Pasiarski M, Sosnowska-Pasiarska B, Grywalska E, et al. - Researchers compared 22 treatment-naive patients with monoclonal gammopathy of undetermined significance (MGUS) vs 15 healthy age- and sex-matched volunteers in terms of the immune response to the 13-valent pneumococcal conjugate vaccine (PCV13). They found that it was safe to administer PCV13 in MGUS patients, and this vaccination offered effective protection against the development of S. pneumoniae infection in these patients. Vaccinating the unvaccinated people immediately after diagnosis was recommended. By preventing the development of serious infectious complications, it could contribute to extending the time to progression and transformation into more aggressive diseases. MGUS patients with a lower level of M protein exhibited a greater efficacy of PCV13 vaccination. In MGUS patients, the possible utility of serum M protein concentration was suggested as a predictor of the efficacy of vaccination.