Evaluation of the response to a booster dose of hepatitis B vaccine in previously immunized healthcare workers
Introduction
Healthcare workers (HCW) are at increased risk of hepatitis B virus (HBV) infection, primarily from occupational exposure to infectious body fluids from persons with chronic infection [1], [2]. In the USA, it is estimated that over one million persons are chronically infected with HBV [3] and these persons represent an ongoing risk of infection to HCW. Safe and effective vaccines to prevent HBV infection were licensed in 1981 and have been commercially available since 1982 [4]. In 1982, it was recommended that HCW at risk of occupational exposure to HBV be vaccinated [5]. Given this recommendation and a mandate for employers to offer vaccination to this at-risk group [6], the number of HCW who are HBV-vaccinated has increased [7], [8]. However, the absolute duration of protection from immunization is unknown.
Many HCW may have received their primary hepatitis B vaccine series over 10 yr ago. Studies of long-term persistence of antibody indicate that adults who responded to the initial vaccine series may lose measurable antibody to hepatitis B surface antigen (anti-HBs) within 10 yr of immunization [9]. However, follow-up studies of immunized adults and children indicate that a single 3-dose vaccination series prevents HBV infection for up to 15 yr, including after loss of detectable antibody [10].
We conducted a randomized comparison trial to determine how HCW who previously responded to hepatitis B immunization, but subsequently had undetectable or low anti-HBs levels, would respond to a 2.5 or 10 μg booster dose of hepatitis B vaccine.
Section snippets
Method
The trial was conducted (1994–1995) at the Alaska Native Medical Center (ANMC), a tertiary care hospital located in Anchorage, Alaska, USA. The Alaska Area Native Health Service and Indian Health Service Institutional Review Boards approved the trial and participants granted informed consent.
Potential trial participants were identified through a comprehensive review of ANMC HCW medical records. Persons’ recruited were those evidencing (1) previous administration, as an adult, of 3 doses of
Results
Of the 115 participants who met the initial entry criteria, 48 (42%) were excluded as their baseline anti-HBs levels were >50 mIU/ml, 8 (7%) were lost to enrollment, 1 (<1%) only completed the first follow-up blood draw, and 58 (50%) completed all follow-up blood draws. Fig. 1 further illustrates number of participants randomized and followed-up by baseline anti-HBs level and booster dose administered. Demographic characteristics of participants (n=59) include: female, 39 (66%); Alaska Native,
Discussion
Our trial demonstrated that adults with undetectable or low anti-HBs level, 3 to 13 yr after receiving the 3-dose hepatitis B vaccine series, responded to a booster dose of vaccine. Fourteen days after either a low or high booster dose of vaccine antigen, nearly all participants had levels of antibody that ranged from 10 to >100 mIU/ml, indicating this was an anamnestic response to HBsAg.
The higher booster dose of vaccine resulted in a generally higher anti-HBs response when compared to the
Acknowledgements
For their contribution to this work the following are acknowledged: Leslie Fox-Leyva, Mary Snowball and Harvey Tanttila. Use of brand names is for identification purposes only and does not imply endorsement by the US Public Health Service or the US Department of Health and Human Services.
References (15)
The risk of hepatitis B infection among health professionals in the United States: a review
Am J Med Sci
(1984)- et al.
Vaccine induced immunologic memory for hepatitis B surface antigen: implications for policy on booster vaccination
Vaccine
(1996) Patients, needles, and healthcare workers: understanding the epidemiology, pathophysiology, and transmission of the human immunodeficiency virus, hepatitis B and C, and cytomegalovirus
J Intravenous Nursing
(1995)- Centers for Disease Control and Prevention, Viral Hepatitis B-Fact Sheet. Available at...
- et al.
The prevention of hepatitis B with vaccine. Report of the centers for disease control multi-center efficacy trial among homosexual men
Ann Int Med
(1982) - Centers for disease control and prevention. Recommendation of the immunization practices advisory committee inactivated...
- Occupational safety and health administration, US department of labor. Final rule on occupational exposure to...
Cited by (41)
Significance of anti-HBc alone serological status in clinical practice
2017, The Lancet Gastroenterology and HepatologyCitation Excerpt :Of note, anti-HBs tends to become undetectable relatively early, so anti-HBc alone is typically a recovered infection with undetectable anti-HBs. Also, HBsAg tends to decline over a much longer period of time but can become undetectable, leaving anti-HBc as the only marker of chronic infection, although HBsAg-specific T cell immune responses can still play an important role in protecting against HBV infection and replication.122,123 In both situations, sensitive detection of HBV DNA is crucial to diagnosis.
Hepatitis B immunity in teenagers vaccinated as infants: An Italian 17-year follow-up study
2014, Clinical Microbiology and InfectionCitation Excerpt :The fact that 10 of these vaccinees, despite having anti-HBs below protective levels (seven with anti-HBs <10 mIU/mL and three with undetectable antibody), showed a strong anamnestic response in the absence of serological signs of HBV breakthrough infections, suggests that cellular immunity lasts much longer than humoral immunity. Similar findings were reported in Alaska and in the Czech Republic, where 8.2% of 1530 vaccinees followed for 10 years after immunization and 6% of vaccinated children born to HBsAg-positive mothers had a natural booster response [26,27]. In Thailand, natural booster responses were observed between 10 and 20 years after the start of primary vaccination of children born to HBsAg carrier mothers [28,29].
Investigation of memory B cell responses to hepatitis B surface antigen in health care workers considered as non-responders to vaccination
2010, VaccineCitation Excerpt :Memory B cells have the capacity to respond rapidly to previously encountered Ag by means of a clonal expansion and differentiation in plasma cells secreting high-affinity antibodies. Administering a booster dose of HBs-Ag vaccine results in a vigorous anamnestic response, thus demonstrating that immune memory against HBV infection lasts longer than anti-HBs antibodies [19]. Recent studies have also directly detected memory B cells despite undetectable levels of anti-HB antibodies [20].
Protective immunity after hepatitis B vaccination
2009, Arab Journal of Gastroenterology