Volume 24, No. 2 - June 1999                     Published by the National Foundation for Infectious Diseases

Preventable diseases long-since forgotten may be making a comeback, health officials warned at a press conference sponsored by the National Foundation for Infectious Diseases (NFID). Controversies about vaccine use as well as drops in immunization levels for diseases considered "historical" are being associated with disease outbreaks and deaths worldwide. This, coupled with the widespread growth of multi-resistant strains of organisms, is posing a potential health risk, warned health officials.

"History will repeat itself," said Bruce G. Gellin, MD, MPH, staff director of the Vaccine Initiative, an independent resource providing clear, balanced, and scientific information about immunizations. Controversies about vaccine use launched on the Internet, raised in the media, and spoken about in state legislatures around the country, coupled with the public's now abstract concept of diseases that threatened children only a generation ago, have begun to erode the public's trust in immunizations, he said.

Dr. Gellin was one of several infectious disease experts speaking to journalists at the fourth Richard J. Duma/NFID Annual Press Conference and Symposium on Infectious Diseases held on April 22, 1999, in Washington, DC. NFID conducts the annual press conference, honoring former NFID President and Executive Director Richard J. Duma, MD, PhD, in support of its mission of educating the public about infectious diseases.

William J. Martone, MD, NFID's senior executive director, cited the importance of the annual press conference: "The press conference represents a crucial opportunity for NFID to assist the press in interpreting scientific information for the general public. This long-term approach, along with the active solicitation of feedback, ensures that the public receives the most accurate information available."

Speakers at the press conference focused on such issues as restoring the public's trust in vaccinations, the rise in drug-resistant tuberculosis, the expected increase in hepatitis C deaths, the genital herpes epidemic, and the role of chlamydia in atherosclerosis.

"Vaccines are the most powerful tools we have to prevent serious infectious diseases and their consequences," said Dr. Gellin. "In some ways, immunization has become a victim of its own success." Once immunization prevents a disease that was once common, many tend to forget about the seriousness of what the disease caused. As a result, "when immunization levels drop, disease returns," he said.

To help address these concerns, the Infectious Diseases Society of America and the Pediatric Infectious Diseases Society jointly developed the Vaccine Initiative a special education and communication project designed to provide parents, physicians, policy makers, and journalists with scientifically-based information about vaccines.

For the first time in several decades, the world may be facing the return of an incurable form of tuberculosis (TB) an airborne disease that destroys the lungs and other organs, said consumer advocate Ralph Nader, founder of the Princeton Project 55 TB Initiative. Multi-drug resistant (MDR) strains of the disease are cropping up all over the world. "The federal government and the American public have dismissed tuberculosis as a disease of the past," said Nader. "Nothing can be further from the truth about the world's biggest single infectious killer." Globally, every second someone new is infected with TB, and one person dies every 10 seconds from TB.

Nader's Princeton Project is a nonprofit, public interest organization dedicated to encouraging more effective involvement in combating social problems that face the nation. The mission of the TB Initiative is to increase public awareness of tuberculosis, to encourage US leadership of tuberculosis prevention and control programs, and to facilitate tuberculosis vaccine development through government and industry support.

"During 1993 and 1997, 43 states and the District of Columbia reported cases of TB that were resistant to the two most important front-line drugs used to treat TB," said Kenneth Castro, MD, director, Division of Tuberculosis Elimination at the Centers for Disease Control and Prevention (CDC).

Approximately 50 million people are believed to be infected by MDR-TB, with treatment being significantly more difficult and costing up to 100 times as much as a regular TB patient. These figures are alarming considering that much can be done to prevent this "Ebola with wings" as it is called by officials at the World Health Organization. Directly observed treatment shortcourse (DOTS) is an effective treatment for TB that involves at least a six-month antibiotic regimen and can prevent the development of further drug resistance if used properly.

"Health departments must expand programs to ensure that persons with TB disease and latent infection complete prescribed regimens," said Dr. Castro. It is also important to make the public aware of the continued health risks that the disease poses.

Even though the number of TB cases has declined in the United States over the past six years, TB is still the number one single infectious disease killer worldwide, taking nearly 3 million lives each year. Declared a "global emergency" by the World Health Organization in 1993, TB is responsible for more than one-quarter of all preventable adult deaths in the developing world. "TB does not stop at US borders, nor can prevention efforts," claimed Dr. Castro. "TB has to be fought globally to protect locally," he added. Advocacy organizations including Nader's Princeton Project 55 TB Initiative are encouraging Congress to appropriate $60 million in foreign assistance specifically for TB.

Genital herpes affects 1.3 million people every year in the United States, yet little attention is given to this common sexually transmitted disease. "There were 1.1 million new cases of herpes simplex virus type 2 (HSV-2) infections every year in the 1980s," said Gray Davis, PhD, president of Sexual Health Communications based in Durham, NC. Recent surveys show that almost 22 percent of Americans are now infected with HSV-2. "How can an epidemic of this size be forgotten?" she asked.

Dr. Davis said one answer was the public's focus on the AIDS epidemic in the early 1980s. "So much necessary focus was placed on the HIV crisis that non-life threatening infections were de-emphasized," she said. "However, given the link between HIV and HSV and the sharp rise in HSV seroprevalence in our teenage population, herpes can not be forgotten any longer."

Dr. Davis added that the 30 percent increase in herpes rates during the 1980s indicates that most people do not consider themselves at risk for herpes. In order to decrease transmission, she recommended better disease diagnosis, better screening and education, and a strategy to prevent transmission.

Anyone who is sexually active is at risk for infection. Herpes, while usually not life-threatening, is contagious and causes small red, painful bumps that become blister-like in the genital area. As with other sexually transmitted diseases, women are at the highest risk of infection.

The United States is not unique in its high rates of herpes cases. Most countries around the world are presenting similar figures, according to Dr. Davis. "Since recurrences are often very mild and few patients are aware that they are infected, the infection is likely to continue to rise at double-digit rates without an intervention," Dr. Davis said.

Dr. Davis recommends developing a national policy regarding whom to screen for HSV infection and how to counsel them as well as developing a disease management strategy once a person or their partner is diagnosed.

"Hepatitis C virus (HCV) infection and disease is an increasing public health concern," said Leslye D. Johnson, PhD, chief of the Enteric and Hepatic Diseases Branch at the National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH). "Without more effective therapies that produce recovery, the CDC predicts that deaths due to HCV will double or triple in the next 15 to 20 years due simply to the length of time most people in the United States have been infected."

Currently, about 4 million people in the United States are persistently infected with the virus. HCV, a blood borne infectious agent which infects and damages the liver, causes between 8,000 and 10,000 deaths each year and accounts for almost half of the approximately 4,000 liver transplantations done each year. People who currently or ever had multiple sex partners or used injection drugs are most at risk for this disease, but for 10 percent of cases, no risk factor is identified.

Because most people's infection and disease is relatively symptom-free, approximately 50 percent of chronic carriers do not know they have HCV. Since the disease is progressive, it is important that infected individuals determine if they have the disease. Both alcohol and infection with other hepatitis viruses can hasten the progression. "Thus, if they know that they are infected, individuals can help themselves by not using alcohol and by getting vaccinated to prevent hepatitis A and B," Dr. Johnson added.

Currently, there are four approved therapies that for a small percentage of people eliminate the virus; however, all have significant side effects, and there is a poorer than average response in most American patients with who are infected with genotype 1.

To help counteract the alarming disease trend and sub-optimal treatment, Johnson put forth the following research priorities: develop more effective and safer treatment options, better understand the mechanisms of recovery and persistence, and define the viral replication and pathogenic processes.

Does Chlamydia pneumoniae, a microorganism that causes pneumonia and other respiratory infections, cause heart disease? "That C. pneumoniae and atherosclerosis are associated has been clearly demonstrated, but whether the association is causal is not yet known," said J. Thomas Grayston, MD, professor of epidemiology at the University of Washington.

The association was first demonstrated by finding that persons with atherosclerosis, commonly referred to as hardening of the arteries, have specific antibodies showing previous C. pneumoniae infection more frequently than persons without disease. Atherosclerosis in arteries supplying blood to the heart (coronary arteries) is the most common cause of heart attacks.

In a series of studies carried out by researchers at the University of Washington, C. pneumoniae was found in at least half of the atherosclerotic lesions studied from coronary, carotid, popliteal/femoral arteries, and the aorta. In addition, several investigators have grown C. pneumoniae in cells found in artery walls. Although these studies do not prove that C. pneumoniae causes atherosclerosis, "evidence from animal model studies and human treatment trials will allow more direct inference of causality," Dr. Grayston explained.

Preliminary studies in rabbits and mice have suggested that C. pneumoniae infection can both initiate and accelerate the atherosclerotic process. Dr. Grayston is hopeful that these studies, if repeated on a larger scale and observed over longer periods of time, will provide more definitive evidence about the organism's causal relationship to atherosclerosis.

Three recently reported retrospective studies examined the effect of antibiotic usage on subsequent coronary artery disease events. Two of the studies found that patients who took antibiotics effective against C. pneumoniae had a lower incidence of coronary events than controls.

There also have been three pilot prospective antibiotic treatment trials, with two positive and one negative. These studies, although interesting, were too small for reliable results, Dr. Grayston said. However, two trials of adequate size and duration are underway to determine if antibiotic treatment of coronary artery disease can reduce the frequency of coronary events compared with placebo controls.

"If successful, such trials would add a new treatment method for coronary artery disease and would suggest that C. pneumoniae plays a role in the process that leads to coronary heart disease events," said Dr. Grayston.

Dr. Grayston believes that it will take an accumulation of many animal and human studies to determine if C. pneumoniae plays a causal role in atherosclerosis. "If it does, the long term hope for primary prevention will be a vaccine effective against C. pneumoniae infection," he said.

The 4th Richard J. Duma/NFID Annual Press Conference and Symposium on Infectious Diseases was supported, in part, through unrestricted educational grants from Aviron, Glaxo Wellcome Inc., Kimberly-Clark Corporation, Merck & Co., Inc., Pfizer Inc., Pharmacia & Upjohn, Inc., Roche Laboratories, and Zeneca Pharmaceuticals.

• Photos taken at the Duma Press Conference