a SLACK Incorporated newspaper
September 1998
ATLANTA - The 1998 Jeryl Lynn Hilleman Merck Company Foundation Endowed Lectureship was recently awarded to Samuel L. Katz, MD, Wilbert Cornell Davison Professor and chairman emeritus of pediatrics at Duke University School of Medicine, Durham, N.C. The award was given here during the recent 32nd National Immunization Conference.
Katz began his acceptance by stating that few physicians have seen a child with smallpox, measles, polio and many other vaccine-preventable diseases with now record-low incidence rates. And, despite the past challenges in vaccine development and acceptance by providers and the public, the number of vaccine-preventable diseases is increasing.
However, the current number of possible injections recommended by the childhood immunization schedule can total 16 before the age of 2; a schedule which is now dubbed the "pin cushion problem," Katz said.
"Our very success relies on an increasingly complex immunization schedule," he said.
Katz also mentioned anti-vaccine groups which attribute false adverse events to vaccines. "It's a paradox. Our success is our worst enemy because young parents today have seen few of the diseases against which we immunize their children."
While the Internet can be an excellent tool for researching vaccine information, it also provides a wealth of false information. Therefore, the newly established Vaccine Initiative, sponsored by the Infectious Diseases Society of America and the Pediatric Infectious Diseases Society of America, is an attempt to provide vaccine information from a neutral source to parents, health care workers, media and legislative groups, Katz said.
"We need to assess the magnitude of how much parental concern and anxiety exists regarding these vaccines and then come up with solutions of how to mitigate these concerns," he added.
Combination vaccines are one way to prevent additional injections as new vaccines are developed.
"Instead of single injections of different antigens, we can look forward to having combination antigens," he said. "We know they are greatly advantageous, they reduce the number of injections, they increase compliance, decrease the office inventory and hopefully will facilitate the introduction of new vaccines."
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The development of combination vaccines is very complex. Development challenges include physical and chemical incompatibilities, immunologic interference, size of combined product and shelf-life of the product.
Katz anticipates that combination products in the near future will include diphtheria-tetanus-acellular pertussis vaccine (DTaP) combined with inactivated poliovirus (IPV) and DTaP with Haemophilus influenzae type b (Hib), IPV, and HepB, among others. Several combinations are already licensed in Europe and Canada.
The World Health Organization (WHO) is also working to decrease the number of injections. Katz said they have worked primarily with tetanus toxoid and have shown biodegradable microspheres can be injected as a single injection and these antigens would be released in a pulsed fashion; rather than three injections of DTaP, there could be one injection with the antigens released every few months like the normal schedule.
Alternatives to injections include needle-free devices, dermal patches and mucosal routes for administration are additional ways to solve the pin cushion problem. There are several advantages to mucosal vaccines: no need for needles/syringes which reduces the risk of contamination, easier to administer and are cheaper to manufacture.
Currently licensed mucosal vaccines include oral poliovirus vaccine (OPV), typhoid vaccine; others being consider for licensure include oral cholera and rotavirus vaccines and an intranasal influenza vaccine for pediatric use.
Incidence rates of otitis following the influenza vaccine's administration dropped compared with placebo.
A vaccine is in development for respiratory syncytial virus (RSV), the most common cause of lower respiratory infections in infants. In the United States, RSV causes more than 100,000 infant hospitalizations and 4,500 deaths a year.
Pneumococcus is also a major concern. Antibiotic resistance of this organism adds additional pressure for vaccine development, Katz said. Conjugated pneumococcal vaccines have shown the greatest success; all the vaccines under clinical trials include the four serotypes: 14, 19, 6 and 23, which have been most involved with antibiotic resistance.
The incidence of meningococcal disease in the United States is not significant, but routine meningococcal immunization could be considered if conjugate vaccines were developed, he said. An outbreak earlier this year in Rhode Island resulted in a proclamation that everyone between 2 and 22 years of age receive the meningococcal vaccine. Within four weeks, 186,000 people were immunized.
The future is expected to focus on adolescent immunization. Vaccination against hepatitis B and varicella are already required for entry into more middle schools, and DTaP and influenza may be added to that list, Katz said.
Vaccines for sexually transmitted diseases will eventually be available, and adolescents are an ideal population for their use, he added. Vaccines are being developed for chlamydia, human papillomaviruse and herpes simplex type 2.
To protect newborns against disease common early in life, immunization of pregnant women in their third trimester may become more accepted. WHO has been successful in eliminating neonatal tetanus by giving the mother two injections of tetanus toxoid during her third trimester. These immunization methods have not been attractive to manufacturers in the United States for fear of adverse pregnancy outcomes being falsely attributed to the vaccination.
Much of Katz's career has been dedicated to infectious diseases, principally on vaccine research and development. He is an honors graduate of Dartmouth College and Harvard Medical School and completed a medical internship at Beth Israel Hospital.
While working with John Enders, MD, at Boston Children's Hospital, Katz helped develop the first attenuated measles virus vaccine which is the projenitor of nearly all measles vaccines currently in use.
Aside from measles, Katz has conducted research on smallpox, polio, rubella, pertussis and others. His current research is focused on pediatric AIDS. He was also a member of the Advisory Committee on Immunization Practices for 11 years and served as its chairman for eight. Walter A. Orenstein, MD, director of the National Immunization Program, described Katz as "a man who has served as doctor, teacher, mentor and researcher."
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