<p><strong>OBJECTIVES: </strong>To determine if serum procalcitonin, an indicator of bacterial etiology in pneumonia in all ages and a predictor of severe pneumonia in adults, is associated with disease severity in children with community-acquired pneumonia.</p>

<p><strong>METHODS: </strong>We prospectively enrolled children 2 months to &lt;18 years with clinical and radiographic pneumonia at 2 children's hospitals (2014-2019). Procalcitonin samples were obtained at presentation. An ordinal outcome scale of pneumonia severity was defined: very severe (intubation, shock, or death), severe (intensive care admission without very severe features and/or high-flow nasal cannula), moderate (hospitalization without severe or very severe features), and mild (discharge). Hospital length of stay (LOS) was also examined. Ordinal logistic regression was used to model associations between procalcitonin and outcomes. We estimated adjusted odds ratios (aORs) for a variety of cut points of procalcitonin ranging from 0.25 to 3.5 ng/mL.</p>

<p><strong>RESULTS: </strong>The study included 488 children with pneumonia; 30 (6%) were classified as very severe, 106 (22%) as severe, 327 (67%) as moderate, and 25 (5%) as mild. Median procalcitonin in the very severe group was 5.06 (interquartile range [IQR] 0.90-16.83), 0.38 (IQR 0.11-2.11) in the severe group, 0.29 (IQR 0.09-1.90) in the moderate group, and 0.21 (IQR 0.12-1.2) in the mild group. Increasing procalcitonin was associated with increasing severity (range of aORs: 1.03-1.25) and increased LOS (range of aORs: 1.04-1.36). All comparisons were statistically significant.</p>

<p><strong>CONCLUSIONS: </strong>Higher procalcitonin was associated with increased severity and LOS. Procalcitonin may be useful in helping clinicians evaluate pneumonia severity.</p>

<p>Additional strategies are needed to protect children from vaccine-preventable diseases. In particular, very young infants, as well as children who are immunocompromised, are at especially high risk for developing the serious consequences of vaccine-preventable diseases and cannot be immunized completely. There is some evidence that children who become infected with these diseases are exposed to pathogens through household contacts, particularly from parents or other close family contacts. Such infections likely are attributable to adults who are not fully protected from these diseases, either because their immunity to vaccine-preventable diseases has waned over time or because they have not received a vaccine. There are many challenges that have added to low adult immunization rates in the United States. One option to increase immunization coverage for parents and close family contacts of infants and vulnerable children is to provide alternative locations for these adults to be immunized, such as the pediatric office setting. Ideally, adults should receive immunizations in their medical homes; however, to provide greater protection to these adults and reduce the exposure of children to pathogens, immunizing parents or other adult family contacts in the pediatric office setting could increase immunization coverage for this population to protect themselves as well as children to whom they provide care.</p>