On this page
Every unit of donated blood in a modern blood bank is tested for hepatitis B. The test exists because a geneticist went looking for something else entirely. Baruch Blumberg was cataloguing how blood proteins differ between peoples, and a strange line on a gel led him to a virus that infects hundreds of millions of people. This post covers how that happened, the numbers in his story, and what it means for your biology chapter.
Who was Baruch Blumberg?
His Nobel facts page says he was born on 28 July 1925 in New York and died on 5 April 2011. He shared the 1976 Nobel Prize in Physiology or Medicine with D. Carleton Gajdusek "for their discoveries concerning new mechanisms for the origin and dissemination of infectious diseases".
His Nobel biography shows an unusual path. He took an undergraduate degree in physics, started graduate work in mathematics, then switched to medicine. As a student he spent months in Surinam, where his first research paper was on how differently people responded to *Wuchereria bancrofti*, the filarial worm. He later earned a PhD in biochemistry at Oxford and, from 1957, studied inherited variation in blood proteins at the US National Institutes of Health.
How did a blood protein study find a virus?
Blumberg's method was to take blood serum from people who had received many transfusions. Such patients often make antibodies against proteins in donors' blood that differ from their own. He tested their serum against a panel of serum samples from around the world and looked for lines where antibody met antigen in a gel.
In his Nobel lecture he describes what happened in 1963. Serum from a haemophilia patient in New York gave a new kind of line. Most antibodies they had studied reacted with about 50 to 90% of the panel. This one reacted with only one of 24 sera, and that sample came from an Aboriginal Australian. They named the unknown substance Australia antigen, written Au. The first report appeared in JAMA in 1965.
How did they link Au to hepatitis?
The lecture tells two turning points. In 1966 a patient at their clinical unit who had tested negative for Au tested positive on a second test. Liver tests showed he had developed hepatitis in between. Then, in April 1967, a technician in the lab, Barbara Werner, felt unwell, tested her own serum and found Au. She went on to develop hepatitis and recovered.
By the end of 1966 the team had found Au in many patients with acute viral hepatitis. Their papers were at first met with doubt; one was rejected because other "candidate viruses" for hepatitis had come and gone. The 1976 Nobel press release explains what was settled later: Australia antigen, now called HBsAg (hepatitis B surface antigen), is the outer coat of the hepatitis B virus.
Worked example: why one in 24 stood out
Typical antibody: reacts with 50% to 90% of panel sera, so 12 to 22 of 24 samples (0.5 × 24 = 12; 0.9 × 24 = 21.6).
The new antibody: 1 of 24 = 0.042, or about 4%.
What that means: a protein found in most people would light up most of the panel. A reaction this rare suggested something present in only a few people, such as an infection carried by some and not others.
How did the discovery lead to a vaccine?
The lecture explains the idea. Many carriers had large amounts of HBsAg in their blood without being ill. Blumberg and Irving Millman proposed purifying that surface antigen from carriers' blood and using it as a vaccine, and filed a patent application in October 1969. Today's vaccines make the same surface protein without human blood: the NCERT Class 12 chapter Human Health and Disease gives "hepatitis B vaccine produced from yeast" as its example of a recombinant vaccine.
Why does hepatitis B still matter?
The WHO hepatitis B fact sheet estimates that 240 million people were living with chronic hepatitis B in 2024 and that it caused 1.1 million deaths, mostly from cirrhosis and liver cancer. Only 65 million knew they were infected: 65 / 240 = 0.27, or 27%.
Age matters a great deal. WHO says infection in adulthood becomes chronic in fewer than 5% of cases, but infection in infancy or early childhood does so in about 95%. That is why the vaccine is given soon after birth.
What can a student take from Blumberg's way of working?
Breadth pays off. Physics, mathematics, medicine and biochemistry all fed his approach to population data.
Follow the data across fields. He set out to study genetics and ended up in virology.
Let predictions be tested. The Au-negative patient who turned positive was a prediction checked by a liver test.
To connect antigens, antibodies and vaccines in one picture, the Fermi Concept Library covers every concept in biology, each with its own lesson and its place in the map. For a disease Blumberg first studied as a student, see our post on Patrick Manson and filarial worms.
Try it now: write two sentences explaining why a recombinant hepatitis B vaccine cannot give someone hepatitis B.
