When Are Newborns at Risk for Hepatitis B?

A newborn baby with his mother
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While the disease caused by the hepatitis B virus has been known since the time of Hippocrates in the 5th century BCE, it wasn't until the 1960s and '70s that it was actually identified.

Today, even though most newborns are vaccinated against hepatitis B before they leave the nursery, we still have about 40 cases of perinatal hepatitis B each year—babies who get hepatitis B from their mother.

While extremely better than the pre-vaccine era, when there were over 3,500 cases each year, that means that there is still some work to be done. And it means that it is still very important to get vaccinated.

Why Infants Get Hepatitis B

Why do infants still get hepatitis B? Risks include:

  • Mothers who didn't get prenatal care and so weren't tested for hepatitis B
  • Newborns of HBsAg-positive mothers who don't get treated on time, within 12 hours of birth, often because of medical errors, such as not giving HBIG and the vaccine on time or at all or missing positive test results
  • Newborns of mothers with unknown hepatitis B test results who don't get treated on time (they should usually be treated as if they are positive since they could be)
  • Infants of HBsAg-positive mothers who don't complete their hepatitis B vaccination series

And then there are newborns born to highly viremic mothers, who might still get hepatitis B despite getting HBIG and the hepatitis B vaccine. Use of oral anti-HBV drugs, such as lamivudine, telbivudine, and tenofovir, can hopefully keep these babies from getting hepatitis B.

Hepatitis B viral load testing is typically done in the third trimester of pregnancy, so that maternal antiviral therapy can be started if is very high, helping identifying mothers who are highly viremic. Another risk for a baby getting hepatitis B might, therefore, be not having that test or antiviral treatment.

Take Steps to Prevent Hepatitis B

The hepatitis B virus:

  • Has infected 2 billion in the world
  • Has chronically infected more than 350 million people, including at least 2.2 million in the United States
  • Causes 50 million new infections each year worldwide
  • Is most likely to cause chronic infections in young children
  • Kills more than 600,000 people each year
  • Spreads from person to person through blood and body fluids
  • Can cause acute and chronic hepatitis (with jaundice), cirrhosis, and hepatocellular carcinomas (liver cancer)

Fortunately, especially since there is still no cure for these infections, hepatitis B is a now vaccine-preventable disease.

The first plasma-derived hepatitis B vaccine was approved in 1981 and was soon replaced by a recombinant, second-generation vaccine in 1986.

Although the vaccine was effective at preventing hepatitis B infections, the initial strategy of only targeting high-risk groups (selective vaccination) didn't work well. This was mostly because a lot of people didn't know they were high risk, especially if they were simply a household or sexual contact of someone else who was high risk, such as having multiple sexual partners or using intravenous drugs.

Even prenatal risk factor based screening (selective vaccination with screening) missed many pregnant women with chronic hepatitis B infections and the chance to stop their babies from getting hepatitis B.

That's likely why it wasn't until we switched to a universal childhood immunization program (1991) that we were able to see a dramatic decrease in hepatitis B infections in children. According to the CDC, the incidence of acute hepatitis B declined 96 percent in children and teens from 1990 to 2005.

Although some countries still do selective screening with vaccination, it is simply because they have such a low prevalence of hepatitis B carriers in their country that universal vaccination is simply not thought to be cost-effective. These include countries such as Denmark, Finland, Iceland, Japan, Norway, Sweden, and the United Kingdom.

The great majority of countries do universal vaccination instead, including some, like Ireland and the Netherlands that recently switched from selective screening.

Two hepatitis B vaccines, Recombivax HB and Engerix-B, are now available in both pediatric and adult formulations. They offer great protection (80 to 100 percent) against hepatitis B infections when given as a three-dose series.

Pediarix is a combination vaccine that contains the DTaP, hepatitis B (Engerix-B), and IPV vaccines in one shot.

Bottom Line

Hepatitis B is a vaccine-preventable disease that your children can avoid. Whether they are born in a hospital, birthing center, or at home, they should be vaccinated with a three-dose immunization series that begins soon after they are born.

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