UCL Grand Challenges


Immune Dynamics after Repeated Influenza Vaccination

Report on the outcomes of research into Immune Dynamics after Repeated Influenza Vaccination, supported by the UCL Grand Challenges and the University of Hong Kong.

UCL-HKU Immune Dynamics Flu - "Colorful Childhood" by Momentchensammler is licensed under CC BY 2.0

1 February 2019


Grant: Hong Kong University and Grand Challenges
Year awarded: 2017-18
Amount: £9,965.24 from UCL and HK$100,000 (~£10,000) from HKU


  • Professor Andrew Hayward, UCL Farr Institute of Health Informatics Research
  • Ms. Ellen Fragaszy, UCL Farr Institute of Health Informatics Research
  • Professor Benjamin Cowling, HKU School of Public Health
  • Dr. Nancy Hiu Lan Leung, HKU School of Public Health

Report on the outcome of the Hong Kong cohort arm of a joint HKU-UCL study of influenza dynamics, supported by the University of Hong Kong and UCL Grand Challenges

Prior to the 2009/10 influenza season, 796 children were enrolled in a cohort study. 367 were followed for five years and gave blood samples every six months. The project team explored the trajectories of HAI antibody titers.

Deliverable 1

Statistical analyses to study the effect of repeated influenza vaccination on antibody waning in both the HK and UK cohorts, specifically:

  1. To estimate the antibody waning after repeated vaccination over time;
  2. To estimate the correlation of HAI titer with protection against laboratory-confirmed infection; and
  3. To determine whether this protection differs between individuals who received multiple influenza vaccinations over the years

Preliminary Results

  • Leung NHL, Perera RAPM, Fang VJ et al. Waning of antibodies against influenza virus after vaccination or infection. 11th Annual CEIRS Network Meeting, 2018. New York, US. [Poster]
  • Leung NHL, Perera RAPM, Fang VJ et al. Waning of natural or vaccine-induced serum antibodies against human influenza virus over multiple years. São Paulo School of Advanced Sciences on Vaccines, 2018. São Paulo, Brazil. [Poster] [Scholarship awarded]
  • Both presentations are being written up for publication in journals
Figure 1. Influenza HAI antibody titer measured in same individuals every 6 months over five years since their last influenza vaccination or PCR-confirmed influenza A/B virus infection.
A) Individuals who have reported never receive an influenza vaccination, nor had a PCR-confirmed influenza A/B virus infection.
B) Individuals who had reported received at least once influenza vaccination but did not have a PCR-confirmed influenza A/B virus infection. pH1: Influenza A(H1N1pdm09); sH3: A(H3); B.Vic: Influenza B(Victoria); B.Yam: B(Yamagata).


Deliverable 2

To organise two virtual half-day workshops with a consortium of multi-disciplinary scientists, to:

  1. Identify a unifying research agenda and future funding opportunities
  2. Establish a writing group to develop applications for further grant funding

The team have now met three times (in New York, London and Stockholm) to discuss the project and future research directions.

Grant Applications

As a result of the meetings, the project team have contributed to two recent grant applications:

  1. Waning of vaccine- or infection-induced serum antibodies against influenza hemagglutinin and neuraminidase in children. NIAID Centers of Excellence for Influenza Research and Surveillance (CEIRS), United States. [Under consideration, HK$3.5m]

  2. Control of influenza: individual and population immunity. Theme-based Research Scheme 2019/20, Hong Kong. [Invited for full proposal, HK$75m]

Download Final HKU Report