Influenza and Pneumococcal Immunization in Diabetes

RATIONALE FOR IMMUNIZATION

The rationale for the use of influenza and pneumococcal vaccine in patients with diabetes is reviewed in the American Diabetes Association technical review “Use of Influenza and Pneumococcal Vaccine in People with Diabetes” (1) and can be summarized as follows:

• Patients with diabetes may have abnormalities in immune function and presumed increased morbidity and mortality from infection.

• Epidemiological studies support the fact that patients with diabetes (in particular those with end organ complications of cardiac and renal disease) are at high risk for complications, hospitalization, and death from influenza and pneumococcal disease.

• There is sufficient evidence that people with diabetes generally have appropriate humoral immune responses to vaccination.

• Subgroup analysis of patients with diabetes reported in clinical narrative and case-control studies support the fact that vaccination against influenza has been effective in reducing hospital admissions during influenza epidemics.

• Although the question of the efficacy of pneumococcal vaccination in preventing nonbacteremic disease remains unresolved, many studies have shown that the vaccine is effective in reducing life-threatening bacteremic disease.

• Immunization against influenza and pneumococcal disease is an important part of preventive services for many chronic diseases such as diabetes.

According to the Advisory Committee on Immunization Practices (ACIP), the American College of Physicians, the American Academy of Pediatrics, and the American Academy of Family Physicians, vaccinating individuals at high risk before influenza season each year is the most effective measure for reducing the impact of influenza (2). The effective implementation of immunization can reduce the cost of human suffering and health care expenditures in people with diabetes.

The recommendations that follow are based in large part on observational studies with high potential for bias. The narrative review (1) supports expert opinion that immunization intervention is low risk, is low cost, and may have a moderate to substantial impact on the care of people with diabetes.

INFLUENZA VACCINATION

Consistent with the recommendations of the ACIP, the influenza vaccine should be recommended for patients with diabetes, age ≥6 months, beginning each September (2). It is strongly suggested that specific systematic intervention strategies be considered for patients with diabetes who are >64 years of age, residents of nursing homes or other chronic care facilities, require regular medical follow-up or hospitalization, or have additional secondary chronic disorders of the cardiopulmonary system. Intramuscular dosage and type of influenza vaccine (split or whole virus) vary based on the patient’s age (2).

Each year, a trivalent vaccine is constituted with strains of influenza A and B, which are most likely to circulate in the U.S. during the winter. Because the vaccine consists of egg-grown viruses, it should not be administered to individuals known to have anaphylactic hypersensitivity to chicken eggs or additional components of the influenza vaccine. Because immunity from influenza vaccination declines in the year after vaccination, yearly vaccination is recommended. Although antibody responses to repeat immunization have been reported to be greater in some people with diabetes, repeated immunization within the same season is not recommended (3). The ACIP does recommend two doses of influenza vaccine administered at least 1 month apart (the last administered before December) for children <9 years of age who have never been vaccinated (2).

Because infection with influenza virus can be transmitted from person to person, vaccination of health care workers and family of patients with diabetes may be justified. Influenza is a universal illness occurring throughout the year in the tropics and primarily from April to September in the Southern Hemisphere (2). Patients traveling to these areas should consider influenza vaccination before travel.

The influenza vaccine contains only noninfectious viruses and cannot cause influenza or other respiratory disease. The side effect most frequently experienced from vaccination is mild soreness at the vaccination site. In individuals with chicken egg allergy, immediate allergic reactions have been reported. In these patients, chemoprophylaxis with amantadine/rimantadine or immunization using a protocol as reported by Murphy and Strunk (4) should be considered. A recent study reported a slight increased risk of Guillain-Barré syndrome in the 6 weeks after influenza vaccination during the 1992–1993 and 1993–1994 flu seasons (5). For this reason, it is recommended not to administer the influenza vaccine to individuals known to have developed Guillain-Barré syndrome within 6 weeks of a previous influenza vaccination.

PNEUMOCOCCAL IMMUNIZATION

The current pneumococcal vaccine includes 23 purified capsular polysaccharide antigens representing 85–90% of the serotypes of Streptococcus pneumoniae that cause invasive pneumococcal infections among children and adults in the U.S. (6). People with diabetes are susceptible to pneumococcal infection and are at increased risk for the morbidity and mortality of bacteremia from this organism (1). Additional risk is associated with being age ≥65 years and having chronic cardiovascular, pulmonary, and renal disease.

According to the ACIP, pneumococcal vaccination is indicated to reduce invasive disease from pneumococcus in people with diabetes (6). Special efforts in implementation strategies for immunization should include the same target groups as for influenza. Additional emphasis has been suggested for Native American groups who have a high incidence of diabetes and invasive pneumococcal disease (7,8). There is insufficient evidence to support revaccination of people with diabetes unless other special circumstances exist.

A one-time revaccination is recommended for individuals >64 years of age previously immunized when they were <65 years of age if the vaccine was administered more than 5 years ago. Other indications for repeat vaccination potentially relevant to patients with diabetes include nephrotic syndrome, chronic renal disease, and other immunocompromised states, such as post-organ transplantation (6).

Approximately one-third to one-half of individuals receiving pneumococcal vaccine develop mild local side effects similar to influenza (lasting <48 h). Severe local or systemic reactions are rare, and neurologic syndromes such as Guillian-Barré syndrome have not been causally associated with pneumococcal vaccine administration (6). Pneumococcal vaccine may be administered with other vaccines (by a separate injection in another anatomic site) without an increase in side effects or decrease in efficacy.

CONCLUSIONS

Influenza and pneumoccocal immunization in patients with diabetes has the potential for significant reduction in morbidity and mortality related to influenza and pneumoccocal disease. Effective immunization strategies will require implementation strategies that are multidimensional and target the patient, provider, support staff/family/friends, and health system. The goal should be to immunize all patients with diabetes, particularly those with complicating factors such as cardiac or renal disease or those who are or have been recently hospitalized. The Healthy People 2010 public health goals are to administer the influenza vaccine to 90% of diabetic adults >65 years and 60% of diabetic adults <65 by the year 2010. Targeted educational interventions using immunization opportunities and staff empowerment are all effective clinical strategies.

Identification of patients, creation of registries, and effective recall and reminder systems have all proven efficient in improving immunization rates.

Benchmarking organizations and national policy should emphasize guideline implementation strategies for improving immunization rates as one of the initial efforts in chronic disease management. Lastly, organizational strategies for immunization of patients with diabetes could serve as a model for national efforts in chronic disease management.