or may not have symptoms and therefore never seek the attention of medical or public health officials. Rates of acute hepatitis B in the United States have declined by approximately 82% since 1991, which was when the routine vaccination of children was implemented and dramatically decreased rates of the disease particularly among children.
The likelihood of acute hepatitis B becoming chronic depends upon the age of infection. The younger a person is when infection occurs, the greater the their chance of developing chronic hepatitis B becomes. Approximately 90% of infected infants will develop chronic infection with the chance declining as the child ages. 25-50% of children infected between the ages 1 and 5 years will develop chronic hepatitis B. The risk drops to 6-10% if the person is infected after the age of 5. Worldwide, most people with chronic hepatitis B were infected at birth or during early childhood.
Most people infected with hepatitis B virus lack
symptoms and lead normal lives. In about 25% of cases, HBV can cause serious liver damage, including fibrosis and cirrhosis, usually over several years. In severe cases, hepatitis B can lead to liver- failure and death. There are also various treatments that can help slow or stop disease progression.
Hepatitis B infection is such a concern because the virus can routinely live outside the body for 7 days. As of 2011, 179 countries had incorporated hepatitis B vaccine as an integral part of their national infant immunization programs. Today, teenagers are routinely vaccinated against HBV, but infant vaccination is optional. The American Academy of Pediatrics recommends HBV vaccination for all infants. The hepatitis B vaccine series is paramount to your safety.
Transmission
HBV is transmitted by direct blood-to-blood contact. A major transmission route is sharing needles for injection-type drugs.
Needles used for tattooing and body piercing may also spread the virus. Transmission can happen when a small amount of hepatitis B-infected blood remains on an item after use and is transferred to another person who is using the same item. Sharing personal items such as razors, toothbrushes, and nail files are less likely, but is still considered a possible transmission route.
In the past, many people have contracted HBV through blood transfusions. A test for HBV in donated blood has been in use since 1972 and a test for HCV
11 The Basics
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101
