence of IPD declined from 11.8 pre-PCV7 to 7.1 post-PCV13 (IRR, 0.61 [95% confidence interval {CI}, .59-.63]) but for PnCAP declined among ages <1 year (IRR, 0.34 [95% CI, .25-.45]) and 1-4 years (IRR, 0.50 [95% CI, .43-.57]) but increased significantly among age ≥5 years (IRRs, 1.08-1.14). In Indigenous people, baseline PCV13 non-PCV7 IPD incidence was 3-fold higher, amplified by a serotype 1 epidemic in 2011. By 2015-2016, although incidence of IPD and PnCAP in children aged <5 years decreased by 38%, neither decreased in people aged ≥5 years.

CONCLUSIONS

Fifteen years post-PCV and 5 years post-PCV13, direct and indirect impact on IPD and PnCAP differed by age and between Indigenous and non-Indigenous people, with potential implications for long-term PCV impact in comparable settings.Fifteen years after pneumococcal conjugate vaccine (PCV) introduction and 5 years post-PCV13, direct and indirect impact on invasive pneumococcal disease and pneumococcal community-acquired pneumonia differed by age and between Indigenous and non-Indigenous people, with potential implications for long-term PCV impact in comparable settings.

Effectiveness of Acellular Pertussis Vaccine in Older Adults: Nested Matched Case-control Study

Background

Despite recommendations that older adults receive acellular pertussis vaccines, data on direct effectiveness in adults aged over 50 years are sparse.

Methods

A case-control study nested within an adult cohort. Cases were identified from linked pertussis notifications and each matched to 3 controls on age, sex, and cohort recruitment date. Cases and controls were invited to complete a questionnaire, with verification of vaccination status by their primary care provider. Vaccine effectiveness (VE) was estimated by conditional logistic regression, with adjustment for reported contact with children and area of residence.

Results

Of 1112 notified cases in the cohort, we had complete data for 333 cases and 506 controls. Among 172 PCR-diagnosed cases (mean age, 61 years), 11.2% versus 19.5% of controls had provider-verified pertussis vaccination, on average, 3.2 years earlier. Adjusted VE against PCR-diagnosed pertussis was 52% (95% CI, 15–73%), nonsignificantly higher if vaccinated within 2 years (63%; −5–87%). Adjusted VE was similar in adults born before 1950, presumed primed by natural infection (51%; −8–77%) versus those born 1950 or later who may have received whole-cell pertussis vaccine (53%; −11–80%) (P-heterogeneity = 0.9). Among 156 cases identified by single-point serology, adjusted VE was −55% (−177–13%).

Conclusions

We found modest protection against PCR-confirmed pertussis among older adults (mean age, 61 years; range, 46–81 years) within 5 years after acellular vaccine. The most likely explanation for the markedly divergent VE estimate from cases identified by single-titer serology is misclassification arising from limited diagnostic specificity in our setting.

Leakage Currents in CVD (Ba,Sr)TiO3 Thin Films

We have analyzed the leakage behavior of polycrystalline MOCVD (Ba,Sr)TiO3 thin films as a function of both temperature and field. Of the possible mechanisms, thermionic (Schottky) emission gives a self-consistent description of the temperature and field dependencies of the true leakage current for fields in the range of 240–970 kV/cm, and yields realistic barrier heights of 1.2 eV for Pt as the cathode material. For film thicknesses of interest for use in DRAMs, the capacitance-voltage characteristics are explained via Landau-Ginzburg-Devonshire theory. Preliminary resistance degradation studies are also discussed.