The Hepatitis B Vaccine
What is hepatitis B?
Hepatitis B is a serious disease that is caused by the hepatitis B virus (HBV) which usually exists in the blood and bodily fluids of the infected (or HBV+) person. The virus infects people of all ages and every year, about 200,000 people are newly infected in the United States. Of this 200,000, 90 percent eventually recover and clear the virus, but over 11,000 will have to be hospitalized and over 20,000 (10 percent) will become chronically (permanently) infected with the virus. About 1.25 million people in the United States have chronic HBV infection, and more than 4,000 people die each year from hepatitis B related liver disease. Before the introduction of the hepatitis B vaccine, over 30,000 children were infected annually, and it is estimated that about a third of our current chronic HBV infections are persons infected either as children or infants prior to the introduction of the hepatitis B vaccine. In fact, the younger a child is at the time of infection with HBV, the greater the likelihood that the child will become chronically infected and be at greater risk for liver disease as an adult.
What is the treatment for hepatitis B?
There is no known cure for hepatitis B. Thus, prevention is the best option to dealing with this disease. Currently, the only Food and Drug Administration (FDA)-approved medicines for treatment of hepatitis B are interferon alpha and lamivudine. Interferon alpha, which is administered via injections, often has side effects, some of which may be severe, and is usually used only for persons whose liver enzyme tests are abnormal. The FDA recently approved Lamivudine in December 1998 for the treatment of chronic hepatitis B in adults. This DNA polymerase inhibitor was originally used for treatment of HIV, and unlike interferon alpha, is available in oral form and appears to have fewer side effects. However, there is a significant risk of viral mutations leading to drug resistance thereby diminishing the drug’s effectiveness. Please consult a physician regarding the therapeutic benefits and side effects of any of these treatments.
What is the hepatitis B vaccine?
The hepatitis B vaccine has been available since 1982. The vaccines currently in use in the United States are made with recombinant DNA technology, and contain protein portions of HBV (usually parts of the outer protein or the surface antigen of HBV). Thus, the vaccines do not contain any live virus. The vaccine is administered intramuscularly in three doses usually given on a schedule of 0,1, and 6 months, but there can be flexibility in this schedule. More than 95 percent of children and adolescents and more than 90 percent of young, healthy adults develop adequate immunity following the recommended three doses. Persons who respond to the vaccine are protected from both acute hepatitis B infections as well as chronic infection.
Who should be vaccinated?
The Advisory Committee on Immunization Practices (ACIP) recommends hepatitis B vaccination for everyone 18 years of age and younger, and for adults over 18 years of age who are at risk for HBV infection, which include:
- Sexually active heterosexual adults with more than one sex partner in the prior 6 months, or have a history of sexually transmitted disease;
- Homosexual and bisexual men;
- Illicit injection drug users;
- Persons at occupational risk of infection;
- Hemodialysis patients;
- Household and sex contacts of persons with chronic HBV infection;
- Clients and staff of institutions for the developmentally disabled.
Why is vaccination recommended for all children as opposed to children living in families where there is the highest risk of HBV infection?
Routine vaccination of all children and adolescents is recommended because a major part of the disease burden of HBV is due to the large number of HBV infections that occur among children. As discussed earlier, a significant number of our chronic carriers of HBV were infected as children and if it were not for the vaccine, over 30,000 children would be infected annually. Most of these infections occur among children of mothers who are not infected with HBV and thus cannot be protected by perinatal hepatitis B prevention programs. Additionally, it is impossible to identify and selectively vaccinate only those children who would be at risk for HBV infection.
While it is true that most HBV infections occur in older adolescents and adults, it has been difficult to reduce the incidence of new HBV infections by selectively vaccinating older adolescents/adults in high-risk groups. In fact, over 30 percent of people infected with HBV have no idea where they might have got their infection! By vaccinating children for hepatitis B, they will now be protected against HBV infection when they become older adolescents and adults.
Is the hepatitis B vaccine safe?
Yes. The hepatitis B vaccines have been administered to more than 20 million people in the United States and more than 500 million people in the world. The most common side effects of vaccination are pain at the injection site (3 percent-29 percent) and/or a mild fever (1 percent-6 percent). However, these side effects are related to the injection event and not to the hepatitis B vaccine itself as persons receiving placebo injections also reported similar reactions.
What are possible serious side effects?
Serious side effects after administration of the hepatitis B vaccine are extremely rare. There have been some anecdotal reports of the association of hepatitis B vaccination with chronic illness such as autoimmune disorders. However, there have been no scientific data supporting these claims. Large-scale immunization exercises have been ongoing in many other countries and in the United States, and thus far there has been no association of hepatitis B vaccination with serious adverse events. No clear association has been demonstrated between hepatitis B vaccination and disorders such as Guillain-Barre syndrome, transverse myelitis, optic neuritis, and seizures. Even then, such alleged associations are still being studied to further ensure the safety of the vaccine. A recent study demonstrated that persons who developed rheumatoid arthritis following hepatitis B vaccination were actually genetically susceptible to rheumatoid arthritis, making it difficult to correlate the occurrence of rheumatoid arthritis with hepatitis B vaccination. Considering the large number of doses of HBV vaccine administered and the very low numbers of serious adverse reactions, it is possible that adverse reactions reported after hepatitis B vaccination may represent coincidence rather than causation.
Finally, as with any vaccination, the risk of anaphylaxis (hives, difficulty breathing, shock) is a real. There is an estimated incidence of about 1 anaphylactic reaction per 600,000 vaccine doses distributed. Thus, further administration of hepatitis B vaccine would be contraindicated (not recommended) for persons who have demonstrated a previous anaphylactic reaction following a previous dose of hepatitis B vaccine.
Any presumed risk of adverse side effects associated with the hepatitis B vaccine must be balanced with the expected 4,000 to 5,000 chronic HBV-related deaths and 30,000 childhood HBV infections that would occur in the absence of HBV immunization. Given the frequency and severity of hepatitis B infection, the benefits of vaccination far outweigh the known and potential risks.
What is the relationship between hepatitis B vaccination and multiple sclerosis (MS)?
Currently, there are NO scientific data that supports such an association. An expert panel convened by the World Health Organization (WHO) in September 1998 analyzed all available data on hepatitis B vaccine and concluded, "No evidence presented at this meeting indicates a need to change public health policies with respect to HBV immunization."
The actual cause of MS is still unknown but MS is believed to be an autoimmune disease in genetically susceptible persons where degradation of the myelin sheath that protects nerves in the central nervous system occurs. The initial associations between hepatitis B vaccination and MS were from case reports, not scientifically controlled studies. However, these case reports have been picked up by the news media, first in France, and now in the United States. It is more than likely that these MS case reports are purely coincidental to hepatitis B vaccination. However, to ensure continued safety of the vaccine, carefully controlled scientific studies are now underway.
Otherwise, there is no evidence that HBV vaccination causes MS or any other chronic disorder. In fact, negative evidence supporting the safety of the HBV vaccine is overwhelming. First, extensive clinical trials of the vaccine prior to its licensure did not document a single such association. Second, there have been hundreds of millions of people immunized worldwide that have not developed MS or any other autoimmune disease. Thus, if HBV vaccination does cause MS, it is an extremely rare event. Third, studies of MS patients have shown that stimulation of the immune system may lead to an exacerbation of the clinical disease. Thus, immunization, which will stimulate the immune system, may cause exacerbation of MS in those already suffering from the disease, and there have been some case reports of this. Even then, another well-controlled clinical trial has demonstrated that within the MS population, exacerbation of disease due to immunization does not happen, and if it did, could only happen in a very small minority of MS patients. However, NO evidence is available that suggests that HBV vaccination increases the MS rate in healthy persons. In order to establish causation, carefully controlled scientific studies such as the ones currently ongoing are needed.
There are currently at least 6 research projects underway to examine the relationship between hepatitis B vaccination and MS, if any exists. Results from most of these studies will begin to emerge in 1999, and it is reported that some preliminary data from some of these studies were available to the September 1998 WHO expert panel. Hopefully these results will clarify once and for all the recent unproven hypotheses that have caused significant public concern by suggesting an association of MS with HBV immunization.
How is vaccine safety monitored?
The Vaccine Adverse Event Reporting System ensures the safety of vaccines distributed in the United States. Health care professionals or vaccine manufacturers usually submit these reports, but anyone can do submit a VAERS report if they wish. Persons wishing to report a possible health effect related to a vaccine should notify their health care provider and can also call 1-800-822-7967.
Are there more serious reactions to HBV vaccine than there are cases of hepatitis B in children under 14 years of age?
No. This is a recent allegation and data from the VAERS database was used in its support. It has now been addressed by Bruce Gellin, MD, Director of the National Network for Immunization Information, a special project of the Infectious Diseases Society of America and the Pediatric Infectious Diseases Society. Briefly, it is not possible to determine the number of adverse reactions simply by examining the number of VAERS reports associated with that vaccine. This is because the VAERS database is used to examine overall trends and unusual occurrences for further study, not to quantify the numbers of case reports. VAERS will therefore accept ALL reports health effects that follow vaccination, regardless of whether they are correlated to the vaccine or not. Thus, many of the VAERS reports have a coincidental rather than causal relationship with vaccination. Other cases may be reported more than once such as when a health care provider, a parent, and the vaccine manufacturer, all file reports for the same effect, or if the child has several effects with one vaccine and a report is filed for each side effect.
In fact, a published review of the VAERS data between 1991 through 1994 actually showed that there were no unexpected adverse events in over 12 million doses of HBV vaccine administered to infants. Additionally, data from the National Center for Health Statistics show no increase in reports of infant deaths since 1991, the year routine hepatitis B vaccination was introduced.
Where can I find more information on hepatitis B?