Peer-reviewed article
Long-term immunity after HBV vaccine: shall we consider a change? A 20-year-follow-up study
Fonzo M, Amoruso I, Baldovin T, Trevisan A, Bertoncello C ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study followed 5,485 people for 20 years after receiving hepatitis B vaccine in infancy to understand how long protection lasts. Researchers found that children vaccinated later in their first year of life developed higher antibody levels that persisted longer into adulthood. For every month delay in giving the first dose during the first year, the risk of low antibody levels 20 years later decreased by 18 percent. The findings suggest that timing of vaccination within the first year may affect long-term immunity.
Key points
- Mean anti-HBs antibody titre increased from 46 IU/l (first trimester) to 193 IU/l (fourth trimester) of life at first vaccination
- Proportion with protective titre <10 IU/l decreased from 51% to 18% comparing earliest to latest vaccination in first year
- Each additional month delay in first dose reduced risk of low titre at 20 years by 18% (AOR: 0.84)
- Longer time intervals between 2nd and 3rd doses also associated with better antibody persistence (AOR: 0.89 per month)
- Low titre does not necessarily mean lack of protection; interpretation requires consideration of local HBV epidemiology
Limitations
The study does not directly measure clinical protection or infection rates, only antibody persistence. The findings are observational and do not establish causation, and generalisability may be limited by the specific population studied.
Abstract
Abstract Introduction Although vaccines against HBV have been available since the 1980s, the long-term immunity is still debated. When assessing immune persistence, a number of clearly defined variables must be taken into account. Often the expression ‘infant vaccination’ means the administration within the first year of life at any age, but a difference of a few months may imply a different antibody persistence over the years. This study assessed the anti-HBs titre 20 years after the primary vaccination course and estimated the effect of age at 1st dose and time interval between doses on long-term protection. Methods Data on age, sex and date of administration were collected. Inclusion criteria: born to negative mother, 3-dose schedule, no previous HBV infection, age at enrolment 18-24 years; age at 1st dose 2-12 months. Titres ≥10IU/l were considered protective. A logistic regression was performed, adjusting for sex, follow-up time and date of 1st dose and analysis. Results We included 5,485 participants (64% female). The mean anti-HBsAg increased from 46, 52, 85 to 193IU/l when the 1st dose was administered in the I, II, III or IV trimester of life, respectively. Similarly, the proportion of individuals with titre <10IU/l decreased from 51 to 18% between the two extreme quarters. The risk of a titre <10IU/l decreased with age at the 1st dose (AOR: 0.84; 95%CI: 0.78-0.91 per one-month increase) and time between the 2nd and 3rd doses (AOR: 0.89; 95%CI:0.85-0.94). Conclusions The mere presence of a titre <10IU/l does not equate lack of protection. However, antibody levels are very different depending on the actual age of vaccination. One-month delay within the first year is associated with a -18% chance of a titre <10IU/l 20 years later. Although this information needs to be combined with local epidemiology and surveillance to obtain an informed risk-benefit balance, the implications from a public health and economic perspective may be diverse and worth considering. Key messages • Still within the first year of life, a delay in the administration of the 1st dose of HBV vaccine and a longer time between the 2nd and 3rd dose imply a higher antibody persistence even 20 years later. • Considering the local circulation of HBV and surveillance, this result could be taken into account to obtain an informed risk-benefit balance.
Findings the Hub has extracted
Each claim below is labelled by its type of design and links back to this report.
- Intervention
- Hepatitis B vaccination with 3-dose schedule; comparison of outcomes by age at first dose and intervals between doses
- Population
- 5,485 individuals born to hepatitis B negative mothers, vaccinated with 3-dose schedule between 2-12 months of age, followed up at age 18-24 years
Key finding
Mean anti-HBs titre at 20 years was significantly higher when first dose delayed: 46 IU/l (first trimester) vs 193 IU/l (fourth trimester of life)
M et al. · PubMed Central (PMC) · 1 Oct 2022