What is the context? What is new? What is the impact?

Otitis media (OM) is a common disease of childhood and available pneumococcal conjugate vaccines (PCVs), with different compositions, could have different impact on OM reduction. This systematic literature review evaluated available data describing the efficacy, effectiveness, and impact of 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) and 13-valent PCV (PCV13) on OM outcomes. Statistically significant reductions in all-cause and complicated OM, tympanostomy tube placement and OM-related hospitalizations were consistently observed after the introduction of PHiD-CV and PCV13. Impact studies with data in children <2 years of age using PCV13 report 47–51% and PHiD-CV 34–43% reduction of all-cause OM (primary care, outpatient, ambulatory, emergency department visits) compared to periods before PCV introduction. When the impact of both vaccines is assessed in comparable settings, some studies suggest PHiD-CV may offer better protection against some OM outcomes. Well-designed, head-to-head comparisons are needed to better understand the differences and guide vaccination policies. What is the context? What is new? What is the impact?

Introduction: Pneumococcal diseases (including pneumonia, meningitis and sepsis) are among the leading vaccine-preventable causes of death in under-5-year-olds. Pneumococci are also one of the main bacterial pathogens associated with acute otitis media (AOM). Infant immunization programs with pneumococcal conjugate vaccines (PCVs) have led to stark reductions in pneumococcal disease rates. Areas covered: We summarized the development of the pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) and evidence of its protective effect in children, since its licensure one decade ago. We highlighted the most recent data from post-licensure studies on invasive pneumococcal disease (IPD), pneumonia and AOM and from health economic evaluations. We present results from a model estimating PHiD-CV’s impact on pneumococcal-related deaths. Expert opinion: Recent data from post-licensure studies confirm the previously demonstrated positive impact of PHiD-CV on IPD, pneumonia, AOM and AOM-related interventions (e.g., antibiotic use). Despite the success of infant PHiD-CV (and other PCV) programs, pneumococcal diseases still pose a substantial public health burden. Further reducing this burden will require improving access to currently available PCVs, increasing vaccination coverage and addressing the remaining burden due to non-vaccine serotypes. Future availability of lower-cost PCVs, PCVs with a broader serotype coverage and serotype-independent vaccines may contribute to this. Plain Language Summary What Is the Context? What Does This Review Highlight? What Is the Impact of This Review on Current Thinking?

Disease surveillance data are needed to monitor trends in disease activity, inform decision-making in public health and evaluate disease prevention/control measures. The Sistema Regional de Vacunas (SIREVA) supports laboratory-based surveillance of invasive pneumococcal disease (IPD) in Latin American countries, providing information on identification, distribution, and anti-microbial susceptibility of pneumococcal strains. We estimated the proportion of pneumococcal meningitis and sepsis/bacteremia cases captured by SIREVA, by comparing the number of SIREVA-reported isolates in Argentina, Brazil, Chile, Colombia, Ecuador and Mexico with the estimated expected number of cases based on regional estimates of disease incidence. In all six countries, the number of isolates reported by SIREVA was consistently lower than the number of cases expected, across all years with data available. The proportion of SIREVA-reported isolates was highest in Chile (43–83%) and lowest in Mexico (1.4–3.5%). Passive surveillance systems such as SIREVA are important tools for monitoring circulating strains that could be related to pneumococcal disease, but our results show that SIREVA is likely to underestimate pneumococcal disease incidence. This under-reporting will limit the precision of surveillance data in monitoring changes in the incidence of IPD after vaccine introduction, and this should be considered when assessing the impact of vaccination programs. What is the context? What is new? What is the impact?

Introduction Pertussis, a contagious respiratory disease, is underreported in adults. The study objective was to quantify underestimation of pertussis cases in adults aged ≥ 50 years in five Latin American countries (Argentina, Brazil, Chile, Mexico, Peru). Methods A previously published probabilistic model was adapted to adjust the number of pertussis cases reported to national surveillance systems by successive multiplication steps (proportion of pertussis cases seeking healthcare; proportion with a specimen collected; proportion sent for confirmatory testing; proportion positive for pertussis; proportion reported to passive surveillance). The proportions at each step were added in a random effects model to produce a pooled overall proportion, and a final multiplier was calculated as the simple inverse of this proportion. This multiplier was applied to the number of cases reported to surveillance to estimate the number of pertussis cases. Monte Carlo simulation with 10,000 iterations estimated median as well as upper and lower 90% values. Input data were obtained from surveillance systems and published sources. Results The estimated median underestimation factor for pertussis cases in adults ranged from 104 (90% limits 40, 451) in Chile to 114 (90% limits 39, 419) in Argentina. In all five countries, the largest estimated number of cases was in the group aged 50–59 years. The highest number per 100,000 population was in the group aged ≥ 90 years in most countries. The estimated median underestimation factor for pertussis hospitalizations was 2.3 (90% limits 1.8, 3.3) in Brazil and 2.4 (90% limits 1.8, 3.2) in Chile (data not available for other countries). Conclusion This analysis indicates that the number of pertussis cases in adults aged ≥ 50 years in five Latin American countries is approximately 100 times higher than the number captured in surveillance data. These results could support decision-making in the diagnosis, management, and prevention of pertussis disease in adults.