Phase Ⅰa Clinical Trial of a Pneumococcal Vaccine

Inclusion Criteria: * Healthy volunteers aged 18 to 49 years old; * Willing to provide proof of identity; * Able to understand and sign the informed consent; * Able and willing comply with the requirements of the protocol Exclusion Criteria: * Hypertensive volunteers with uncontrollable medications (on-site measurement: systolic blood pressure \> 140 mmHg, diastolic blood pressure \> 90 mmHg); * Abnormal changes of laboratory measures (with clinical significance); * Woman is pregnant and lactating (by urine pregnancy test) * Suffered from pneumonia in the past three years; * Invasive diseases caused by Streptococcus pneumoniae (such as meningitis, bacteremia, pericarditis, peritonitis, etc.) in the past three years; * Allergic person; * Any prior administration of blood products in last 3 month; * Any prior administration of other research medicines in last 1 month; * Plans to participate in or is participating in any other drug clinical study; * Any prior administration of attenuated live vaccine in last 14 days; * Any prior administration of subunit or inactivated vaccines in last 7 days; * Had fever before vaccination, volunteers with temperature \>37.0℃ on axillary setting; * According to the investigator's judgment, the volunteers have any otherfactors that make them unfit to participate in the clinical trial