Pfizer Begins Testing COVID-19 Booster Shot With Pneumococcal Vaccine.<br />The drugmaker began administering its first coronavirus booster shots on May 24.<br />Pfizer is conducting a trial to see if it is safe to administer a third dose of the vaccine... .<br />... in tandem with a <br />pneumococcal vaccine candidate. .<br />Pneumococcal vaccines help <br />to prevent pneumonia.<br />600 adults over the age of 65 <br />will participate in the study.<br />They will follow up with <br />Pfizer six months later
