Viral Hepatitis in Hawai‘i – Differing Perspectives
V. The Future of Hepatitis in Hawai‘i
B. Hepatitis and Impact of Immunization:
Neal Palafox MD
pp.15-16
Two different perspectives about hepatitis B vaccination programs are presented. The first highlights the data and epidemiology of hepatitis B in US associated Pacific nations, and the second addresses implementation of childhood vaccinations in the United States specific to Hawai‘i.
Hepatitis B in the US Associated Pacific
The Compact of Free Association (COFA) defines the relationship that three sovereign nations, the Federated States of Micronesia (which include Chuuk, Kosrae, Pohnpei, and Yap), the Republic of the Marshall Islands, and the Republic of Palau, have entered into as associated entities of the United States. In exchange for certain defense rights, the United States provides guaranteed financial assistance to the COFA nations, representing a total of 475,000 people.
Health outcomes such as increased infant mortality and reduced longevity in these nations are directly related to amount of healthcare spending by the US government, where approximately $5,700 was spent per capita in the United States, while nations such as Chuuk and Pohnpei received only $80 and $117 per person per year respectively in 2006 (Figure 2).31-32
In addition, there are an estimated 14,500 COFA Micronesians living in Hawai‘i with a growth rate of 6.2% annually. Of those individuals, an estimated 18% are hepatitis B surface antigen positive. Two-thirds of the homeless population in Hawai‘i are Micronesians and may be at increased risk for HBV infection due to poor hygiene, skin injuries, and related lifestyle components. As such, there is a vested interest in caring for this population both in Hawai‘i and within their own nations. As shown in Table 5, despite introduction of the HBV vaccine in the late 1980s, the percentage of individuals in Chuuk with positive HBV markers prior to 1985 was 80%, and in 2007 the percentage was 76%, with chronic rates of infection actually increasing in both Chuuk and Pohnpei.33-35
Although the rates show decline in other nations, the overall infection and exposure rates are extremely high. In the Marshall Islands, 4.6% of total deaths reported in 2005 were due to chronic liver disease.36 Similarly, in Pohnpei and Palau, chronic liver disease represented 7% of the total deaths occurring in those nations.37
When the hepatitis B vaccine is given properly, it is 95% effective in preventing chronic infections. Hepatitis B was added to the routine childhood immunization schedule in most Pacific Island nations in the late 1980s, and multiple seroprevalence surveys were conducted to measure the impact of introduction of the vaccination. In Chuuk it was shown that prior to the immunization program in 1988 15% of two year old children had chronic hepatitis B infection, but that by 1992 the number was down to 3%, demonstrating that the vaccination programs are indeed capable of being effective. However, the biggest predictor of HBV in these areas is vertical transmission at birth from mother to infant, and vaccination within 24 hours of birth is an important factor in prevention. In Chuuk in 2000, only 61% of infants received a dose at birth, with similar numbers reported in Pohnpei and the Marshall Islands. It was reported that none of the chronically infected children in Chuuk received a birth dose of the vaccine, and none of the infected children received all three doses of the vaccine on schedule. Because the hepatitis B vaccine needs to be implemented at birth for maximum efficacy, accessibility and availability of vaccines to the remote outer islands needs to be addressed and improved. A recent advance includes the introduction of the ‘Uniject’ system which provides for the stable storage of the hepatitis B vaccine at up to 90ºF for up to 30 days without losing immunogenic properties.
In contrast to HBV transmission in the United States where adolescents and adults more commonly test positive, the primary populations infected with HBV from Pacific nations are infants and young children. This is due primarily to both perinatal and horizontal transmission (child to child or among family members), as HBV is stable in the environment for up to seven days and is capable of transmitting via contaminated objects, particularly in crowded communities and shared households. Vastly improved systems of diagnosis, treatment, and management need to be put into place both in Hawai‘i and within the COFA nations, with targets of immunization programs being infants and children since age of infection is biggest predictor of chronic HBV infection. Primary goals for improving HBV infection rates in these areas include expanded education programs, proper prenatal care and testing, increased availability of vaccines particularly for areas outside of the hospital setting, and routine vaccination of children within 24 hours of birth up to age five.
Implementation of Hepatitis B Childhood Vaccinations
Since 1991 a key strategy to eliminate hepatitis B transmission in the United States was to administer the first dose of the vaccine at birth, preferably within 12 hours to ensure that the mother does not leave before the infant has a chance to get immunized. Implementation of the hepatitis B birth dose provides early protection to infants at risk for infection after the perinatal period without knowing HBV status of birth mother. This leads to an overall higher rate of on time completion of the HBV vaccine series. Through the immunization program, the incidence of HBV among children and adolescents in the United States declined 89% between 1990 and 2002. However, parents often have philosophical or religious objections to vaccines or have read conflicting media reports about vaccine safety and child development, and raise questions for the practitioner to address.
Parents commonly question whether their children should be vaccinated against hepatitis B when they don’t feel as if their children or families are exposed to any of the risk factors. These concerns can be addressed by emphasizing the importance of getting vaccinated despite the absence of obvious risk factors in that 16-30% of all hepatitis B cases have no known source of infection. Unvaccinated children in families with no known risk are still at some risk for infection through normal play activities, and teenagers have an increased risk of exposure when they become sexually active. The most common source of infection is from mothers who may not know that they are hepatitis B infected. Despite being a vaccine-preventable disease, HBV is still responsible for death in 2% of cases.38
There are also concerns that children are too young to receive the large number of shots they are given as infants through early childhood. It is true that 20 years ago there were seven routine vaccines given compared to 11 routine vaccines given now, with some 20 total injections by the time a child is two years old, yet the number of total vaccine proteins and polysaccharides is less than it was in the past. Young infants are capable of responding antigenically to about 100,000 different organisms at one time. There was some confusion surrounding whether to administer both the birth dose of hepatitis B vaccine as well as the combination shot, Pediarix, which combines the DTAP, polio, and hepatitis B vaccines. In some cases practitioners were deferring the birth shot in favor of the combination shot administered at two months of age, however, it is advised to not eliminate the birth shot, and studies have shown that administration of the combination shot does not constitute an extra dose nor does it cause an increase in side effects. In addition to childhood screening, all pregnant women should have hepatitis B surface antigen (HBsAg) testing so that immunoprophylaxis can be given to infants with HBsAg positive mothers. Results of prenatal testing should be both given to the mother as well as communicated to the facility where the mother is expected to give birth.
The relatively new hepatitis A vaccine is an added immunization at 12 months and 18 months, although not all health plans cover it. In 2005, 4,488 cases of hepatitis A were reported to the CDC, although there were an estimated 42,000 new cases overall. The CDC recommends individuals ages one year and older should receive the HAV vaccine as a routine vaccination and that this will likely be added to the vaccination requirements for entry into school.
Vaccinations are the cornerstone for prevention of disease. Use of information and educational strategies can enable parents to follow through and ensure completion of their child’s vaccines.
