Not all pregnant women are universally screened for hepatitis B virus (HBV) in Ontario, even though this screening is recommended, and the majority of those who test positive do not receive follow-up testing or interventions, leading to infections of newborns, found new research in CMAJ (Canadian Medical Association Journal).
An estimated 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 recommends that countries such as Canada provide a first vaccine against HBV in newborns at birth. However, only three provinces and territories vaccinate at birth, five vaccinate starting at two months of age, and five provinces, including Ontario, vaccinate schoolchildren in grades six and seven. Complete province and territory information can be found here.
“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 the Toronto Centre for Liver Disease, University Health Network, and the University of Toronto. “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. That is why we should reconsider our current vaccination strategy in Ontario.”
To understand the uptake of prenatal HBV 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 years of age, 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 the Toronto 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 HBV during pregnancy. If the test is positive, they should receive follow-up to prevent spread and ensure they receive appropriate HPV care.
“Prenatal hepatitis B screening and hepatitis B burden among children, in Ontario: a descriptive study” was published October 26, 2020.