Many successes, many challenges with today’s immunization program

CHICAGO – The lessons learned in vaccinating the nation’s children were applied to preparing the country for a bioterrorism attack, according to Walter Orenstein, MD, the director of the National Immunization Program.

“The foundation built to educate and encourage childhood immunization was used to guide CDC, state and community preparedness efforts, especially with respect to the president’s recommendations for the use of smallpox vaccine,” Orenstein said here at the National Immunization Conference.

The smallpox vaccination program was the “first intensive, national, occupational adult immunization program,” he explained. Recommendations to produce a smallpox vaccine were developed and refined, training and education was undertaken, and vaccine safety systems were implemented. Smallpox vaccination programs are here to stay, Orenstein warned the public health officials who attended the conference.

He called the process disruptive to the normal public health routine, but added that the public health system cannot “lose sight of what we have accomplished against natural threats, the diseases that we have made so much progress in reducing, and in many cases eliminating in the United States.”

And there are many successes.

“With the exception of pertussis, we have reduced all of them [childhood vaccine preventable diseases] by 98% or more and the vast majority by 99%,” Orenstein said, adding, “This is a remarkable accomplishment.”

In 1990, there were 28,000 cases of measles in the United States; last year, there were 37. Mumps went down from 4,866 cases in 1988 to 238 in 2002, and rubella went from 225 cases to 14 in the same interval. “When I first saw this, I thought my staff had made a mistake, I said, ‘please give me the right number’ – it is the right number,” he joked.

Although varicella vaccine coverage is only 76%, the vaccine has still produced remarkable results. “I think one of the most rewarding achievements is the decrease in varicella deaths, particularly in individuals younger than 20 years of age, where the major focus of immunization is; to a lesser extent in 20- to 49-year-olds, probably as a result of herd immunity being induced by vaccination, and to the least extent, persons 50 and above; but nevertheless an apparent reduction. Our 2010 goal is 90% reduction in cases,” he said.

“We’ve made major progress in improving coverage for a number of immunizations. Hepatitis B vaccine [HepB] coverage for 2-year-old children in 1993 was 16%; in 2001 we were approaching 90%. For most vaccines we are either at or approaching 90% immunization coverage for 19- to 35-month-old children (median age 27 months).”

“The only disease going in the wrong direction is pertussis and that in large part is because we have a reservoir of pertussis transmission in adolescents and young adults. And we need a technological fix, a way of immunizing those populations, which we cannot do at this point,” he explained. Pertussis cases have actually increased from 3,450 in 1988 to 8,296 cases in 2002.

While most disease numbers are down, the number of diseases that children are protected against has increased. In 1988, children were vaccinated against measles, mumps, rubella, diphtheria, tetanus, pertussis and polio, and toddlers were vaccinated against Haemophilus influenzae type b (Hib). Today, children are vaccinated against those diseases, but also hepatitis B, varicella and Streptococcus pneumoniae. Infants are now vaccinated against Hib. Some areas also vaccinate children against hepatitis A.

“We now vaccinate children routinely against 11 vaccine preventable diseases, many more than when we were children and when today’s parents were children,” Orenstein explained.

While this is a remarkable achievement, it is also a challenge to every physician because of the number of injections children must receive by 18 months of age to be fully vaccinated.

The recent licensure of Pediarix should help, Orenstein said. “Prior to the licensure of Pediarix, it took 16 to 20 injections by 18 months of age to fully immunize a child, and an additional four injections by 18 years of age to complete the immunization series for the 11 diseases. Let’s look at a few office visits, now that we have Pediarix, which is a combined DTaP-HepB-IPV. At the two-month visit to vaccinate against seven diseases, including pneumococcal disease, Hib, diphtheria, tetanus, pertussis, polio and hepatitis B, it took four to five injections depending on which combinations you used. With Pediarix you can do it in three. By 18 months, excluding the birth dose of HepB, it took 16 to 20 before. It now can be done in 13 to 14. And by 18 years of age, you can get by with as few as 17 injections, whereas before, it took as many as 24. This is a significant breakthrough,” Orenstein said. “But it still is not a panacea. We need more. We still have, even with Pediarix, 17 to 21 injections by 18 years of age. It’s too many, and we need more combinations, but this is a step in the right direction.”

Vaccine progress

Although HepA is not universally required, the vaccine has still led to a decrease in cases. Prior to vaccine licensure in 1995, on average there were about 12 per 100,000 cases per year with some cycles in the United States. There has been a two-thirds reduction in hepatitis A (HAV) cases since the vaccine was licensed, he explained.

Internationally, there has also been progress on the vaccine front, especially against measles and polio. “Measles is the greatest vaccine-preventable killer of children even today. In 1990, the World Health Organization (WHO) estimated that over 1.6 million children had died. We are now down to under 800,000 deaths, but we still have a long way to go.”

Polio elimination is also on target. In 1988 when the World Health Assembly endorsed global eradication, polio existed on every continent except Australia and Antarctica. About 125 countries were endemic, and there were about 350,000 cases a year. Today, seven countries report about 1,900 cases.

But there are challenges ahead for anyone who vaccinates people, Orenstein said. “Securing stable and efficient vaccine financing; avoiding delays and shortages; assuring and maintaining vaccine safety; and fostering and achieving adult immunization. Adult immunization is important not just because it is a good thing to do, but because pandemic influenza is the ultimate bio-terrifying virus, it is a virus which bioengineers itself, creating large populations of susceptible people. We will see pandemic flu at some point, and we need to have an adult influenza infrastructure that can handle it. Finally, we have to manage smallpox-related demands. They are not going away, and we need to build our preparedness,” he said.

Vaccine development and vaccine production costs have increased dramatically, and physicians should expect higher costs as new vaccines are brought to market. “The days of the very cheap vaccines are over,” Orenstein said.

“We have asked the IOM to look at what the vaccine financing system should be in the U.S., and we anticipate their report sometime this summer. In the meantime, the administration has proposed some improvements for the Vaccines for Children (VFC) program, which, while not solving everything, will help in trying to establish a firm financial base.”

The administration has proposed three initiatives to Congress: improving vaccine access to underinsured children; removing vaccine price caps from public-sector vaccine purchases; and building a six month national stockpile of childhood vaccines by 2006 using VFC funds.

“A major guiding principle of these proposals is not to change the public-private market share. Manufacturers have expressed extreme concern that they do not want a bigger public market; it decreases their ability to control their destinies.”

Above all, Orenstein said, vaccine safety is a special obligation. “We need an infrastructure to maintain parent and public confidence. It starts with our Vaccine Adverse Event Reporting System, where we hear about reports and it triggers investigations.” It is important for physicians who suspect an adverse event to report it to VAERS.

Another challenge in the coming years will be fostering adult immunization. “We now realize with diseases like influenza we had been underestimating its health impact. Thirty-six thousand or more people die in an average influenza epidemic, and about 6,000 to 7,000 die annually from pneumococcal disease, about half of them in the elderly. We need to improve our efforts. And we are far short of our 90% goal,” Orenstein said.

The Centers for Medicaid and Medicare Services will now reimburse standing orders programs, which may help improve rates in hospitals, long-term care facilities, home-health care settings and other “places where there have been substantial missed opportunities for vaccination.”

In addition, the 2003 Medicare fee schedule almost doubles the vaccine administration fee for Medicare patients. The national average goes from $3.98 to $7.72, depending on the area.

For more information:

• Orenstein W. 2003 NIP Program Review. Presented at the 2003 National Immunization Conference: Building a Strong Foundation for Today’s Challenges. March 17-20, 2003. Chicago.