Multiple myeloma patients often get serious infections that can be deadly. A British study looked at newly diagnosed patients and found that bacterial infections were the main cause of death in the first 60 days, mostly from pneumonia (66%) and blood poisoning (23%). The most common bacteria causing these infections were pneumococcus, staph, and E. coli.

Medical experts recommend that multiple myeloma patients get pneumonia vaccines. However, some studies show these vaccines don't work well in these patients, raising questions about whether they're really helpful. It's also unclear if patients need one shot or multiple shots like other high-risk patients.

This study at National Taiwan University Hospital will randomly give multiple myeloma patients either one or two doses of the 13-valent pneumonia vaccine. Researchers will check if the vaccine is safe and if it helps the immune system fight infections, while trying to figure out what makes the vaccine work better in some patients than others.

Infection has always been a common and potentially life-threatening problem for multiple myeloma patients. A British study on newly diagnosed multiple myeloma patients investigated the causes of death within 60 days of enrollment and found that bacterial infection was the most common cause of death, followed by kidney failure, myocardial infarction, or stroke. Among patients who died from bacterial infections, 66% died from pneumonia, 23% from sepsis, and 11% from other infections. Among bacterial infection patients with culture results, Streptococcus pneumoniae was the most common pathogen, followed by Staphylococcus aureus and Escherichia coli.

The International Myeloma Working Group recommends that multiple myeloma patients receive pneumococcal vaccination. Some research findings have shown that pneumococcal vaccination in multiple myeloma patients is ineffective or very limited in effectiveness, questioning the recommendation for routine pneumococcal vaccination. Furthermore, it remains unknown whether multiple doses of vaccine are needed, as in hematopoietic stem cell transplant patients.

Therefore, for multiple myeloma patients at National Taiwan University Hospital, this study aims to randomly assign patients to receive either one or two doses of 13-valent pneumococcal conjugate vaccine, evaluate its safety and immune response generation, and identify factors related to vaccine efficacy.

Inclusion Criteria:

• Patients with multiple myeloma
• Stable clinical condition to have vaccination at outpatient clinic

Exclusion Criteria:

• Those who have received pneumococcal vaccine within the past five years
• Unable to communicate verbally with the subject
• Subject has an active infection
• Pregnant women