News Article | April 20, 2017
ILC 2017: Eight studies being presented at The International Liver Congress™ 2017 demonstrate contrasting evidence on the potential link between direct-acting antiviral treatment for hepatitis C and liver cancer According to data from eight studies being presented at The International Liver Congress™ 2017 in Amsterdam, The Netherlands, there remains continued debate on whether patients are at risk of developing liver cancer after achieving sustained virologic response (SVR) with a direct-acting antiviral (DAA) regimen for Hepatitis C virus (HCV). Investigators will present the results of their studies that show both sides of the argument - DAA therapy is associated with a higher risk of liver cancer compared with interferon-based therapy, versus there is no difference in liver cancer risk following cure with either therapy. Whilst remarkable progress has been made in the development of successful antiviral therapies for HCV infection, some recent studies suggest that curing patients does not eliminate the risk of developing liver cancer. There also appears to be an unexpectedly high rate of liver cancer (also known as hepatocellular carcinoma [HCC]) recurrence in patients who previously had their tumour treated successfully and had received DAAs.1 This claim was further supported by a Spanish study led by Dr Maria Reig and Dr Mariño, Hospital Clinic Barcelona, Spain in which patients with HCV and HCC who had previously been cured of HCC received DAA therapy. After a median 12.4 month follow-up, following treatment with DAAs, the rate of HCC coming back (recurrence) was 31.2% (24/77) and of those who received HCC treatment at recurrence, 30% (6/20) of patients presented progression in the immediate 6-month follow-up. This is an update of the study that will be published in the May 2017 issue of Seminars in Liver Disease, and is available here: https:/ . "Our study offers further support to previous findings that there is an unexpected high recurrence rate of hepatocellular carcinoma associated with DAAs, and that this association may result in a more aggressive pattern of recurrence and faster tumour progression," said Dr Maria Reig, Barcelona Clinic Liver Cancer Group, Hospital Clinic Barcelona, Spain, and lead author of the study. "These data indicate that there needs to be further research conducted in this area, clarifying the mechanism for the association between liver cancer recurrence and DAA therapy." Identifying those patients at risk of liver cancer is essential, a task that Dr Etienne Audureau, Public Health, Henri Mondor University Hospital, Créteil, France, and colleagues attempted to achieve by developing a prognostic tool for HCC. They found that in patients with severe scarring of the liver due to HCV (compensated cirrhosis), failure to achieve SVR was the most influential factor in predicting liver cancer. In addition, risk factors for liver cancer differ according to SVR status. The investigators recommend that in patients with compensated cirrhosis, eradication of HCV should be achieved before liver function is impaired and people who have achieved SVR should be monitored for liver cancer after 50 years of age. The mechanisms behind the development of liver cancer following HCV cure are not yet understood. One group of investigators led by Prof Thomas Baumert, Inserm Institute for Viral and Liver Diseases, University of Strasbourg, France, aimed to investigate if HCV infections produce epigenetic and transcriptional changes that persist after the infection is cured, and whether these epigenetic changes drive liver disease and HCC following cure. They found that the epigenetic and transcriptional changes are only partially reversed by DAAs and persist after HCV cure, suggesting that these changes are a driver for liver cancer that develops after HCV infection has been cured. The investigators concluded that these findings open a new perspective to develop novel biomarkers to identify patients at high risk of HCC and provide an opportunity to develop urgently needed strategies for HCC prevention. On the other side of the debate, a systematic review, meta-analyses, and meta-regression study, by Prof Gregory Dore and Dr Reem Waziry from The Kirby Institute, UNSW Sydney, and colleagues, found no evidence for higher risk of HCC occurrence or recurrence following DAA treatment, compared with interferon-based HCV therapy. A total of 41 studies, including 26 on HCC occurrence and 15 on HCC recurrence (in total, n=13,875 patients) were included. In studies assessing HCC occurrence, average follow up was shorter and average age was higher in DAA studies compared to interferon studies; incidence was lower with longer follow-up and younger age. In studies assessing HCC recurrence, average follow up was also shorter. Ultimately, in the meta-regression analysis, no evidence in favour of a differential HCC occurrence or recurrence was found between DAA and interferon regimens, after adjusting for study follow-up and age. "Recent studies have reported contradicting evidence on risk of hepatocellular carcinoma following direct-acting antiviral therapy; our aim was to bring some clarity to this," said Prof Gregory Dore, Kirby Institute and lead author of the study. "These data show the higher incidence of HCC observed following DAA therapy can be explained by the shorter duration of follow-up and older age of participants, rather than the DAA treatment regimen." A Scottish study, led by Dr Hamish Innes, School of Health and Life Sciences, Glasgow Caledonian University, Scotland, found that the risk of liver cancer following SVR was not associated with the use of DAAs, but baseline risk factors. Furthermore, risk of HCC development was similar in patients taking interferon-free regimens versus interferon-containing regimens, following a multivariate adjustment (IRR: 0.96, p=0.929) and no significant differences in HCC risk were found when treatment regimen was defined in terms of DAA containing regimens versus DAA free regimens. These data indicate that rather than the treatment regimens themselves, it is the baseline risk factors that determine risk of hepatocellular carcinoma. Another interesting study in Japanese patients with HCV genotype 1 infection, found a reduced incidence of liver cancer following achievement of SVR after 12 weeks of therapy with an interferon-free regimen (ledipasvir plus sofosbuvir) to a similar degree as that obtained with an interferon-containing regimen (simeprevir with peginterferon plus ribavirin). This study, which was conducted by Dr Masaaki Korenaga, Kohnodai Hospital, National Center for Global Health and Medicine, Chiba, Japan, and colleagues, also found that unexpected development of liver cancer following SVR in patients without previous liver cancer could potentially be predicted by imaging procedures (computer tomography or enhanced magnetic resonance imaging). Similarly, a Chinese study led by Dr George Lau, from the Beijing 302-Hong Kong Humanity and Health Hepatitis C Diagnosis and Treatment Centre, in Beijing, China, found no increase in the incidence of liver cancer in patients who achieved SVR12 with DAA compared to peginterferon plus ribavirin. A Sicilian study conducted by Dr Vincenza Calvaruso, University of Palermo, Palermo, Italy, and colleagues, demonstrated that patients who achieved SVR with DAAs had a similar risk of developing liver cancer when compared to historical controls of patients with compensated cirrhosis who achieved SVR after interferon-based therapy. In addition, those who achieved SVR with DAAs had a lower risk of developing liver cancer than those patients whose HCV infection was not cured. "The original observations made by researchers from the Barcelona Clinic Liver Cancer Group have sparked a huge number of studies aimed at verifying the potential association between DAA treatment and increased HCC recurrence after cure," said Prof Francesco Negro, Divisions of Gastroenterology and Hepatology of Clinical Pathology, University Hospital of Geneva, and EASL Governing Board Member. "At this stage, there is no reason to alter treatment guidelines until the issue is definitively clarified. We cannot exclude, however, that we may have to revise post-SVR surveillance in some specific patient subgroups." This annual congress is the biggest event in the EASL calendar, attracting scientific and medical experts from around the world to learn about the latest in liver research. Attending specialists present, share, debate and conclude on the latest science and research in hepatology, working to enhance the treatment and management of liver disease in clinical practice. This year, the congress is expected to attract approximately 10,000 delegates from all corners of the globe. The International Liver Congress™ 2017 will take place from April 19 - 23, at the RAI Amsterdam, Amsterdam, The Netherlands. About The European Association for the Study of the Liver (EASL) Since its foundation in 1966, this not-for-profit organisation has grown to over 4,000 members from all over the world, including many of the leading hepatologists in Europe and beyond. EASL is the leading liver association in Europe, having evolved into a major European Association with international influence, with an impressive track record in promoting research in liver disease, supporting wider education and promoting changes in European liver policy. Contact For more information, please contact the ILC Press Office at: Session title: Parallel session: Liver tumours: from patient stratification to management Time, date, and location of session: 16:00 - 18:00, Thursday 20 April, Elicium 2 Abstract: No evidence for higher risk of hepatocellular carcinoma occurrence or recurrence following direct-acting antiviral HCV therapy: A systematic review, meta-analyses, and meta-regression (PS160), 16:00 - 16:15 Gregory Dore, Australia Session title: Parallel session: HCV: post SVR management and complications Time, date, and location of session: 16:00 - 18:00, Thursday 20 April, Hall 5 Abstracts presented in order of appearance in press release: Tumour recurrence after Interferon-free treatment for hepatitis C in patients with previously treated hepatocellular carcinoma discloses a more aggressive pattern and faster tumour growth (PS031), 16:00 - 16:15 Maria Reig, Spain Identifying residual risk of hepatocellular carcinoma following hepatitis C virus eradication in compensated cirrhosis: decision-tree and random forest models developed in the French multicenter prospective ANRS CO12 CirVir cohort (PS034), 16:45 - 17:00 Etienne Audureau, France Hepatitis C virus-induced epigenetic and transcriptional changes persist post cure (PS033), 16:30 - 16:45 Thomas Baumert, France Among cirrhotic patients with a hepatitis C sustained viral response, the risk of de-novo hepatocellular carcinoma relates to baseline factors and not the use of direct acting antivirals: results from a nationwide cohort (PS035), 17:00 - 17:15 Hamish Innes, United Kingdom Sustained virologic response by ledipasvir/sofosbuvir reduces the incidence of hepatocellular carcinoma in Japanese patients with HCV genotype 1 infection. - Comparison with Simeprevir with peginterferon plus ribavirin (PS036), 17:15 - 17:30 Masaaki Korenaga, Japan No increase in the occurrence rate of hepatocellular carcinoma in Chinese treated by direct-acting antivirals compared to Interferon after eradication of hepatitis c virus: A long-term follow-up (PS037), 17:30 - 17:45 George Lau, China Occurrence of hepatocellular carcinoma in patients with hepatitis C virus related liver disease treated with direct-acting antivirals (PS038), 17:45 - 18:00 Vincenza Calvaruso, Italy Gregory Dore: Advisory board member and receives honorarium from Gilead, Merck, Abbvie, Bristol-Myers Squibb, Janssen, has received research grant funding from Gilead, Merck, Abbvie, Bristol-Myers Squibb, Janssen, and travel sponsorship from Gilead, Merck, Abbvie, and Bristol-Myers Squibb Vincenza Calvaruso: Advisory Board for AbbVie, BMS, Gilead Sciences and Intercept. Grant and research support for MSD 1 Reig M et al. Unexpected early tumor recurrence in patients with HCV-related HCC undergoing interferon-free therapy; a note of caution. J Hepatol. 2016;65:719-726.
Ryom L.,Copenhagen University |
Mocroft A.,University College London |
Kirk O.,Copenhagen University |
Ross M.,Mount Sinai School of Medicine |
And 8 more authors.
AIDS | Year: 2014
Objectives: Whilst several antiretroviral drugs have been associated with moderate chronic kidney disease (CKD), their contribution to advanced CKD and end-stage renal disease (ESRD) remain unknown. Design: D:A:D participants with at least three estimated glomerular filtration rates (eGFR) after February 2004 were followed until the first of advanced CKD (confirmed eGFR≤30 ml/min,≥3 months apart), ESRD (dialysis ≥3 months/transplantation), 6 months after last visit or February 2012. Methods: Poisson regression was used to assess risk factors for advanced CKD/ESRD including exposure to potential nephrotoxic antiretroviral drugs and antiretroviral drug discontinuation rates according to latest eGFR. Results: Among 35 192 persons contributing 200 119 person years of follow-up (PYFU), 135 (0.4%) developed advanced CKD (n=114)/ESRD (n=21); incidence rate=0.67 [95% confidence interval (CI), 0.56-0.79]/1000 PYFU. Tenofovir (TDF) was particularly frequently discontinued as eGFR declined. After adjustment, those previously exposed but currently off TDF had similar advanced CKD/ESRD rate ratios compared with those unexposed [1.00 (95% CI, 0.66-1.51)], while those currently on TDF had reduced rates [0.23 (95% CI, 0.13-0.41)]. No consistent associations with other antiretroviral drugs were seen. Results were robust after time-lagging antiretroviral drug exposure, stratifying by baseline eGFR, and allowing for competing risks. Other predictors were diabetes, hypertension, baseline eGFR, smoking and current CD4 + cell count. The incidence rate in nonsmokers with baseline eGFR60 and no diabetes or hypertension was 0.16 (95% CI 0.09-0.26)/1000 PYFU. Conclusion: Neither current nor recent antiretroviral drug use predicted advanced CKD/ESRD during 6 years median follow-up in a large, heterogenenous and primarily white cohort. TDF discontinuation rates increased with decreasing eGFR, leaving a selected group still on TDF at lower advanced CKD/ESRD risk. Traditional renal risk factors and current CD4+ cell count were the strongest advanced CKD/ESRD predictors. © 2014 Wolters Kluwer Health.
PubMed | Harvard University, Kirby institute, Roskilde University, Instituto Nacional Of Ciencias Medicas Y Nutricion and 19 more.
Type: Journal Article | Journal: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America | Year: 2016
Previous studies suggest that nonnucleoside reverse-transcriptase inhibitors (NNRTIs) cause faster virologic suppression, while ritonavir-boosted protease inhibitors (PI/r) recover more CD4 cells. However, individual trials have not been powered to compare clinical outcomes.We searched databases to identify randomized trials that compared NNRTI- vs PI/r-based initial therapy. A metaanalysis calculated risk ratios (RRs) or mean differences (MDs), as appropriate. Primary outcome was death or progression to AIDS. Secondary outcomes were death, progression to AIDS, and treatment discontinuation. We calculated RR of virologic suppression and MD for an increase in CD4 cells at week 48.We included 29 trials with 9047 participants. Death or progression to AIDS occurred in 226 participants in the NNRTI arm and in 221 in the PI/r arm (RR, 1.03; 95% confidence interval, .87-1.22; 12 trials; n = 3825), death in 205 participants in the NNRTI arm vs 198 in the PI/r arm (1.04; 0.86-1.25; 22 trials; n = 8311), and progression to AIDS in 140 participants in the NNRTI arm vs 144 in the PI/r arm (1.00; 0.80-1.25; 13 trials; n = 4740). Overall treatment discontinuation (1.12; 0.93-1.35; 24 trials; n = 8249) and from toxicity (1.21; 0.87-1.68; 21 trials; n = 6195) were comparable, but discontinuation due to virologic failure was more common with NNRTI (1.58; 0.91-2.74; 17 trials; n = 5371). At week 48, there was no difference between NNRTI and PI/r in virologic suppression (RR, 1.03; 0.98-1.09) or CD4(+) recovery (MD, -4.7 cells; -14.2 to 4.8).We found no difference in clinical and viro-immunologic outcomes between NNRTI- and PI/r-based therapy.
PubMed | Melbourne Sexual Health Center, Sexual Health and Blood Borne Virus Unit, Health Diagnostic Laboratory, Darwin Lab and 8 more.
Type: Journal Article | Journal: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America | Year: 2016
Antimicrobial resistance (AMR) by Neisseria gonorrhoeae is considered a serious global threat.In this nationwide study, we used MassARRAY iPLEX genotyping technology to examine the epidemiology of N. gonorrhoeae and associated AMR in the Australian population. All available N. gonorrhoeae isolates (n = 2452) received from Australian reference laboratories from January to June 2012 were included in the study. Genotypic data were combined with phenotypic AMR information to define strain types.A total of 270 distinct strain types were observed. The 40 most common strain types accounted for over 80% of isolates, and the 10 most common strain types accounted for almost half of all isolates. The high male to female ratios (>94% male) suggested that at least 22 of the top 40 strain types were primarily circulating within networks of men who have sex with men (MSM). Particular strain types were also concentrated among females: two strain types accounted for 37.5% of all isolates from females. Isolates harbouring the mosaic penicillin binding protein 2 (PBP2)-considered a key mechanism for cephalosporin resistance-comprised 8.9% of all N. gonorrhoeae isolates and were primarily observed in males (95%).This large scale epidemiological investigation demonstrated that N. gonorrhoeae infections are dominated by relatively few strain types. The commonest strain types were concentrated in MSM in urban areas and Indigenous heterosexuals in remote areas, and we were able to confirm a resurgent epidemic in heterosexual networks in urban areas. The prevalence of mosaic PBP2 harboring N. gonorrhoeae strains highlight the ability for new N. gonorrhoeae strains to spread and become established across populations.
Bradshaw D.,Kirby Institute |
Matthews G.,Kirby Institute |
Danta M.,University of New South Wales
Current Opinion in Infectious Diseases | Year: 2013
Purpose of Review: Increasing evidence has emerged for permucosal transmission of hepatitis C amongst HIV-infected MSM. Recent Findings: A rising incidence of acute hepatitis C virus (HCV) in HIV-infected MSM has been observed since 2000 in Europe, Australia, USA and Asia. Transmission appears to occur through the permucosal rather than the more usual parenteral route. Although often multifactorial, permucosal risk factors can be classified as behavioural (sexual practices and mucosally administered drugs) and biological (HIV and sexually transmitted infections). This review will describe the epidemiology of HCV infection in this cohort. Current and future treatment strategies will also be outlined in the context of novel, orally bioavailable, directly acting antiviral therapies. Summary: An improved understanding of HCV epidemiology will allow implementation of more effective public health interventions to limit onward transmission of HCV. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Small W.,British Columbia Center for Excellence in |
Small W.,Simon Fraser University |
Small W.,Kirby Institute |
Maher L.,Kirby Institute |
And 7 more authors.
International Journal of Drug Policy | Year: 2013
Background: Illicit drug markets are a key component of the risk environment surrounding injection drug use. However, relatively few studies have explored how injection drug users' (IDUs) involvement in drug dealing shapes their experiences of drug market-related harm. This exploratory qualitative study aims to understand IDUs' dealing activities and roles, as well as the perceived benefits and risks related to participation in illicit drug markets, including experiences of drug market violence. Methods: Ten IDUs with extensive involvement in drug dealing activities were recruited from the Vancouver Injection Drug User Study (VIDUS) and participated in semi-structured qualitative interviews, which elicited discussion of experiences dealing drugs, perceived benefits and hazards related to dealing, and understandings of drug market violence. Results: Participant's involvement in drug market activities included corporate sales, freelance or independent sales, and opportunistic sales termed "middling" as well as drug market-related hustles entailing selling bogus drugs and robbing dealers. Participants primarily dealt drugs to support their own illicit drug use, and we found that arrest and criminal justice involvement, hazards stemming from drug debts, and drug market-related violence were key risks related to dealing activities. Conclusion: The challenges of managing personal consumption while selling drugs exacerbates the hazards associated with drug dealing. Efforts to address drug dealing among IDUs should consider both drug dependency and the material conditions that propel drug users towards dealing activities. Interventions should explore the potential of combining enhanced drug treatment programs with low threshold employment and alternative income generation opportunities. © 2013 .
Zablotska I.B.,Kirby Institute |
Prestage G.,Kirby Institute |
Wit J.D.,University of New South Wales |
Grulich A.E.,Kirby Institute |
And 2 more authors.
Journal of Acquired Immune Deficiency Syndromes | Year: 2013
Background: We aimed to describe the current use of antiretrovirals (ARVs) before unprotected anal intercourse (UAI) among Australian gay men, which may represent informal HIV preexposure prophylaxis (PrEP). Methods: Using data from Australian Gay Community Periodic Surveys conducted in 2011, we assessed the preventive use of ARVs before UAI and its association with sociodemographic characteristics, sexual practices, and drug use in the preceding 6 months. Associations were assessed using multivariate logistic regression analysis. Results: Of 3677 sexually active non-HIV-positive men, 2.5% reported taking ARVs before UAI. The likelihood of ARV use before UAI was significantly higher if any of the following behaviors were also reported: > 1 sex partner; UAI with casual partners, irrespective of reporting UAI with regular partners [adjusted odds ratio (AOR) = 2.36; 95% confidence interval (CI): 1.24 to 4.48] or not (AOR = 2.71; 95% CI: 1.44 to 5.07); injecting drugs at least monthly (AOR = 2.56; 95% CI: 1.03 to 6.36); using "party" drugs, occasionally (AOR = 2.23; 95% CI: 1.33 to 3.73) or regularly (AOR = 5.34; 95% CI: 2.99 to 9.56); and group sex while using party drugs, occasionally (AOR = 2.42; 95% CI: 1.29 to 4.53) or regularly (AOR = 5.31; 95% CI: 2.62 to 10.76). Among non-HIVpositive men in regular relationships with HIV-positive partners or partners of unknown HIV status, 1.7% and 4.7%, respectively, reported preventive ARV use before UAI. Conclusions: Our findings illustrate sporadic use of ARVs before UAI among gay men in Australia, which was associated with high-risk casual sex and party drug use. These initial data contribute to a much needed understanding of the informal use of ARVs for HIV prevention. Copyright © 2012 by Lippincott Williams and Wilkins.
Martin L.,Sydney Sexual Health Center |
Knight V.,Sydney Sexual Health Center |
Read P.J.,Sydney Sexual Health Center |
Read P.J.,Kirby Institute |
And 2 more authors.
Sexually Transmitted Diseases | Year: 2013
BACKGROUND: Sydney Sexual Health Centre (SSHC) Xpress clinic has significantly reduced the length of stay and waiting time for clients at SSHC but is currently only available to clients who can read and understand a high level of English. This reduces access for culturally and linguistically diverse (CALD) clients. This study sought to determine the acceptability of 4 proposed components of an express clinic model among CALD clients: computer-assisted self-interview (CASI), self-collection of swabs/urine specimens, not having a physical examination, and consultation with a health promotion officer rather than with a clinician. Differences in acceptability based on language group, new or return client status, sex worker status, clinic visited status, and age were analyzed. METHODS: A cross-sectional, anonymous questionnaire was offered to all female Chinese, Thai, and Korean clients attending SSHC between March and November 2012. Multivariate regression and Pearson χ statistical analyses were conducted using STATA 12 software. RESULTS: A total of 366 questionnaires were returned from 149 Thai, 145 Chinese, and 72 Korean participants. After multivariate analysis, the only predictor of willingness to use an express model of service provision was language group: overall, 67% Thai (odds ratio, 3.74: confidence interval [CI], 2.03-6.89; P < 0.01) and 64% Korean (odds ratio, 3.58; CI, 1.77-7.25, P < 0.01) said that they would use it compared with 35% Chinese. Age, history of sex work, new or returning clients, and general or language clinic attendance did not impact on choices. Within the preference for individual components of the model, more Thai women were happy with using a health promotion officer (43.2%) than Chinese (14.1%) or Korean (8.5%) (P < 0.001); no groups were happy with forfeiting a physical examination; Thai (48.6%) and Korean (40.9%) were happier with self-swabbing than Chinese women (23.9%, P < 0.001); and more Thai were happy to use a CASI (44.2%) than Chinese (12%) or Korean (11.1%; P < 0.001). CONCLUSIONS: This research shows that the components of an express model used at SSHC are not favorable to our CALD client base. Despite a CALD express clinic having the potential to reduce waiting times, most clients did not favor reduced waiting time over being physically examined or using a CASI. Copyright © 2013 American Sexually Transmitted Diseases Association. All rights reserved.
Naidoo S.,Jan Medical |
Wand H.,Kirby Institute
Sexually Transmitted Infections | Year: 2013
Background and objectives Trichomonas vaginalis is known to be the most common, curable, sexually transmitted infection among sexually active women and may be associated with the acquisition and transmission of HIV. The purpose of this analysis is to determine the prevalence and incidence of T vaginalis and assess risk factors associated with T vaginalis infection in a cohort of women participating in a clinical trial. Methods We analysed data from women participating in a phase III vaginal diaphragm trial conducted in two communities in Durban, South Africa from 2003 to 2006. A total of 3492 women were screened and 1485 women meeting the respective study eligibility criteria were enrolled. T vaginalis infection was determined at the initial screening visit and at quarterly visits among the enrolled women. Sexual behaviour and sociodemographic data were collected as per the study protocol. Combined data were analysed using STATA V.10.0. Results At baseline, prevalence of infection was 6.5%. The overall incident rate was estimated to be 8.6/100 women-years. Prevalent T vaginalis infection was associated with having a concurrent chlamydial infection and incident infections were associated with increased number of sex partners. Conclusions T vaginalis infection was found to be relatively high among this cohort of women. Given the association of this infection with HIV, there is an evident need for T vaginalis screening and treatment in populations at risk for both infections.
Schaffer A.,Center for Epidemiology and Research |
Muscatello D.,Center for Epidemiology and Research |
Cretikos M.,Center for Epidemiology and Research |
Gilmour R.,Center for Health Protection |
And 2 more authors.
BMC Public Health | Year: 2012
Background: In Australia, the 2009 epidemic of influenza A(H1N1)pdm09 resulted in increased admissions to intensive care. The annual contribution of influenza to use of intensive care is difficult to estimate, as many people with influenza present without a classic influenza syndrome and laboratory testing may not be performed. We used a population-based approach to estimate and compare the impact of recent epidemics of seasonal and pandemic influenza. Methods. For 2007 to 2010, time series describing health outcomes in various population groups were prepared from a database of all intensive care unit (ICU) admissions in the state of New South Wales, Australia. The Serfling approach, a time series method, was used to estimate seasonal patterns in health outcomes in the absence of influenza epidemics. The contribution of influenza was estimated by subtracting expected seasonal use from observed use during each epidemic period. Results: The estimated excess rate of influenza-associated respiratory ICU admissions per 100,000 inhabitants was more than three times higher in 2007 (2.6/100,000, 95% CI 2.0 to 3.1) than the pandemic year, 2009 (0.76/100,000, 95% CI 0.04 to 1.48). In 2009, the highest excess respiratory ICU admission rate was in 17 to 64 year olds (2.9/100,000, 95% CI 2.2 to 3.6), while in 2007, the highest excess rate was in those aged 65 years or older (9.5/100,000, 95% CI 6.2 to 12.8). In 2009, the excess rate was 17/100,000 (95% CI 14 to 20) in Aboriginal people and 14/100,000 (95% CI 13 to 16) in pregnant women. Conclusion: While influenza was diagnosed more frequently and peak use of intensive care was higher during the epidemic of pandemic influenza in 2009, overall excess admissions to intensive care for respiratory illness was much greater during the influenza season in 2007. Thus, the impact of seasonal influenza on intensive care use may have previously been under-recognised. In 2009, high ICU use among young to middle aged adults was offset by relatively low use among older adults, and Aboriginal people and pregnant women were substantially over-represented in ICUs. Greater emphasis on prevention of serious illness in Aboriginal people and pregnant women should be a priority in pandemic planning. © 2012 Schaffer et al.; licensee BioMed Central Ltd.