The just-published third edition of the Guide for Adult Immunization [2] is a collaborative effort of the American College of Physicians and the Infectious Diseases Society of America. Written by the College's Task Force for Adult Immunization, it provides physicians and other health care providers with specific information on the use of immunogens in adults. In addition to updating earlier recommendations and providing information on new and future vaccines, it contains a new chapter on implementation strategies designed to "mainstream" immunization practices into adult care. Thanks to generous grants from a consortium of pharmaceutical companies, the Guide was distributed in September free of charge to College members in active patient care.

Applying recommendations for immunization will probably become part of the standard for quality assessment of adult care, as it is already in pediatric practice. This trend further heightens the need for recommendations that are well founded and periodically reexamined in light of current epidemiologic and immunologic evidence. After critical review, the Task Force has made several new recommendations that are not currently advised by other groups [3, 4]. Chief among these are the following recommendations:

1. Age 50 years should be a time for review of preventive health measures, with special emphasis on evaluating risk factors that would indicate a need for giving pneumococcal vaccine and initiating annual influenza immunization.

Almost one third of Americans aged 50 to 64 years have risk factors for invasive pneumococcal disease, yet fewer than 10% of those with risk factors have received the vaccine.

2. Persons who receive pneumococcal vaccine before age 65 years because of their risk factors should be reimmunized at age 65 years, provided at least 6 years have passed since they received the first dose of pneumococcal vaccine.

After primary immunization, antibody levels and protective efficacy gradually wane, and hypersensitivity reactions do not increase in persons reimmunized after 6 years. Although the boosting of immunity with repeated doses of polysaccharide vaccines is suboptimal, reimmunization is the most prudent policy pending the development of improved (conjugated) pneumococcal vaccines.

3. Special emphasis should be given to ensuring that all adults have completed a primary immunization series with tetanus and diphtheria (Td) toxoids, followed by a single midlife Td booster at age 50 years for persons who have completed the full pediatric series, including the teenage/young adult booster. The recommendation for Td boosters as part of wound management is unchanged.

This is an equivalent alternative strategy to the current recommendation for routine tetanus and diphtheria boosters every 10 years [3, 4]. Most patients with tetanus (40 to 60 cases per year) and diphtheria (0 to 5 cases per year) have not completed a primary series of immunization with the tetanus and diphtheria toxoids. Epidemiologic evidence indicates long-term protection after primary immunization and an excellent booster response to Td after intervals as long as 35 years. Once fully immunized, frequent routine boosters are not cost-effective [6].

4. The use of amantadine-rimantadine prophylaxis for influenza A should be more cautious.

Many physicians have expressed concern about adverse neurologic reactions to amantadine in their elderly patients. Rimantadine is expected to be better tolerated.

5. Serologic response to hepatitis B immunization should be assessed in all vaccine recipients older than 30 years.

Seroconversion rates diminish with age [7].

Publication of the Guide for Adult Immunization is the single most visible activity of the Task Force on Adult Immunization. The Task Force, through its ongoing representation on national advisory committees and communications in other College publications, will, however, periodically comment and advise on new vaccine products and advocate improving immunization practices focused on adults. Notable successes of preventive medicine in recent years have included marked reductions in deaths from cardiovascular disease, lung cancer, and automobile injuries. With heightened priorities from the medical community, the public, and the government, a similar opportunity exists for reducing morbidity and mortality from vaccine-preventable diseases in adults.