Friday, October 22, 2021

Immunizations for pneumonia and influenza

By Nelson Marcopolous, Senior Surveillance Analyst, US Public Health Service, Centers for Disease Control and Prevention (CDC)

The Advisory Committee on Immunization Practices held a teleconference on July 18, 2017 to discuss new strains of tuberculosis and influenza. Of special interest to vaccine makers was finding ways to help improve the efficacy of pneumonia booster vaccines. While these older vaccines have declined in their effectiveness due to immunization by other means, it has become clear that we still need a vaccine that can protect infants from pneumococcal pneumonia (PB) disease.

PB is the predominant cause of pediatric death from pneumococcal disease and the second leading cause of adult-onset pneumonia and meningitis. In the United States, almost every year there are 7,000 cases of PB, which account for 10,000 hospitalizations and 2,000 deaths. The major pathogen causing PB is pneumococcus, or P. pneumoniae. P. pneumoniae is a bacterium that causes several pneumonia and meningitis infections.

A review of the evidence suggests that four distinct types of pneumonia/tuberculosis vaccines work best against a specific type of bacterium and type of person: pneumococcus isolate (PSA), PSA plus a pneumococcal polysaccharide vaccine (PPSV) or PPSV plus an inactivated pneumococcal vaccine (Inocardiql-SPV). As new strains of PSA become available and underclinical vaccines against these strains become available, it should become clear whether the new vaccines do better than the most commonly used vaccines at protecting against these strains.

Until recently, no effective vaccine to protect against the newest strains of PSA and E in the United States was available. The last effective vaccine against PSA was in 1992. Currently there are over 70 strains of PSA in clinical use in the United States.

New strains of PSA tend to develop each year, bringing with them new bacteria strains that can be the targets of new vaccines. The new HACR19 and HACR19+ strains become available each year, and PSA becomes readily identifiable for vaccine development. The PB vaccine makers have looked toward this new opportunity in the past and have found promising results in this first generation of PSA vaccines. More recently, two novel vaccines are now in development. One (NGE-H5/BUGRVSJ01) is a chimpanzee antigen vaccine designed to prevent neonatal Acinetobacter baumannii pneumonia. The other (NGE-H5/BUGRVSJ01) is a mammalian antigen vaccine designed to prevent Pneumococcus colitis (PBS). More recently, two new strains of PSA have been identified, respectively A, S, and W18, which also indicate an opportunity for new vaccine development. To date, all of these new strains of PSA have not become vaccine-relevant. New TB vaccines were first developed and made available to people in the mid-1900s. By 1999, 26 countries were screening for tuberculosis. As new drugs, vaccines, and diagnostics became available, there was a plateau of TB-related deaths. Over the past 20 years, the incidence of TB has continued to decrease in industrialized countries.

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