Hepatitis B shots should be offered for infants in all Canadian provinces and other countries, say researchers who reviewed evidence on immunization.

In a review article published in Tuesday's issue of the Canadian Medical Association Journal, Dr. Christopher Mackie, an assistant professor in the department of clinical epidemiology and biostatistics at McMaster University in Hamilton, and his colleagues said research suggests about one-third of chronic hepatitis B infections are picked up during infancy and early childhood.

A baby infected with the hepatitis B virus is about 10 times more likely than an adult to develop a chronic hepatitis B infection, which can can lead to liver cancer or liver failure and, in some cases, death.

Most provinces started universal hepatitis B immunization programs for adolescents in the 1990s, but only British Columbia, New Brunswick and Prince Edward Island offer the vaccines for infants.

Vaccinating teenagers offers protection against the infection, but studies suggest that booster shots in adolescence aren't needed when people are immunized as babies.

In 2001, B.C. became the only province to offer the vaccine to both age groups.

After years of having more cases of hepatitis B infections than other provinces, B.C. now has an annual incidence that is consistently below the national average, with no cases reported in the past four years, the researchers said.

"The few jurisdictions that continue to offer universal immunization in adolescence rather than infancy should consider changing to an infant program," the team concluded.

Less cost, pain

Targeting the program toward infants would help maximize protection for the whole population, they said.

"Although we have not completed a costing analysis, switching from the adolescent program to an infant campaign would actually save costs, time and pain as well as prevent more illness," Mackie said in an email.

"An infant campaign could be delivered as part of the standard series of vaccines."

Also, a new form of the vaccine is available for infants that combines six immunizations in one. Using the combination would eliminate the need for expensive school-based programs while reducing the number of pokes, he added.

Worldwide, 98 per cent of universal hepatitis B immunization programs are offered in infancy.

To track and evaluate the effectiveness of such a campaign, the researchers recommended a national immunization registry.

The standard hepatitis B vaccine has been used safely for more than 30 years.

Hepatitis B can be passed on during birth, sexual activity or through open cuts.