Pneumococcal conjugate vaccine in adults: Let's see what happens.

The recent recommendation for the use of the 13-valent pneumococcal conjugate vaccine (PCV13) in adults 65 y of age and older, provides a new tool for preventing disease in this at-risk population. The conjugate vaccine induces a T-cell dependent response, which distinguishes it from the polysaccharide vaccine and could provide the longer-term protection necessary to have a significant impact in this population.

Pneumococcal conjugate vaccine for adults: a new paradigm.

A 13-valent pneumococcal conjugate vaccine has been studied in adults aged ≥ 50 years to compare the immune response to that induced by the 23-valent pneumococcal polysaccharide vaccine, which has been the standard of care over the past 30 years. The results demonstrate that adults, regardless of whether they are naive or previously vaccinated with the polysaccharide vaccine, have an overall superior antibody response when vaccinated with the conjugate vaccine compared with the pneumococcal polysaccharide vaccine. More importantly, the nature of the response is indicative of a T-cell-dependent response that elicits immunological memory and, therefore, primes the immune system for either natural exposure or subsequent booster vaccination with either conjugate or polysaccharide vaccine. The conjugate vaccine, which has been successful in reducing pneumococcal disease in children, now provides a new approach to preventing pneumococcal disease, including community-acquired pneumonia, in adults.

Advances in pneumococcal disease prevention: 13-valent pneumococcal conjugate vaccine for infants and children.

A 13-valent pneumococcal conjugate vaccine (PCV13), developed with the same chemistry used for the 7-valent PCV vaccine (PCV7) and with the goal of expanding serotype coverage, was clinically evaluated in the United States and Europe and found to induce capsular-specific antibody responses comparable to those of PCV7 for the common serotypes, with robust responses to the 6 additional serotypes. In addition, PCV13 has a similar safety profile to PCV7 and can be given routinely to infants and children, ideally as a 3-dose primary series in the first year of life, with a booster dose in the second year. Children who have initiated their vaccination program with PCV7 can transition to PCV13 at any point in the schedule. Children aged ≥15 months who have been completely vaccinated with PCV7 can receive a single dose of PCV13 to induce immunity to the 6 additional serotypes.

Establishing government-operated vaccine programs: an industry perspective.

During 2000-2002, shortages of numerous routinely administered pediatric vaccines occurred. The reasons for these shortages were varied, but they included policy, manufacturing, and regulatory issues. The use of government manufacturing programs has been proposed as a way to stabilize the fragile vaccine supply and to prevent periodic shortages. Although such programs might be useful for defense needs, it is likely that such an approach would have limited value for routinely administered vaccines. Each of the vaccine components would require a dedicated manufacturing facility, and many components are administered in combination vaccines. Timing is also an important consideration. The restarting of an idled manufacturing facility would take many months; in addition, it often takes nearly 12 months to produce and release a single lot of vaccine. Finally, government-owned programs would face the same issues of regulatory changes, technological advancements, and facility updates as non-government-owned programs do--all of which would require sustained operation and investment. A secure and stable vaccine supply is best built by establishing the importance and value of our vaccine programs, which would, in turn, provide incentives to manufacturers to build capacity and inventories.

Strengthening the supply of routinely recommended vaccines in the United States: recommendations from the National Vaccine Advisory Committee.

Between late 2000 and the spring of 2003, the United States experienced shortages of vaccines against 8 of 11 preventable diseases in children. In response, the Department of Health and Human Services requested that the National Vaccine Advisory Committee (NVAC) make recommendations on strengthening the supply of routinely recommended vaccines. The NVAC appointed a Working Group to identify potential causes of vaccine supply shortages, develop strategies to alleviate or prevent shortages, and enlist stakeholders to consider the applicability and feasibility of these strategies. The NVAC concluded that supply disruptions are likely to continue to occur. Strategies to be implemented in the immediate future include expansion of vaccine stockpiles, increased support for regulatory agencies, maintenance and strengthening of liability protections, improved communication among stakeholders, increased availability of public information, and a campaign to emphasize the benefits of vaccination. Strategies requiring further study include evaluation of appropriate financial incentives to manufacturers and streamlining the regulatory process without compromising safety or efficacy.

Recent progress in the development of vaccines for infants and children.

Infectious agents do not respect national or international boundaries. Attempts to prevent their spread, and the diseases which they cause, involve implementing vaccination as widely and as appropriately as possible. The principles of vaccination against infectious agents are now being applied to cancer and other non-infectious conditions. In order to understand where modern vaccinology is heading, it is necessary to first examine individual components. This brief overview examines the following: Streptococcus pneumoniae, Neisseria meningitidis, varicella zoster, measles, rotavirus, HIV, influenza, "emerging" viral infections and cancer.