(Quebec) At the time the vaccine is not always consensus, one against hepatitis B, introduced in Quebec in 1983, proved its worth. Between 1990 and 2013, the incidence of the disease decreased by 97%, according to a recent study by the University Laval and the National Public Health Institute of Quebec (INSPQ).
“It’s very reassuring to see the current image,” says Gaston De Serres, medical epidemiologist at the INSPQ and study leader. “This is, I believe, a good example for which vaccination was highly effective.”
Published last June in BMC Infectious Diseases, the study shows that since 1990, the incidence of hepatitis B in Quebec increased from 15.0 to 0 by 100000personnes 20A in 29years, age group that was previously particularly affected by the disease, from 3.2 to 0 in 10-19 years, and 0.6 to 0 in 9 years old. This means that hepatitis B affects more practically Quebecers who received the vaccine in childhood.
Note, however, that the disease is not eradicated so far, it is not nearly so. “We still have several years before reaching zero,” says Dr. De Serres. “It’s complicated to eradicate [the disease], because Chronic carriers remain infectious all their life,” and there is no medicine to cure, he says.
Hepatitis B is a viral infection that attacks the liver. The vast majority of infected people, many of whom are asymptomatic, eliminate the virus through their own defense system. But in 5% of cases, the disease progresses to chronic infection. And although they are not constantly symptomatic, they carry the virus remain infectious throughout their lives.
Chronic infection increases the risk of cirrhosis and liver cancer. Dr. De Serres also states that hepatitis B is “one of the biggest causes of liver cancer in the world.”
Fortunately, the number of new chronic infections decreased by 66% in Quebec since the establishment of the Quebec immunization program.
The fulminant hepatitis, a rare and fatal complication of hepatitis B, which can occur in the acute phase (when the patient is symptomatic), in turn causing complete destruction of liver cells.
The Quebec immunization program against hepatitis B began in 1983 when were targeted high-risk individuals from contracting the disease. This was followed a few years later, systematic screening in pregnant women to prevent the disease being passed at birth.
“We realized that this strategy [target individuals at high risk] had no real impact,” said Gaston De Serres. In 1994, Quebec has therefore turned to universal vaccination in fourth grade. A strategy that allows today to vaccinate 85% of Quebec students against hepatitis B.
In this regard, Dr. De Serres says that even 15% of unvaccinated young are protected by “herd immunity” effect by which Quebecers vaccinated reduce the risk of infection in non-vaccinated decreasing the incidence of disease.