Hepatitis B

Hepatitis B causes liver cancer!

The hepati­tis B vac­cine was the first  vac­cine to be use­ful in pre­vent­ing can­cer. It is given to new­borns to keep them from get­ting a chron­ic infec­tion with the hepati­tis B virus (HBV), which can lead to liv­er can­cer. It is par­tic­u­lar­ly impor­tant to vac­ci­nate infants again­st hepati­tis B. They are the peo­ple who are most like­ly to get a per­sis­tent HBV infec­tion.

Hepatitis B virus causes liver cancer in children
Hepati­tis B virus caus­es a chron­ic infec­tion that can lead to liv­er can­cer. Babies are most at risk.

The word hepati­tis means inflam­ma­tion of the liv­er. Sev­er­al unre­lat­ed virus­es can cause hepati­tis. By the mid 20th cen­tu­ry, it was obvi­ous that one kind of viral hepati­tis could be spread by unclean water or con­t­a­m­i­nat­ed food or casu­al per­son-to-per­son con­tact. It was called infec­tious hepati­tis. It is now called hepati­tis A, and it is due to the hepati­tis A virus HAV. Hepati­tis A caus­es a seri­ous but short-term infec­tion. Anoth­er kind of viral hepati­tis is much hard­er to catch. It was spread by blood-to-blood con­tact, such as by blood trans­fu­sions or through the reuse of hypo­der­mic needles, tat­too needles, or acupunc­ture needles. It was called serum hepati­tis. Today, we call it hepati­tis B.

Many  peo­ple with chron­ic hepati­tis B infec­tion have no idea that they are infect­ed. In this lec­ture, Dr. Stephanie Chao tells of a young doc­tor who had prob­a­bly caught hepati­tis B in child­hood. He died of liv­er can­cer at age 30. She stress­es that 90% of the peo­ple who catch hepati­tis B in infan­cy remain chron­i­cal­ly infect­ed for life. That’s why it’s so impor­tant to vac­ci­nate new­borns again­st hepati­tis B:

For­tu­nate­ly, we now have a high­ly effec­tive and remark­ably safe vac­cine for pre­vent­ing hepati­tis B infec­tion. To make this vac­cine, sci­en­tists found the gene for a pro­tein found on the sur­face of the hepati­tis B virus. They put this gene into a com­mon baker’s yeast. The­se trans­genic yeast then make large amounts of the viral pro­tein, which is refined and made into a vac­cine. Since this recom­bi­nant vac­cine has nev­er had any con­tact with actu­al hepati­tis B virus­es, there is no chance what­so­ev­er that a per­son could catch hepati­tis B from the vac­cine.

Many peo­ple think that hepati­tis B is only a sex­u­al­ly trans­mit­ted infec­tion. Although hepati­tis B can be spread through sex­u­al con­tact, it can be spread in oth­er ways as well. A new­born baby can catch hepati­tis B from his or her moth­er, either dur­ing birth or through breast­feed­ing. Hepati­tis B can also be spread by oth­er close con­tact between peo­ple, such as by peo­ple shar­ing a razor. It can also be spread in a preschool if an infect­ed tod­dler bites anoth­er child. It is par­tic­u­lar­ly impor­tant to pre­vent babies from being infect­ed by hepati­tis B. Babies and young chil­dren are the peo­ple who are most like­ly to go on to have a chron­ic hepati­tis B infec­tion. The­se chron­ic car­ri­ers of hepati­tis B can spread the dis­ease to oth­er peo­ple, and they are at high risk of liv­er can­cer. That’s why it is so impor­tant to vac­ci­nate babies again­st hepati­tis B.

Hepati­tis B kills. It kills a few peo­ple right away, by caus­ing a sev­ere case of liv­er inflam­ma­tion. It kills oth­er peo­ple slow­ly, by dam­ag­ing the liv­er or caus­ing liv­er can­cer. The hepati­tis B vac­cine will play an essen­tial role in erad­i­cat­ing hepati­tis B. In 1984, Tai­wan start­ed vac­ci­nat­ing infants again­st hepati­tis B. Since then, the num­ber of chil­dren with chron­ic hepati­tis B virus infec­tion has dropped by 85%, from rough­ly 15% of chil­dren to less than 1% of chil­dren. At the same time, the num­ber of cas­es of liv­er can­cer in chil­dren also decreased.