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Learning how the 20-valent pneumococcal vaccine works against pneumonia

A Phase 4 Study Using a Test-Negative Design to Evaluate the Effectiveness of a 20-valent Pneumococcal Conjugate Vaccine Against Vaccine-type Radiologically-confirmed Community-acquired Pneumonia in Adults >/= 65 Years of Age

Observational Pfizer · NCT05452941

This study is trying to see if the 20-valent pneumococcal vaccine can help prevent pneumonia in people aged 65 and older who are hospitalized with suspected pneumonia.

Quick facts

Study typeObservational
Enrollment12500 (estimated)
Ages65 Years and up
SexAll
SponsorPfizer Industry-sponsored
Locations54 sites (El Centro, California and 53 other locations)
Trial IDNCT05452941 on ClinicalTrials.gov

What this trial studies

This observational study aims to evaluate the effectiveness of the 20-valent pneumococcal conjugate vaccine (20vPnC) in preventing radiologically-confirmed community-acquired pneumonia (CAP) caused by specific serotypes of Streptococcus pneumoniae. Participants aged 65 and older who are hospitalized with suspected CAP will provide demographic and medical history information, along with a urine sample for testing. The study will compare the incidence of pneumonia caused by vaccine serotypes in vaccinated individuals versus those who are unvaccinated. The primary objective is to identify cases of pneumonia linked to the additional serotypes included in the 20vPnC vaccine.

Who should consider this trial

Good fit: Ideal candidates for this study are adults aged 65 and older who are hospitalized with suspected community-acquired pneumonia.

Not a fit: Patients who are younger than 65 or those without a confirmed diagnosis of pneumonia may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide valuable insights into the effectiveness of the 20vPnC vaccine in preventing pneumonia in older adults.

How similar studies have performed: Other studies have shown promising results with pneumococcal vaccines, but this specific observational approach to assess the 20vPnC vaccine's effectiveness is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Male or female participants ≥65 years of age.
2. Hospitalized participant with physician clinical suspicion of CAP with the presence of ≥2 of the following 10 clinical signs or symptoms:

   * fever (oral temperature \>38.0°C/100.4°F or tympanic temperature \>38.5°C/101.2°F),
   * hypothermia (\<35.5°C/95.9°F measured by a healthcare provider)
   * chills or rigors,
   * pleuritic chest pain,
   * new or worsening cough,
   * sputum production,
   * dyspnea (shortness of breath),
   * tachypnea (respiratory rate \>20/min),
   * malaise, or
   * abnormal auscultatory findings suggestive of pneumonia (rales or evidence of pulmonary consolidation including dullness on percussion, bronchial breath sounds, or egophony).
3. Has a radiographic finding that is consistent with pneumonia (e.g., pleural effusion, increased pulmonary density due to infection, the presence of alveolar infiltrates \[multi-lobar, lobar, or segmental\] containing air bronchograms).
4. Capable of giving signed informed consent

Exclusion Criteria:

1. Any participant who develops signs and symptoms of pneumonia after being hospitalized for ≥48 hours (either at the study site, another transferring hospital, or a combination of these).
2. Received any pneumococcal vaccine ≤30 days prior to enrollment.
3. Unable to provide urine specimen (e.g. anuric).
4. Previous enrollment in the study within the past 30 days.

Where this trial is running

El Centro, California and 53 other locations

+4 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Pneumonia
Last reviewed 2026-06-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.