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Terence T Lao

Terence T Lao

Chinese University of Hong Kong, Hong Kong

Title: Immune persistence after hepatitis B vaccination in infancy: Fact or fancy?

Biography

Biography: Terence T Lao

Abstract

The hepatitis B vaccine has been in use for more than three decades and its efficacy has been widely reported. In Hong Kong, excellent vaccine coverage through an efficient public health care system, together with supplemental programs and easy availability of the vaccine, meant that most young pregnant women, and university students at entrance, should have been protected. Yet data from Hong Kong has not indicated a progressive decline in maternal carriage of hepatitis B virus (HBV). On the other hand, significant increase in the prevalence of HBV infection and a positive correlation with age has been found in students at university entrance, and in young mothers aged 25 years or less. This paradoxical phenomenon is most likely related to clinical vaccine failure. A number of factors are involved, such as the failure to respond to a primary series of hepatitis B vaccination in infancy, the waning of antibody titres with age, and loss of anamnestic response in a significant portion of the vaccines. We have shown that up to one in five of children who had received a full course of hepatitis B vaccination in infancy failed to develop an immune response. Furthermore, among adolescents and young adults covered by the universal vaccination program in infancy, waning of antibody titres to non-protective levels and loss of anamnestic response are not uncommon by the time of university entrance, despite a low incidence of HBV infection. Taken together, there is concern for the purported life-long protection conferred by hepatitis B vaccination in infancy. The duration of protection should be re-examined in further studies and remedial measures considered if long term protection is found to be insufficient. Otherwise, the efforts to control HBV infection, especially in high endemicity regions, with universal vaccination in infancy would be rendered futile.

Publications:

TT Lao, JSM Mak, TC Li. Hepatitis B virus infection status and infertility causes in couples seeking fertility treatment—Indicator of impaired immune response? American Journal of Reproductive Immunology 2017 (in press).

TT Lao. Immune persistence after hepatitis B vaccination in infancy–Fact or fancy? Human Vaccines & Immunotherapeutics 2016;12 (5), 1172-1176.

TT Lao, MK Chung, TKW Cheung, LW Law. Antenatal hepatitis B and increased risk of gestational diabetes mellitus–Implications for obstetric care. Journal of Infection 2016;72 (5), 625-626.

TT Lao, KL Cheung, V Wong. Hepatitis B vaccine response among infants born to hepatitis B surface antigen-positive women.Vaccine 2015;33 (1), 15-16.

TT Lao, DS Sahota, LW Law, YKY Cheng, TY Leung. Age-specific prevalence of hepatitis B virus infection in young pregnant women, Hong Kong Special Administrative Region of China. Bulletin of the World Health Organization 2014;92 (11), 782-789.

TT Lao, DS Sahota, MK Chung, TKW Cheung, YKY Cheng, TY Leung. Maternal ABO and rhesus blood group phenotypes and hepatitis B surface antigen carriage. Journal of Viral Hepatitis 2014;21 (11), 818-823.

PKS Chan, KLK Ngai, TT Lao, MCS Wong, T Cheung, ACM Yeung, et al. Response to booster doses of hepatitis B vaccine among young adults who had received neonatal vaccination. PloS One 2014;9 (9), e107163.

TT Lao, DS Sahota, SSH Suen, PKS Chan, TY Leung. Impact of neonatal hepatitis B vaccination programme on age-specific prevalence of hepatitis B infection in teenage mothers in Hong Kong. Epidemiology and Infection 2013;141 (10), 2131-2136.

TT Lao, DS Sahota, YKY Cheng, LW Law, TY Leung. Maternal hepatitis B surface antigen status and incidence of pre‐eclampsia. Journal of Viral Hepatitis 2013;20 (5), 343-349.

SSH Suen, TT Lao, OK Chan, TK Lau, TY Leung, PKS Chan. Relationship between age and prevalence of hepatitis B infection in first-year university students in Hong Kong. Infection 2013;41 (2), 529-535.