Expert Q&A: Severe Pneumococcal Infection May Signal Hidden Blood Cancer or Immunodeficiency

A severe pneumococcal infection may be the first clinical sign of an undiagnosed B-cell malignancy or antibody deficiency in adults, according to a prospective, multicenter study published in Scientific Reports. Among 156 adults hospitalized with invasive pneumococcal disease (IPD) in Sweden, monoclonal immunoglobulin (M protein) was detected in 27% of patients during acute infection compared with 4.7% of matched controls. Follow-up evaluation led to 7 new hematologic cancer diagnoses and 12 diagnoses of monoclonal gammopathy of undetermined significance (MGUS), and 7 patients started immunoglobulin replacement therapy.^1,2

Because serum protein and immunoglobulin testing is not routinely performed after a single IPD episode, these underlying conditions often go unrecognized, according to the investigators. This gap may hold particular relevance for pharmacists, who frequently encounter patients after a pneumonia hospitalization and play a central role in adult pneumococcal immunization.¹

Expert Insights

In an interview with Pharmacy Times, Tor Härnqvist, MD, an infectious disease physician at NU Hospital Group, doctoral student at the University of Gothenburg in Sweden, and co–lead author of the study, discussed what should prompt concern for an underlying immune disorder after IPD, how shifting serotype distribution should inform vaccine selection for older and immunocompromised adults, and how pharmacists can support patients who begin immunoglobulin replacement therapy.

Pharmacy Times: Pharmacists often see patients after a hospitalization for pneumonia. What should prompt concern that a severe pneumococcal infection may point to an underlying blood cancer or immunodeficiency, and how can pharmacists help make sure follow-up testing isn't missed?

Tor Härnqvist, MD: Our findings suggest that invasive pneumococcal disease can, in some adult patients, reveal a previously unrecognized underlying immunodeficiency or monoclonal gammopathy. Invasive pneumococcal disease may therefore warrant assessment of M-protein and immunoglobulin levels. Pharmacists can contribute by reviewing whether appropriate follow-up has been arranged and encouraging patients to discuss further evaluation with their treating physician when indicated. Further studies are needed to determine which patients would benefit most from immune assessment.

Pharmacy Times: Your research shows that serotypes covered by the childhood vaccine have been largely replaced by others. What does that mean for pneumococcal vaccine selection in older adults and immunocompromised patients, and what should pharmacists consider when recommending a vaccine?

Härnqvist: Older adults and individuals with immunocompromising conditions should be protected against pneumococcal disease according to current vaccination recommendations. At present, two higher-valency conjugate vaccines, PCV20 and PCV21, are available, covering 20 and 21 pneumococcal serotypes, respectively.

Our results, previously published in BMC Infectious Diseases (doi: 10.1186/s12879-021-06430-y), illustrate that pneumococcal serotype distribution changes over time. When discussing vaccination, pharmacists should therefore follow current national recommendations and consider the patient's age, underlying medical conditions, previous pneumococcal vaccinations, and the serotype coverage of currently available vaccines.

Pharmacy Times: Seven patients with newly identified immunodeficiency started preventive treatment against new infections. What did that treatment involve, and what role can pharmacists play in supporting these patients over time?

Härnqvist: The patients referred to in our study had hypogammaglobulinemia and were started on immunoglobulin replacement therapy. The aim of this treatment is to reduce susceptibility to recurrent and potentially severe infections. Pharmacists can play an important role in the long-term care of these patients by supporting adherence to prescribed therapy, reviewing medications and vaccination status, and helping patients understand the importance of promptly seeking medical attention for signs of infection.

REFERENCES

1. Härnqvist T, Bergman K, Mellgren Å, et al. Invasive pneumococcal disease unmasks monoclonal immunoglobulins and antibody deficiencies: a multicenter prospective study in adults. Sci Rep. 2026;16(1):23203. doi:10.1038/s41598-026-61992-8

2. Ferruggia K. Invasive pneumococcal disease may unmask undiagnosed blood cancers, antibody deficiencies in adults. Pharmacy Times. October 1, 2026. Accessed October 5, 2026. https://www.pharmacytimes.com/view/invasive-pneumococcal-disease-may-unmask-undiagnosed-blood-cancers-antibody-deficiencies-in-adults