Galveston— Doctors and health officials have long worried that the low childhood immunization rates on the island were a quietly ticking time bomb.

Less than half of the children up to age 2 on Galveston Island were fully immunized, according to county health district estimates from 2002, the most recent data available.

“The only reason I can see why people would permit this is people don’t understand their children are at risk,” said Dr. Martin Myers, an associate director of the Sealy Center for Vaccine Development at the University of Texas Medical Branch and a professor of pediatrics and preventive medicine.

Myers is coordinating the university’s collaboration with the health district, state Department of Health and volunteers to raise the island’s immunization rate.

Galveston Island Infant Immunization Week begins April 24 and is marked by educational and publicity outreach and free vaccines provided by the state.

The effort is focused on the very young, who have a lower immunization rate than school-age children who must be current on their shots to attend classes.The vaccine-preventable diseases also tend to be more dangerous, and more contagious among the younger children up to 35 months of age.

The goal is to bring the numbers of those fully immunized up to 90 percent in three years.

Helped by a $60,000 grant from the Ronald McDonald House of Charities of Greater Houston-Galveston, the university already has begun to prepare.

The neighborhood-by-neighborhood strategy is inspired by the approach that helped propel Mexico’s immunization rates past those in the United States. Well known community members will be enlisted to help UTMB staff go door-to-door to identify eligible children.

The university also plans to conduct phone surveys both before and after immunization week to evaluate its effect on the immunization rate.

The hope is that the effort will become a blueprint for other communities to raise their immunization rates.

University students, employees and other volunteers are now going through stacks of immunization records, inputting them in ImmTrac, the state’s immunization registry.

The problem of low rates has befuddled UTMB doctors who say research has not been able to find socioeconomic or racial links.

“It doesn’t have a color,” said Dr. Christine Turley, an assistant professor in the department of pediatrics. “It doesn’t have a dollar sign tied to it.”

The vaccines in question cover a slate of diseases, including polio and whooping cough, that once ravaged the country and still wreak havoc during outbreaks and in developing countries.

Health officials say the perception that the diseases have been conquered here was partially to blame for the low rates.

An outbreak of measles in the Marshall Islands in recent months infected hundreds and killed three people. Outbreaks of measles also have been reported in Alabama and along the Texas-Mexico border, where investigators traced the root to travel to areas where the disease was more common.

Whooping cough has been making a comeback. In 2002, there were 8,296 cases reported, the most since the mid-1960s. Nine of those cases were in Galveston County.

Health district officials said most of the cases were children too young to have completed the series of immunizations against whooping cough. They caught the disease from older children or adults who would not feel the symptoms of the whooping cough as acutely.

It illustrates the “herd immunity” gained by having a high immunization rate: Without a sizable population of nonimmunized people, some diseases are left without a foothold to become an outbreak that potentially can infect the immunized.

The opposite can also be true. Vaccines are not 100 percent effective. Myers makes the point in presentations by talking about his fully-immunized grandson visiting for the day of fun at the beach while the adults worry he could be playing around people who carry the diseases because they are not immunized.

“If everybody got lazy and didn’t get immunized against the vaccine-preventable diseases, the diseases would come back,” said Chuck Chambers, an epidemiologist with the health district.

Health officials point to several reasons that Galveston’s immunization rate is lower than the state and national average. Poverty may play a role, as may suspicion of the vaccines.

Dr. Mark Guidry, executive director of the health district, said that without outbreaks of disease, people become complacent. Absent a visible and looming threat, immunizations became contingent on convenience for some people.

Some parents may neglect immunizations because they don’t like to see their children cry when they get the shots.

“In a sense, we are victims of our own success,” he said.

Health officials around the world also have had to contend with safety concerns about the vaccines that they say are unfounded.

England has seen a rise in the number of vaccine-preventable diseases as some groups have raised concerns that children receiving the measles-mumps-rubella vaccine could cause autism, a theory that health officials said was unsupported by research.

To illustrate the difference between causality and coincidence, Turley recalled a case she saw while practicing in Nevada.

One of her patients, a 4-month-old infant, missed an appointment to get vaccination shots. The child died the next day of a cause that was never determined. Turley said had the child made the appointment, the family’s search for a cause would have inevitably turned to the vaccines, even though they were not the cause.

It’s also possible that the city and county rates are not as far from the national and state rates as it appears, Chambers said.

The health district bases its numbers on random samplings of incoming kindergartners who must be brought current on their immunizations before starting school.

The state and national rates are based on telephone surveys.

Chambers said the differences in the methods meant the pre- and post-surveys would have to involve more than telephone interviews if the results were to be compared to the health district’s assessments.

“Whatever results they get will have to be interpreted carefully because of differences in methods,” he said. “There are problems with telephone surveys because not everybody has phones and not everybody is listed. But it’s a data collection method. The results just have to be interpreted carefully.”

Information

• For information about Galveston Island Infant Immunization Week, to volunteer or general questions about vaccinations, call (409) 747-1247.
• More information can also be seen on the Internet at www.utmb.edu/scvd/giii.htm

List of diseases vaccines prevent

• Diphtheria — A bacterial infection of the throat or skin. Throat infection is the more serious type, causing the formation of a tough membrane on the tonsils, soft palate, larynx and other parts of the respiratory tract that can block breathing.
• Tetanus — Also known as lockjaw. It’s most often caused by contaminated puncture wounds and often fatal. Symptoms include muscle spasms that can be so violent they fracture the spine.
• Pertussis (whooping cough) — Infection that causes severe coughing that can interfere with breathing. Its name comes from the distinctive “whoop” sound the infected make when gasping for air.
• Poliovirus — Attacks the nervous system and in severe cases can cause paralysis, atrophy of muscles and permanent deformity.
• Measles — Extremely contagious disease caused by a virus. Early symptoms resemble a cold. Those infected eventually develop white spots on the insides of their cheeks and a red rash spreading from the face.
• Haemophilus influenzae — Bacteria that can cause meningitis, an infection of the lining of the brain and spinal cord.
• Hepatitis B — Virus often spread sexually and through blood transfusions. Infections can become chronic and cause cirrhosis of the liver.
• Varicella zoster — Virus that causes chickenpox, marked by a blistery red rash.

— University of Newcastle upon Tyne

Vaccine facts

A schedule of when children should receive the slate of vaccines recommended by the Centers for Disease Control and Prevention.

• Diptheria, tetanus toxoids and pertussis vaccine; 4 doses; 2, 4, 6 and 15 months.
• Measles, mumps and rubella; 1 dose; 15 months
• Inactivated polio vaccine; 3 doses; 2,4,6, and 15 months.
• Pneumococcal conjugate; 4 doses; 2,4,6, and 15 months
• Haemophilus influenza type B vaccine; 4 doses; 2, 4, 6 and 15 months.
• Hepatitis B vaccine 3 doses at birth and age 2 and 12 months.
• Varicella zoster vaccine 1 dose at 15 months.

— Source: Centers for Disease Control and Prevention