Vaccination and Infection Risk

Introduction to Vaccination Risks

• Vaccination does not guarantee protection against fulminant pneumococcal disease, which has a case-fatality rate of 50-80% 1
• Asplenic patients remain at lifelong risk for overwhelming post-splenectomy infection (OPSI) 1

Hematologic Disorders and Surgical Risks

• Hematologic disorders, such as idiopathic thrombocytopenic purpura (ITP), myeloid dysplasia, and myelofibrosis, can increase the risk of surgical complications, with varying degrees of morbidity and mortality, as noted by the American Society of Hematology and the American College of Surgeons 2, 3
• ITP has an approximately 10% surgical complication rate, even with less-invasive laparoscopic methods, with high response rates (85% initial response), according to the American Society of Hematology 2
• Myeloid dysplasia/myelofibrosis has the highest postoperative morbidity after splenectomy, with a perioperative mortality of 5-10% and complications in approximately 50% of patients, as reported by the American College of Surgeons 3
• The American College of Surgeons recommends careful patient selection for splenectomy in patients with myeloid dysplasia/myelofibrosis due to high morbidity rates, with a strength of evidence based on clinical guidelines 3

Vaccination Recommendations

• The National Comprehensive Cancer Network, American College of Physicians, and Centers for Disease Control and Prevention recommend pneumococcal, meningococcal, Haemophilus influenzae type b, and annual influenza vaccines for asplenic patients to prevent potentially fatal infections from encapsulated bacteria 4, 5, 6
• The recommended pneumococcal vaccination schedule is PCV13 (conjugate vaccine) followed by PPSV23 (polysaccharide vaccine) with an interval of at least 8 weeks, and a booster dose of PPSV23 after 5 years, according to the Centers for Disease Control and Prevention 6
• The following table summarizes vaccine recommendations:

Infection Prevention and Management

• Patients who have undergone splenectomy are at risk of infections and should take preventive measures, including keeping amoxicillin at home and wearing a Medic-Alert bracelet, as suggested by the British Medical Journal 7
• At least 2 years of prophylactic antibiotics are recommended after splenectomy, with lifelong prophylaxis considered, especially for high-risk patients, such as immunocompromised individuals and children under 5 years, according to the British Medical Journal and the World Journal of Emergency Surgery 8, 7
• Patients should be informed about the lifelong risk of severe infections and educated about the importance of seeking immediate medical attention for fever >38°C (101°F), and keep a supply of amoxicillin at home to be used immediately if symptoms of infection develop, according to the World Journal of Emergency Surgery and the British Medical Journal 8, 7
• Special considerations are required for immunocompromised individuals, including those with hematologic malignancies, who require lifelong prophylaxis and close monitoring, and children under 5 years require special consideration for antibiotic prophylaxis and vaccination 8, 7
• Animal bites require a 5-day course of Amoxicillin/Clavulanic acid, or co-amoxiclav (erythromycin for allergic patients) due to the risk of C. canimorsus infection, and tick bites pose a risk of babesiosis, especially for patients in contact with animals, and travel to endemic areas for malaria, histoplasmosis, or babesiosis requires special precautions, according to the World Journal of Emergency Surgery and the British Medical Journal 8, 7

Management of Specific Conditions

• Platelet count should be kept below 400×10^9/L to prevent postoperative extreme thrombocytosis in myelofibrosis patients, with a strength of evidence based on clinical guidelines 3
• Patients with myeloid dysplasia/myelofibrosis are at increased risk of infections due to functional hyposplenism, with a moderate risk of complications, and a higher risk of overwhelming post-splenectomy infection (OPSI) compared to other hematologic conditions 7