Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

A rise in invasive Haemophilus influenzae type b (Hib) infections occurred 8 years after vaccine introduction in the United Kingdom. Aspects of Hib vaccine delivery unique to the United Kingdom have been implicated. The authors developed a fully age-structured deterministic susceptible-infected-resistant-susceptible mathematical model, expressed as a set of partial differential equations, to better understand the causes of declining vaccine effectiveness. We also investigated the consequences of the vaccine's impact on reducing Hib transmission for maintenance of immunity. Our findings emphasized the importance of maintaining high post-immunization antibody titres among age groups at greatest risk of invasive infections. In keeping with UK population-based estimates, low direct efficacy of immunological memory against disease was found, cautioning against over-reliance on evidence of priming alone as a correlate of population protection. The contribution of herd immunity to disease control was reinforced. Possible intervention strategies will be explored in subsequent work.

Original publication




Journal article


Epidemiol Infect

Publication Date





800 - 812


Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Antibodies, Bacterial, Biomarkers, Child, Child, Preschool, Disease Transmission, Infectious, Haemophilus Infections, Haemophilus Vaccines, Haemophilus influenzae type b, Host-Pathogen Interactions, Humans, Infant, Infant, Newborn, Middle Aged, Models, Theoretical, United Kingdom, Vaccines, Conjugate