Chronic hepatitis B infection in adolescents vaccinated at birth: An alarm bell in favor of the need for a booster?

Abstract

et al. 1 reported that a significant proportion of adolescents born to hepatitis B surface antigen (HBsAg)-positive mothers, who had postnatal hepatitis B immune globulin (HBIG) and hepatitis B vaccine, lost immune memory and developed a HBsAg carrier state. Having maternal hepatitis B e antigen (HBeAg) positivity was the most important determinant for developing chronic hepatitis B.Vaccination has proved to be highly effective in preventing and controlling hepatitis B, carrier rate, and hepatitis B virus (HBV)-related mortality worldwide. Long-term protection studies indicate that vaccine-induced anti-HBs concentrations decline over time, with antibody (Ab) levels falling below the protective threshold (10 mIU/mL) in one third to one half of vaccinees 10-20 years later; however, immunological memory usually persists. 2,3 This is because Ab maintenance after vaccination depends on the number of longlived plasma cells, whereas booster response is a function of memory B cells. Evidence indicates that memory B cells effectively respond to antigen challenge even when Ab falls below the protective level. 4 Thus, booster doses are not needed in immunocompetent individuals to maintain long-term protection.However, failure to develop postbooster anamnestic response has been reported, raising concern that immune memory may wane during the second decade postvaccination. 5,6 In his study, Wu et al. show that 15% of adolescents born to HBsAg/HBeAgpositive mothers who received primary infantile vaccination developed chronic HBV infection. In addition, one sixth of vaccinees were unable to respond to booster vaccination, having lost immunological memory.Individuals who lost immunological memory may become vulnerable to HBV infection, especially in highly endemic regionssuch as some Asiatic countries-where HBsAg carriers are often positive for HBeAg, then highly infectious. Thus, need for a booster in this setting, where risk of acquiring infection and becoming chronic is high, should be considered. If this were the policy, booster should be given before loss of immunological memory occurs.

Efficacy of Neonatal HBV Vaccination on Liver Cancer and Other Liver Diseases over 30-Year Follow-up of the Qidong Hepatitis B Intervention Study: A Cluster Randomized Controlled Trial

“…In several recent studies, researchers reported that about one-quarter of neonatal vaccine recipients had lost their immune memory to the HBV vaccines when entering young adulthood [37] , [38] . Because young adults may engage in risky behaviors that potentiate horizontal transmission of HBV as they become sexually active [31] , the booster policy was recently recommended for consideration in highly endemic regions, such as some Asian countries [39] . Our current study showed that a booster at age 10–14 years might improve the neonatal vaccinee's immunological memory and potentially prevent HBV horizontal infection in young adults.…”

Characteristics of immune memory 10–15 years after primary hepatitis B vaccination

“…These observations led to the conclusion that protection against clinically significant breakthrough infection and chronic carriage is long-term rendering booster doses unnecessary [1,[9][10][11]. However, over the past years, a number of studies have reported about waning immunity over time by showing a loss of the ability to respond to booster vaccination [12][13][14][15][16]. A recent meta-analysis has shown that, 20 years after infant vaccination, about 40% of individuals who had lost protecting antibodies did not respond to booster vaccination [17].…”

Hexavalent vaccines for immunization in paediatric age

“…Because Hexavac HBsAg content was only 5 μg, the possibility that children who received this vaccine could be at higher risk of losing immune memory and developing infections of HBV in adolescence or in adulthood cannot be excluded. On the other hand, recent studies showed that immune memory may diminish during the second decade post‐vaccination (particularly in children vaccinated at birth), suggesting the need for a booster dose during adolescence . Wu et al showed that 15% of adolescents born to HBsAg/HBeAg‐positive mothers who received primary infantile vaccination developed chronic HBV infection.…”