Division of Disease Control and Health Protection

May 20, 1999

The Epidemiology Grand Rounds, a monthly, one-hour audioconference conducted by the Bureau of Epidemiology, focuses on issues of epidemiologic interest to Florida public health providers, including; county health department directors and administrators, nursing directors and nurse epidemiologists, laboratorians, and other interested parties. Each session features a formal PowerPoint presentation followed by an opportunity for audience interaction. Presenters include representatives of the State Department of Health, county health departments, schools of public health and other experts in epidemiology and associated specialties. Richard S. Hopkins, M.D., MSPH, Florida’s State Epidemiologist, will coordinate the presentations. Assistance with PowerPoint can be provided.

Grand Rounds Session 3 will be held May 25th, 1999, from 11:00 a.m. - 12:00 p.m. EST. This Audioconference will spotlight Dr. Mary Jo Trepka, M.D., MSPH, Director of Epidemiology and Disease Control, Miami-Dade County Health Department, Florida Department of Health. Dr. Trepka will present "An Outbreak of Typhoid Fever in South Florida Associated with an Imported Commercial Food." This presentation will describe the 1999 South Florida typhoid fever outbreak investigation methods and results. Upcoming topics and presenters will also be posted in future Epi Updates.

1999 Audioconference Dates:

May 25, June 29, July 27, August 31, September 28, October 26, November 30, and December 28.

Please consider the following tips for making the Grand Rounds more useful and enjoyable:

Never call in using a cellular telephone or cordless headset.

• Leave your telephone "mute button" on during the call (except when asking questions).
• Do not put your phone on "hold" and leave the call.
• Dial-in on time.

Travel to countries with high rates of infection with the hepatitis A virus (HAV) accounts for six percent of HAV infections in the United States [1]. The risk of hepatitis A for U.S. citizens traveling abroad varies with living conditions, length of stay, and the incidence of hepatitis A infection in areas visited [2]. In general, travelers to northern and western Europe, Japan, Australia, New Zealand and North America (except Mexico) are at no greater risk of infection than they would be in the U.S. Areas of the world with intermediate or high rates of hepatitis A do pose an increased risk for travelers (see Figure below).

For travelers to developing countries, risk of infection increases with duration of travel and is highest for those who live in or visit rural areas, trek in back country, or frequently eat or drink in settings of poor sanitation. Recent studies have shown that many cases of travel-related hepatitis A occur in travelers with "standard" tourist itineraries, accommodations, and food and beverage consumption behaviors.

We report on the demographics, destinations, and travel durations of 55 hepatitis A cases who had a history of international travel and were reported to the Florida Department of Health in 1998.

In 1998, 592 cases of hepatitis A were reported to the Surveillance of the Florida Department of Health’s Bureau of Epidemiology. Approximately nine percent of these cases (N=55) reported a history of international travel during their incubation period (the period two to six weeks prior to illness). These data were obtained from the CDC Viral Hepatitis Case Record (form 53.1).

The gender, racial, and age distributions of these cases were examined. Frequency distributions of travel destinations and travel duration were generated. The SAS statistical package (Release 6.12 for Windows) was used for several calculations.

Of the 55 cases, 20 were females (36.4%). The mean age of the travelers was 23.3 years and the median age was 23 years (range: 3 years to 51 years).

Table 1 shows the distribution of race-ethnic groups (frequency and relative frequency). The majority of the cases (56.4%) were Whites of Hispanic ethnicity.

Table 2 displays the frequency distribution of the travel destination. South America/Central America was the most common destination (74.5% of cases).

Table 3 displays the distribution of the duration of the trip. The majority of travelers stayed abroad for more than seven days (69.1%).

In conclusion, the majority of Florida hepatitis A cases (reported in 1998) with an international travel history were White Hispanics. The most popular destination was South and/or Central America, and overall, the majority of travelers spent more than seven days abroad.

Given the high percentage of Hispanics and the fact that Central/South America was the most common destination, it is possible that many of these individuals were traveling back to a family home. This is similar to what is seen with malaria cases and makes prevention difficult because many of these individuals think that the "home country" is a safe place. However, information on the purpose or the nature of the trip was not available for this analysis.

Before visiting countries where hepatitis A is endemic, travelers should be immunized against hepatitis A. The Advisory Committee on Immunization Practices (ACIP) has issued recommendations on the prevention of hepatitis A through active and passive immunization [3]. In developing countries, travelers should minimize their exposure to hepatitis A and other enteric diseases by avoiding potentially contaminated water or food [2]. Travelers should avoid drinking water (or beverages with ice) of unknown purity and eating uncooked shellfish or uncooked fruits or vegetables that are not peeled or prepared by the traveler.

The 5th edition of CDC's "Epidemiology and Prevention of Vaccine-Preventable Diseases" (also known as the "Pink Book") has just been released.

The "Pink Book" is CDC's definitive resource book on vaccines. It condenses a large amount of disease and vaccine information into an easily readable form so that it can be used as a quick

reference in busy clinics and offices. It is also used as the textbook to support the National Immunization Program's (NIP) training courses on epidemiology and prevention of vaccine-preventable diseases via satellite.

CAN'T DOWNLOAD THE SLIDES? Downloading the slides can be a difficult or impossible project for many computers. But don't be dismayed! These slides are part of a FREE resource packet available from CDC. The resource is entitled "Immunization of Adolescents with Hepatitis B Vaccine: An Educational Resource."

Public and private sector health professionals who are interested in developing their own educational programs to promote adolescent hepatitis B vaccination can get this free educational resource, which includes the slides that are on the Website plus an accompanying resource guide, by requesting it from the National Immunization Program of CDC.

The best way to order "Immunization of Adolescents with Hepatitis B Vaccine: An Educational Resource" is to use the CDC/NIP Resource Request List located at the NIP Website. Download the CDC/NIP Resource Request List. Information on how to order is at the beginning of the list. You can also obtain the Resource Request List by fax. Call the CDC fax back system, 888-CDC-FAXX (888-232-3299), and request document #130011, enter your fax number and the Resource Request List will be faxed to you.

The Advisory Committee on Immunization Practices (ACIP) consists of public health experts, scientists and physicians in clinical practice who make annual recommendations on the use of influenza vaccine and antiviral drugs. Their latest influenza report was published as a supplement to MMWR on April 30, 1999.

Based on virus strain surveillance the ACIP has determined the components of the 1999-2000 influenza vaccine. The trivalent vaccine will include the hemagglutinin antigens from: A/Beijing/262/95-like (H1N1), A/Sydney/5/97-like (H3N2) and B/Beijing/184/93.The same strains were included in the 1998-1999 vaccine. However, the protective antibody titers from vaccination can decline quickly so annual boosters are recommended regardless of the components of the vaccine. The inactivated vaccine currently in use in the United States is 70-90% effective in healthy persons younger than age 65.

Intranasally administered, cold-adapted, live attenuated, influenza virus vaccines (LAIVs) have been under development in the United States since the 1960s. The belief is that by allowing the virus in the vaccine to replicate in the respiratory tract both a local (mucosal) and systemic immune response would be induced. The intranasal vaccine would also be easier to administer. So far, LAIV vaccines appear to prevent disease as effectively as the injected form. Final FDA approval is expected within the next 2 years.

The vaccination target groups remain the same as in previous years:

Several studies indicate that small children (< 5 years) and adults between 50 and 64 years may be at increased risk for complications of influenza. If these preliminary findings can be verified in further studies, routine vaccination will most likely be recommended for healthy individuals in these age groups as well.

Persons in high-risk groups should consider getting vaccinated before travelling to other continents during their local influenza season. Vaccination is recommended for travel to the tropics, to temperate regions of the Southern Hemisphere during April to September and when travelling as part of a large organized tourist group with people from areas of the world where influenza viruses are circulating.

In the March issue of the 1936 State Board of Health "Florida Health Notes", Dr. W. A. McPhaul, State Health Officer, took the opportunity to speak out on the many "disasters that overtake young people." Some interesting excerpts from that article follow and a cartoon that stimulated his interest in the subject is available as a separate file.