Critically ill adults admitted to intensive care units (ICUs) are often older and have multiple chronic conditions that increase risk for invasive infections. However, data on prior pneumococcal vaccination status in the ICU population are limited. The investigators aimed to measure pneumococcal vaccination coverage among ICU patients eligible under the Japanese routine vaccination program and to identify factors associated with reported pneumococcal vaccination.
This was a cross-sectional study conducted in an ICU at a tertiary care hospital in Japan. The study period spanned admissions from May 15, 2023 to January 4, 2024. Eligibility for pneumococcal vaccination was determined with reference to the Japanese routine vaccination program in effect during the study period. The study used a structured questionnaire administered to patients or family members at ICU admission to capture vaccination histories for pneumococcal vaccine as well as for influenza and coronavirus disease 2019 (COVID-19) vaccines. Multivariable logistic regression analysis was performed among eligible patients with known pneumococcal vaccination status to evaluate factors independently associated with reported pneumococcal vaccination.
A total of 982 patients were admitted during the study interval. Of these, 757 patients (77.1%) met the predefined eligibility criteria for pneumococcal vaccination according to the referenced Japanese routine vaccination program. Thirty-two eligible patients did not respond to the vaccination questionnaire and were excluded from the analysis of vaccination status, leaving 725 eligible patients with vaccination-status data.
Vaccination status for pneumococcal, influenza, and COVID-19 vaccines was obtained via the structured questionnaire given to the patient or, when patients could not respond, to family members during ICU admission. The source reports the method of ascertainment and that eligibility was defined by the national routine program, but additional operational details such as exact eligibility age thresholds, timing requirements, or verification against medical records were not reported in the abstract.
Among the 725 eligible patients with assessed vaccination status, 124 patients (17.1%) reported having received a pneumococcal vaccine. A majority, 371 patients (51.2%), reported no pneumococcal vaccination. A substantial proportion—230 patients (31.7%)—reported an unknown pneumococcal vaccination status. These findings indicate that a minority of eligible ICU patients reported prior pneumococcal vaccination and that nearly one-third had no clear record or recollection of their pneumococcal vaccine history.
In multivariable logistic regression analysis limited to eligible patients with known pneumococcal vaccination status, prior influenza vaccination was the only factor independently associated with reported pneumococcal vaccination. The reported odds ratio was 31.8 with a 95% confidence interval of 4.3 to 236.7 and a p value < .001. No other independent associations were reported in the abstract.
The study highlights two key issues in the ICU population: low reported uptake of pneumococcal vaccine among those eligible and a high proportion of patients with unknown pneumococcal vaccination status. The strong association between influenza vaccination and reported pneumococcal vaccination suggests clustering of preventive vaccine uptake in some patients but does not establish causation. Clinically, these findings point to the need for more reliable vaccination records accessible at or before ICU admission and for routine assessment of vaccine eligibility and history in critically ill patients. Improving documentation and verification could allow for targeted vaccination interventions or catch-up programs when appropriate.
The source material is an abstract and provides a limited amount of methodological detail. Specific limitations that can be inferred or that were noted include: reliance on patient or family recall for vaccination status, the exclusion of 32 non-responders which reduced the evaluable sample, and the single-center design at a tertiary care hospital in Japan which may limit generalizability. The abstract does not report additional variables examined, definitions applied for eligibility beyond referencing the national routine program, nor details on how nonresponse or unknown status were handled beyond reporting counts.
In this single-center cross-sectional study of ICU admissions in Japan, most ICU patients were eligible for pneumococcal vaccination, but only 17.1% of eligible patients reported prior pneumococcal vaccination and 31.7% reported unknown status. Prior influenza vaccination was strongly associated with reported pneumococcal vaccination in multivariable analysis. The findings support the need for improved vaccination records and routine opportunities to assess and document vaccination eligibility and history among critically ill patients. Further detail on methods and broader multicenter data were not provided in the source abstract.