THE CHALLENGES OF EVALUATING THE BURDEN OF PNEUMOCOCCAL PNEUMONIA

The Pfizer symposium “Revising the paradigm: the importance of adult vaccination against respiratory diseases” at ECCMID2021 discussed the prevention of pneumococcal disease in adults. The presentation “Assessing the burden of pneumococcal pneumonia in adults” by Antoni Torres highlighted current challenges in diagnosing and preventing pneumococcal pneumonia in the adult population.

Pneumococcal pneumonia represents the majority of pneumococcal disease in adults. However, it is not easy to estimate the disease burden due to diagnostic challenges. It has been estimated that only one out of four cases become invasive, and non-invasive cases are difficult to diagnose if the blood culture is negative (Said et al., 2013).

It is difficult to estimate the prevalence of pneumococcal community acquired pneumonia (CAP). Traditional methods of testing often fail to identify the causative respiratory pathogens in cases of CAP. Urinary antigen testing methods allow for improved microbiological diagnosis. Using these methods, the disease burden could prove higher than previously thought.

S. pneumoniae is the most common cause of hospitalized CAP. Pneumococcus is a significant causative pathogen of CAP, and in a study conducted in the Spanish adult population S. pneumoniae was identified to be the most frequent cause of hospitalized CAP (Said et al., 2013; Torres at al., 2021).

Serotype-specific testing methods give a wider perspective on disease burden. Knowledge of the specific serotypes most contributing to disease allows for informed decision-making in CAP management. However, traditional testing methods are often unspecific, and do not differentiate between serotypes.

Vaccine serotype coverage needs to be followed. A study conducted in Spain found that between 2011 and 2018, the serotype-specific burden of CAP has shifted, possibly due to effective vaccination campaigns in children (Torres at al., 2021). The study showed that between 2016 and 2018 the most commonly identified serotypes were 3 and 8.

There is reason to consider adult vaccination. Torres et al. (2021) concluded that pediatric vaccine coverage may nevertheless be insufficient in protecting the adult population, and direct immunization of adults could help prevent adult CAP.
 

ECCMID 2021 References: 

Assessing the burden of pneumococcal pneumonia in adults. Antoni Torres (Barcelona, Spain). Presented online at ECCMID 2021 on 9 July 2021. 

Additional references:

Said, M., Johnson, H., Nonyane, B., Deloria-Knoll, M., & O′Brien, K. (2013). Estimating the Burden of Pneumococcal Pneumonia among Adults: A Systematic Review and Meta-Analysis of Diagnostic Techniques. Plos ONE, 8(4), e60273. doi: 10.1371/journal.pone.0060273

Torres, A., Menéndez, R., España, P., Fernández-Villar, J., Marimón, J., & Cilloniz, C. et al. (2021). The Evolution and Distribution of Pneumococcal Serotypes in Adults Hospitalized With Community-Acquired Pneumonia in Spain Using a Serotype-Specific Urinary Antigen Detection Test: The CAPA Study, 2011–2018. Clinical Infectious Diseases. doi: 10.1093/cid/ciab307

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