Despite being recommended, not all pregnant women are universally screened for hepatitis B virus (HBV) in Ontario, and the majority of those who test positive do not receive follow-up testing or interventions, leading to infections of newborns, found new UHN-led research, published Oct. 26 in the Canadian Medical Association Journal.
More than 257 million people worldwide are chronically infected with HBV, which is a risk for cirrhosis of the liver and liver cancer.
The World Health Organization (WHO) recommends that all infants receive a first vaccine against hepatitis B at birth. However, only three provinces vaccinate at birth; five vaccinate at two months of age; and five provinces – including Ontario – vaccinate children in Grades 6 and 7.
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"One rationale for not vaccinating at birth is that universal prenatal screening and related interventions prevent transmission from mother to baby," explains Dr. Jordan Feld, a liver specialist at UHN's Toronto Centre for Liver Disease.
"However, our study shows that screening is imperfect, and that children born in Canada are becoming infected with hepatitis B before getting vaccinated as teenagers," says Dr. Feld, who is also Co-Director of the Schwartz Reisman Liver Research Centre and R. Phelan Chair in Translational Liver Research. "That is why we should reconsider our current vaccination strategy in Ontario."
To understand the uptake of prenatal hepatitis B screening in Ontario and determine the number of HBV infections in children before adolescent vaccination in the province, researchers analyzed data from ICES, Public Health Ontario and Better Outcomes & Registry Network (BORN) Ontario, between 2003 and 2013.
In children under 12, 139 Canadian-born children tested positive for HBV. This represents a minimum number of infections in Canadian-born children because most children are never tested, and the infection has few or no symptoms early in life.
These infections could have been prevented by vaccination at birth. Once the infection is established in a newborn, it is usually lifelong, requiring close follow-up and puts people at risk of complications.
"Canadian guidelines recommend changes to provincial hepatitis B immunization strategies if women are not screened universally and/or children become infected. We have met this threshold, and a change is needed," explains Dr. Mia Biondi, a primary care nurse practitioner in the community, and researcher at UHN'sToronto Centre for Liver Disease.
"Infant hepatitis B vaccination could be seamlessly integrated into primary care, in line with well-baby visits and other vaccinations. It's a simple solution."
The authors recommend that Ontario move to HBV vaccination at birth and improve existing systems to ensure that all women are screened for hepatitis B during pregnancy. If the test is positive, they should receive follow-up to prevent spread and ensure they receive appropriate HBV care.