We read with great interest the letter to the Editor1 contributed by Mascarós et al. on behalf the Neumoexpertos en Prevención group, which is supported by the Instituto de Investigación Sanitaria de Santiago, in collaboration with Pfizer (http://neumoexpertos.org/conflicto-de-intereses). These authors question the lack of a recommendation for anti-pneumococcal vaccination in asthma patients in the latest edition of the Spanish Guidelines for the Management of Asthma (GEMA 4.0).2 Their arguments hinge on recent consensus documents from experts recommending this intervention, and new studies that have shown its efficacy.3,4

Evidence-based clinical practice guidelines (CPG) propose recommendations when the scientific proof is available to support them. Unfortunately, in the case of the pneumococcal vaccine, the evidence is weak (or non-existent). Accordingly, it is not recommended by either the GEMA 4.0 or the most prestigious international guidelines, such as the Global Initiative for Asthma (GINA) or the British Thoracic Society (BTS). Of the 2 publications which Mascarós et al. claim provide new evidence for the efficacy of the vaccine, the study by Okapuu et al.3 is a simple arithmetic exercise based on a database crossover involving the calculation of a hypothetical number of cases needed to be treated (NNT), rather than the analysis of data gathered in a prospective clinical trial. The study by Bonten et al. (CAPITA study)4 provides evidence for the indication of the PVC13 pneumococcal vaccine in patients over 65 years of age, but cannot be used as an argument to support its indication in the asthma population, since no specific subanalysis was performed in this group. Moreover, recommendations from expert groups published in recent consensus documents that lack the support of robust studies provide only low-level (or non-existent) evidence – the type of evidence which, in general, is avoided in CPGs.

Nevertheless, as the asthma population has a greater risk of presenting invasive pneumococcal disease,5 and pneumococcal vaccination is effective in preventing this infection in the general population, even if the evidence for its indication in the asthma population is weak (or non-existent), the Spanish National Health System (http://www.msssi.gob.es) has recently recommended its use in patients with severe asthma. We, the signatories of GEMA 4.0 (mostly clinical physicians), consider that pneumococcal vaccination in patients with severe asthma is probably beneficial, but as writers of evidence-based CPGs, we are obliged to limit our recommendation until rigorous proof of this indication is available. In view of these findings, it seems appropriate at the present time to go no further in recommending pneumococcal vaccination in the asthmatic population. The GEMA signatories will include this recommendation in the future, if new, robust evidence supporting this approach should emerge.