This study intends to screen children under the age of 10 for respiratory pathogens, Streptococcus pneumoniae, and serotyping in three representative cities in Hainan province: Haikou, Wanning, and Baisha, in order to provide a foundation for the subsequent promotion of Streptococcus pneumoniae vaccines.

The purpose of this multi-center epidemiological study was to determine the carrier status of clinically diagnosed pneumonia, pathogen spectrum of clinically diagnosed pneumonia, serotype distribution, and drug resistance profile of Streptococcus pneumoniae in sick children from hospitals and healthy children from the community.

Inclusion Criteria:

• 1. Case group: patients from fever clinics and pediatric wards

Patients with at least one of the following will be clinically diagnosed with pneumonia and recommended for NP/OP, blood cultures, or induced sputum as clinically indicated (TB only or if performed routinely by the clinician), bronchoalveolar lavage fluid (BALF , according to clinical requirements), pleural effusion (according to clinical requirements), and chest X-ray examination:

1. Shortness of breath ( children <2 months, respiratory rate ≥60 breaths/min; children ≥2 months to <12 months, respiratory rate ≥50 breaths/min; children ≥12 months to < 60 months, respiratory rate ≥40 breaths/min; Children ≥ 60 months to < 120 months, respiratory rate > 24 breaths/minute )

2. Rales on lung auscultation

3. Respiratory symptoms and fever ( axillary temperature ≥ 37.5 ℃ or rectal temperature ≥ 38 ℃ )

   • 2. Control group The control group will be randomly selected from the community and frequency-matched 1:1 with the case group according to age group, sex and city.

Exclusion Criteria:

• 1. Hospitalized within the first 14 days, or discharged as a case group within the first 30 days, and lived outside the research center area ;
• 2. People who affect the research results: patients cannot keep samples or the amount of samples is not enough for testing;
• 3. Can't cooperate well;
• 4. The researcher judges that it is not suitable to be included in this study .

The prevalance of clinial diagnosed pneumonia and invasive diseases in Hainan Province will be mainly collected from the electronic medical record (EMR) database of selected hospitals and face-to-face questionnaire survey, in the fever clinics and pediatric wards of selected hospitals. A control group of healthy community children will be systematically sampled from residents from the same area as the cases and frequency-matched by age group.

After thesis defense the study may be published internationally to be available for the public.