Quantifying the population effects of vaccination and migration on hepatitis A seroepidemiology in Australia

Jayasundara, Duleepa; Hui, Ben B; Regan, David G.; Heywood, Anita E.; MacIntyre, C. Raina; Wood, James G.

doi:10.1016/j.vaccine.2017.08.022

Cited by 4 publications

(8 citation statements)

References 20 publications

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“…In addition to our finding of large declines in R 0 in the pre‐vaccine period, our model shows a further marked decline in R eff after the introduction of vaccination in 1994. Seroprevalence data in this period show large rises in population immunity and can be explained by high rates of opportunistic vaccination and migration from high‐endemicity settings. Similar transitions have been projected in other settings; for example, Bauch et al reported that universal vaccination at 1 year of age with phasing out of targeted vaccination would reduce reported incidence by 60% over 80 years (from 2006 to 2085) in Canada.…”

Section: Discussionmentioning

confidence: 52%

“…Studies of the duration of hepatitis A vaccine protection are naturally censored by <25 years of data availability but long‐term cohort studies supported by modelling projections report at least 14 years and 25 years of observed evidence, with immune response found to be similar to that induced by a natural infection, inferring lifelong protection by hepatitis A vaccination. Australia continues to see high rates of migration from intermediate‐ and high‐endemicity countries and available data on vaccine uptake suggest that this if anything has increased with time in the period up to 2015.…”

Section: Discussionmentioning

confidence: 99%

“…Age‐ and time‐dependent vaccination rates in Australia were obtained from our previous study reporting estimates of average vaccination rates during 3 consecutive 5‐year time periods (’94‐’98, ’99‐’03 and ’04‐’08) stratified by age.…”

Section: Methodsmentioning

confidence: 99%

“…In the general community, while there have been a number of larger point source, food‐borne outbreaks, there has been a clear transition to most infections being travel‐related. This has been driven by high opportunistic vaccination rates as well as a sustained inflow of seropositive immigrants to Australia from regions of high hepatitis A endemicity that contributes to maintaining the proportion of the population that is susceptible to infection at a low level, thereby suppressing the occurrence of epidemics in the general population.…”

Section: Introductionmentioning

confidence: 99%

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Modelling the decline and future of hepatitis A transmission in Australia

Jayasundara

Hui

Regan

et al. 2018

Journal of Viral Hepatitis

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Summary Hepatitis A incidence has declined in most countries through a combination of prevention measures, augmented through the use of a highly effective vaccine. In Australia, the proportion of the population susceptible to hepatitis A infection has declined over time due to high rates of opportunistic vaccination as well as the sustained inflow of seropositive immigrants from high‐endemicity countries. These factors have contributed to a rapid decline in incidence. An age‐structured hepatitis A transmission model incorporating demographic changes was fitted to seroprevalence and disease notification data and used to project incidence trends and transmission potential for hepatitis A in the general population. Robustness of findings was assessed through worst‐case scenarios regarding vaccine uptake, migration and the duration of immunity. The decline in age‐specific seroprevalence until the introduction of hepatitis A vaccine in 1994 was well explained through a declining basic reproduction number (R0) that remained >1. Accounting for existing immunity, we estimated that the effective reproduction number (Reff) <1 in the general population of Australia since the early 1990s, declining more rapidly after the introduction of the hepatitis A vaccine. Future projections under a variety of scenarios support Reff remaining <1 with continued low incidence in the general population. In conclusion, our results suggest that sustained endemic transmission in the general Australian population is no longer possible although risks of sporadic outbreaks remain. This suggests potential for local elimination of hepatitis A infection in Australia, provided that elimination criteria can be defined and satisfied in risk groups. The methodology used here to investigate elimination potential can easily be replicated in settings such as in the USA where sequential seroprevalence studies are supported by routine notification data.

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Section: Discussionmentioning

confidence: 52%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modelling the decline and future of hepatitis A transmission in Australia

Jayasundara

Hui

Regan

et al. 2018

Journal of Viral Hepatitis

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“…20 However other factors, such as increasing vaccination coverage in risk groups (including travellers and men who have sex with men) and seropositive migrants from hepatitis A endemic countries, are also likely to have contributed. 21 Reasons for the apparent increasing trend over recent years in hepatitis A hospitalisation rates for both Aboriginal and Torres Strait Islander and other people are unclear.…”

Section: Aboriginal and Torres Strait Islander Othermentioning

confidence: 99%

Vaccine Preventable Diseases and Vaccination Coverage in Aboriginal and Torres Strait Islander People, Australia, 2011–2015

2019

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