If U Had Hepatitis and It Was Cured Can You Get It Again

Lancet Infect Dis. Author manuscript; bachelor in PMC 2013 May 1.

Published in final edited form equally:

PMCID: PMC3608418

NIHMSID: NIHMS440537

Hepatitis C virus clearance, reinfection, and persistence, with insights from studies of injecting drug users: towards a vaccine

Jason Grebely, PhD, Prof Maria Prins, PhD, Prof Margaret Hellard, PhD, Andrea L Cox, PhD, William O Osburn, PhD, Georg Lauer, MD, Kimberly Page, PhD, Prof Andrew R Lloyd, PhD, and Prof Gregory J Dore, PhD, on behalf of the International Collaboration of Incident HIV and Hepatitis C in Injecting Cohorts (InC³)

Abstract

Hepatitis C virus (HCV) was discovered more than two decades agone, only progress towards a vaccine has been slow. HCV infection will spontaneously clear in well-nigh 25% of people. Studies of spontaneous HCV clearance in chimpanzees and man beings take identified host and viral factors that could be of import in the command of HCV infection and the blueprint of HCV vaccines. Although data from studies of chimpanzees advise that protection confronting reinfection is possible after spontaneous clearance, HCV is a homo disease. Results from studies of reinfection risk later on spontaneous clearance in injecting drug users are alien, but some people seem to take protection against HCV persistence. To guide future vaccine evolution, we appraise data from studies of HCV reinfection after spontaneous clearance, discuss flaws in the methods of previous human studies, and propose essential components for future investigations of control of HCV infection.

Introduction

Two decades have passed since the discovery of hepatitis C virus (HCV),¹ and although agreement of the virus has greatly increased and major advances in therapeutic evolution have been made, no constructive vaccine exists to prevent new infections. Spontaneous viral clearance occurs in near 25% of individuals, generally in the beginning 6 months of infection.^two Researchers are interested in whether spontaneous viral clearance (host immune-mediated clearance) confers protection against reinfection, specially against reinfection followed past viral persistence.

Studies of chimpanzees^3–8 and homo beings^9,10 have shown that, subsequently HCV reinfection, control of viral replication is ameliorate, elapsing of infection is shorter, and the likelihood of viral clearance is higher than in chief infection. These findings advise that previous clearance of an HCV infection could provide some protection against persistent reinfection. In chimpanzees, rapid virological control after reinfection is associated with HCV-specific T-prison cell responses.^v,7,8 Cohort studies of injecting drug users (IDUs)^10–19 have assessed whether previous spontaneous HCV clearance provides protection against HCV reinfection, with inconsistent results. Immunological correlates of improved clearance after reinfection might place potential targets for vaccine development.²⁰

Acute HCV infection and clearance

HCV virus is present in claret two–14 days afterwards initial exposure. Concentrations of alanine aminotransferase and aspartate aminotransferase increase and HCV-specific antibodies are produced xx–150 days after exposure.^21–23 Primary infection with HCV is mostly asymptomatic, although 15–30% of individuals develop symptomatic acute hepatitis illness within 5–12 weeks of exposure lasting 2–12 weeks.^24,25 Symptomatic principal HCV infection is often mild, with non-specific symptoms such as lethargy and myalgia, but individuals tin present with jaundice.^24,25 In near 25% of patients, acute infection is followed by viral clearance, defined every bit undetectable concentrations of HCV RNA in blood.² Most of these individuals clear infection by six months (73–86%) or 12 months (87–95%).^26–28 However, spontaneous HCV clearance after 1 year has been reported.^29,30 Most patients practice not have viral clearance and viraemia persists after vi months, leading to chronic infection and progression to cirrhosis in v–10% of individuals within xx years.³¹

Whether HCV infection spontaneously clears or persists is affected by a complex set of interactions between virus and host that is simply partly understood. Host factors such equally female sex,^two,18,32 initial allowed response,^33–37 virus-specific neutralising antibodies,^38,39 and host genetics^40–42 have been associated with clearance in prospective studies of acute HCV infection. Pathogen-associated factors, such as variety of HCV viral quasispecies^43,44 and HCV genotype,⁴⁵ might also be linked with clearance. In large cross-sectional studies of people infected with HCV for an unknown period, viral clearance is associated with several factors: female person sex,^2,46,47 immature age,^48,49 indigenous Canadian indigenous origin,⁴⁶ non-black ethnic origin,^l–52 absence of booze-use disorder,⁵³ no tobacco utilise,^fifty HIV-negative status,^{46–48,51,53} and chronic hepatitis B infection.^{47,48,50,52,54,55} However, these cross-sectional studies of individuals who tested positive on tests for HCV antibodies—ie, have been exposed to the virus at some point—are subject to selection bias, in view of the potential for HCV reinfection in people with initial spontaneous clearance during long-term follow-up.

Host polymorphisms of proteins such as HLA class I and 2, natural-killer-jail cell receptors, chemokines, interleukins, and of interferon-stimulated genes have been associated with control of HCV.^forty Notwithstanding, the genetic associations identified have non been confirmed in independent cohorts, differ in diverse populations, and studies are limited by small sample size or varying definitions of HCV outcome; moreover, little is known about their functional basis.^xl

Mayhap the strongest genetic association with HCV clearance is with IL28B.^41,42,56,57 This factor encodes interferon-λ 3, which is involved in viral control.⁵⁸ www.thelancet.com/infection Individuals with unfavourable IL28B genotypes are less probable to clear HCV infection than are those with favourable alleles.^41,42,56,57 This association is independent of both sex and symptomatic HCV infection with jaundice.⁴² Although the mechanism by which interferon- λ iii acts during HCV infection is unknown, this cytokine has straight antiviral actions in vivo and readily inhibits HCV replication in hepatoma cells.⁵⁸

A strong host allowed response (innate and adaptive) is important for spontaneous HCV clearance.^33–36 During acute infection, HCV persistence tin occur through evasion of the innate allowed response.³⁷ HCV could partly or completely counter the innate immune response by disrupting cellular signalling pathways that lead to interferon synthesis, and by subverting cellular signalling to restrict expression of interferon-stimulated genes and block their antiviral effcts.³⁷ The response of interferon-stimulated genes seems to be important since findings from chimpanzee studies suggest that their expression in the liver during acute HCV correlates with spontaneous clearance.⁵⁹

Available evidence indicates that individuals with primary infections that later clear have strong, broadly specific, and sustained adaptive cellular immune responses, whereas many of those who develop persistent infection take weak cellular immune responses that do not last.^38,39 Stiff cellular allowed responses have too been noted in high-risk individuals who do not accept HCV antibodies, suggesting that clearance tin can occur rapidly, before antibodies are produced.^{threescore,61}

Virus-specific neutralising antibodies tin bulldoze sequence development and might touch the outcome of infection⁶² and protection confronting reinfection.¹⁰ The all-time available assay systems for HCV neutralising antibodies use virus-like particles or envelope sequences incorporated inside pseudotyped viruses that maintain the native configuration of the HCV envelope glyco-proteins. Initial studies with this method showed that neutralising antibodies were rare in individuals who went on to resolve infection,^63–65 although this finding was non universally reported.⁶⁶ Nevertheless, a longitudinal report with homologous viral pseudoparticles showed that clearance of infection was associated with rapid development of neutralising antibodies.⁶⁷

HCV reinfection

Occurrence

Studies of HCV reinfection provide insight into factors important for protection against persistent infection, which is a central issue for vaccine design. Yet, written report of HCV reinfection in people has been difficult. Studies in chimpanzees have generated the near robust data on HCV reinfection considering experiments can be advisedly designed to study re-exposure and reinfection. Despite apparently efficient allowed responses in primary infection resulting in viral clearance, reinfection can occur in chimpanzees with both homologous and heterologous viruses.^68,69 Even so, reinfection episodes have been linked with improved command of viral replication, a short course of infection, and an increased likelihood of viral clearance compared with primary infection.^3–8 Rapid virological control later on chimpanzees are reinfected is connected to HCV-specific T-cell responses.^5,7,8 When CD4 T cells are depleted in vivo before reinfection, persistent HCV infection ensues.⁷⁰ Similarly, depletion of CD8 T cells extended HCV viraemia, which was controlled just when this subset of cells recovered in the liver.⁸ In this context, cross-genotype immunity has been recorded,⁶ but viral persistence seems more likely in the setting of heterologous reinfection.^vii

Nevertheless, HCV is a uniquely human disease, and investigations of HCV reinfection in people have improved understanding of protective amnesty. In an early example series,⁷¹ reinfection was recorded in 5 children with thalassaemia that were re-exposed to HCV after spontaneous clearance. Reinfection has also been reported in case studies of IDUs^{ix,12,thirteen,17,28,72–75} and men who accept sexual activity with men.⁷⁶ Several observational cohort studies of IDUs with continuing gamble behaviours for HCV acquisition have been done, assessing HCV reinfection later on spontaneous clearance (tables 1, 2).^{10,12–19,77} Collectively, these studies of IDUs are valuable because they give a human being model for protection against HCV infection. Specifically, these investigations enable measurement of the incidence of HCV reinfection (and how it compares with incidence of master HCV infection), the proportion who develop persistent HCV reinfection (and hence incidence of persistent infection), and the natural history of HCV reinfection.

Table 1

Characteristics of injecting drug users assessed for HCV infection and reinfection in longitudinal studies

	Country	Accomplice blueprint	HCV virological assessments	Written report menstruum	Written report populations	Age (years)	Men	Indigenous origin	Infected with HIV at baseline	Injection drug use at baseline	Frequent injecting^*
Mehta¹²	USA	Prospective	Retrospective	1988–95	Non infected (n=164) vs HCV clearance (northward=98)	32 (vii·0) vs 41 (half-dozen·iii)	121 (74%) vs 58 (59%)	African-American: 146 (90%) vs 87 (90%)	17 (ten%) vs 36 (37%)	129 (79%) vs 64 (65%)	35 (21%) vs 32 (33%)
Grebely¹³	Canada	Retrospective	Retrospective	1992–2005	Not infected (north=926) vs HCV clearance (north=152)	44 (3·three) vs 41 (11·3)	628 (67%) vs 93 (61%)	White: 541 (58%) vs 69 (45%)	68 (vii%) vs 35 (23%)	241 (26%) vs 73 (48%)	129 (14%) vs 38 (25%)
Micallef¹⁴	Commonwealth of australia	Retrospective	Retrospective	1993–2002	Not infected (due north=423) vs HCV clearance (n=xviii)	23 (15–54)^† vs 23 (16–32)^†	166 (39%) vs vii (39%)	NA	NA	NA	61% vs 56%^‡
Aitken¹⁵	Australia	Prospective	Prospective	2005–07	Not infected (n=55) vs HCV clearance (n=fifty)	25 vs 27	19 (35%) vs 22 (44%)	White: 37 (74%) vs 45 (82%)	0 (0%) vs 0 (0%)	55 (100%) vs 50 (100%)	29 (58%) vs twenty (36%)
van de Laar¹⁷	Netherlands	Prospective	Retrospective	1985–2005	Not infected (north=168)^§ vs HCV clearance (n=24)	29 vs 27	112 (67%) vs 9 (38%)	Western European: 139 (83%) vs	4 (2%) vs 2 (8%)	100 (60%) vs 23 (96%)	26 (16%) vs 12 (l%)
Page¹⁸	USA	Prospective	Prospective	2000–08	Not infected (n=380) vs HCV clearance (north=22)	23 vs 22	253 (67%) vs 10 (46%)	White: 290 (77%) vs xvi (73%)	half dozen (2%) vs 0 (0%)	380 (100%) vs 22 (100%)	122 (33%) vs four (24%)
Osburn^ten	USA	Prospective	Prospective	1997–2008	Non infected (northward=179) vs HCV clearance (n=22)	23 vs 25	eighty (45%) vs 10 (45%)	White: 134 (75%) vs 22 (100%)	NA vs 1 (4%)	NA vs 22 (100%)	NA
Dove⁷⁷	The states	Prospective	Prospective	NA	HCV clearance (n=vi)	46 (37–seventy)^†	4 (67%)	African-American: 2 (33%)	0 (0%)	6 (100%)	6 (100%)
Currie^sixteen	USA	Prospective	Prospective	1997–2001	HCV clearance (n=29)	47 (7·5)	16 (55%)	African-American: 7 (24%)	12 (41%)	17 (59%)	NA
Grebely¹⁹	Australia	Prospective	Prospective	2004–07	HCV clearance (n=30)	33	20 (67%)	White: 28 (93%)	7 (23%)	five (17%)	2 (7%)

Table 2

Infection and reinfection in injecting drug users in longitudinal studies

	Study populations	Number of new infections during follow-up	Median follow-up (years)	Incidence rate per 100 person- years	Crude incidence rate ratio	Adjusted ratio (95% CI)	p value	Median HCV RNA testing interval for patients previously infected (months)^*	Clearance of reinfection in patients whose infection had previously cleared^†	Reinfection in prevalent or incident cases?
Mehta¹²	Not infected (north=164) vs HCV clearance (north=98)	35 vs 12	two·4 vs 2·i	8·half-dozen vs 5·4	0·63	0·45 (0·23–0·88)^†	0·02	6·3 (6)	6 of 9 (67%)^‡	Prevalent
Grebely^thirteen	Not infected (northward=926) vs HCV clearance (n=152)	172 vs 14	ii·eight vs 5·ii	8·1 vs 1·viii	0·22	0·23 (0·x–0·51)§	<0·001	15·6	four of 14 (29%)	Prevalent
Micallef¹⁴	Not infected (n=423) vs HCV clearance (n=18)	114 vs 13	i·0 vs ane·2	17·0 vs 42·0	2·47	1·1^¶	0·eighty	5·0 (6)	3 of seven (43%)	Incident
Aitken¹⁵	Not infected (north=55) vs HCV clearance (n=fifty)	10 vs 23	NA	fifteen·v vs 46·8	3·02	2·54 (ane·11–5·78)^‡	0·027	3·viii (iii)	nine of 22 (41%)	Prevalent and incident
van de Laar¹⁷	Non infected (n=168)^\|\| vs HCV clearance (n=24)	58 vs nine	three·half dozen vs 10·5	6·7 vs ix·9	1·5	NA	NA	vii·3 (4–half dozen)	iii of nine (33%)	Incident
Folio¹⁸	Non infected (northward=380) vs HCV clearance (n=27)	132 vs vii	NA	26·7 vs 24·six	0·92	NA	NA	three·0 (3)	7 of vii (100%)	Incident
Osburn¹⁰	Not infected (due north=179)^** vs HCV clearance (n=22)	62 vs xi	NA	27·2 vs 30·1	1·eleven	NA	NA	1·0 vs one·0 (one)	10 of 12 (83%)	Incident
Currie¹⁶	HCV clearance (n=29)	0	5·5	0·0	NA	NA	NA	NA (6)	0 of 29	Prevalent
Grebely¹⁹	HCV clearance (n=30)	2	1·1	6·1	NA	NA	NA	3·0 (3)	2 of 2 (100%)	Incident

Similar rates of primary infection and reinfection afterward adjustment for potential differences in risk behaviour would advise that previous clearance of HCV infection does not provide sterilising immunity against reinfection. However, the proportion of persistent HCV reinfections should be measured. For example, if most reinfections spontaneously cleared, in that location would exist a strong argument for some level of protection. Measurement of the size and duration of HCV viraemia during reinfection equally compared with primary infection helps to constitute whether protection is genetic or immunological. A reduction in the degree or elapsing of viraemia would advise that caused protective immunity has a role, because fixed genetic factors would not adapt and go more efficient equally does the immune response. Studies of HCV reinfection in IDUs (tables 1, 2) farther understanding of all three parameters and take implications for HCV vaccines.

Researchers in Baltimore (Md, USA) investigated whether previous clearance reduces the risk of HCV reinfection in a accomplice study.¹² Afterward adjustment for risk behaviour, individuals with previous HCV clearance were half as likely to be infected during follow-up every bit were those who had not been infected previously (table 2).¹² Further data supporting these findings came from a prospective accomplice of IDUs in Vancouver (BC, Canada).¹³ Chiefly, the median fourth dimension between HCV RNA testing was long in both studies (tabular array 2).¹³

Data from other cohorts, nonetheless, suggest that previous spontaneous clearance of HCV infection might not reduce risk of new infection.^{10,fourteen,fifteen,17,18} A retrospective accomplice study of immature, high-risk IDUs from Sydney (NSW, Commonwealth of australia)¹⁴—with more frequent testing than in the other studies^12,xiii—showed no difference betwixt incidence of HCV infection in individuals with no previous infection and in those with previous HCV clearance (tabular array 2). A prospective cohort report in Melbourne (VIC, Commonwealth of australia),¹⁵ also showed high reinfection rates in IDUs who had previously cleared HCV infection (tabular array 2). Previously infected IDUs with HCV clearance were 2·5 times more likely to become infected than were those who had not been previously infected. Similar findings have been reported in the Us.^10,18 Frequent monitoring of HCV infection status in a study of young IDUs from Baltimore¹⁰ showed infection rates of individuals who had no previous infection and of those with previous clearance were similar (tabular array 2).

In the netherlands, van de Laar and colleagues¹⁷ noted that HCV reinfection was at least every bit common as initial infection in their cohort (table 2). Although testing intervals for HCV reinfection were long, they recorded a decline in the incidence of HCV reinfection from 20·4 per 100 person-years in 1985–1995, to iv·2 per 100 person-years in 1995–2005. Incidence of initial HCV infection barbarous from 27·5 per 100 person-years in the belatedly 1980s to roughly 2·0 per 100 person-years in 2005. Collectively, these cohort studies suggest that rates of infection and reinfection are similar when curt testing intervals are used. Thus, HCV infection in people does not confer sterilising immunity.

Clearance of reinfection

Although reinfection is common, it does not e'er lead to persistent infection. Spontaneous clearance of HCV reinfection has been ofttimes recorded (tabular array two); data propose that some individuals tin clear HCV later ane exposure more than efficiently than tin others. Overall, clearance of the reinfection strain is fairly common, with some individuals able to spontaneously clear HCV with unlike genotypes from that of the initial infection.^{10,fourteen,15,eighteen}

A high rate of clearance of HCV reinfection is not surprising, because, by definition, individuals at hazard have had clearance of principal infection, and host characteristics are associated with clearance. Furthermore, information technology does not betoken that previous HCV infection with clearance changes the grade of reinfection. Rates of clearance subsequently reinfection are probably underestimated in most studies, considering HCV RNA testing intervals longer than one month could cause many cases of clearance to exist missed, and will therefore be biased to detection of HCV reinfections with viral persistence.⁸⁰ Furthermore, longitudinal follow-up of HCV reinfection cases with long intervals between tests will mean clearance cases are misclassified as persistent cases. Every bit such, caution must be used in interpretation of results of studies with long intervals between tests or short follow-up time.

Natural history of reinfection

As recorded in chimpanzees, prove indicates that HCV RNA concentrations later reinfection in people are lower, generally more transient, and shorter in duration than during initial infection.¹⁰ In a longitudinal study of IDUs,¹⁰ median duration of HCV viraemia was 4 times longer during initial infection than during reinfection (232 days vs 77 days) and peak median log HCV RNA concentration was lower (3·1 log IU/mL vs 6·vii log IU/mL),¹⁰ suggesting people develop adaptive protective amnesty (effigy).

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HCV infection, clearance, and reinfection

HCV reinfection events after spontaneous clearance take lower HCV RNA concentrations and shorter infection durations than initial HCV infection. HCV=hepatitis C virus.

The emergence of a new dominant virus during chronic infection (without a period free of viraemia) does not elicit an increased number of new HCV-specific T-cell responses,¹⁰ potentially because of virus-induced immune tolerance or burnout.^81,82 By dissimilarity, dissimilar responses of HCV-specific T cells during reinfection accept been documented.^x Additionally, a response of neutralising anti bodies to heterologous HCV pseudo-particles was noted in 60% of reinfected IDUs. Although neutralising antibodies do not generally neutralise heterologous HCV pseudoparticles during the astute phase of infections that progress to chronicity,^62,64 their presence in reinfected individuals was contained of the sequence deviation between the stimulating virus and the test HCV pseudo particle sequence.¹⁰ These data advise that reinfection is associated with the generation of cantankerous-reactive neutralising antibodies.

However, Osburn and colleagues¹⁰ detected new HCV-specific T-jail cell responses and cross-reactive neutralising antibodies in reinfected individuals who did not clear reinfection. Therefore, although improved cellular and humoral immune responses play a part in control of reinfection, they are probably not sufficient for protection confronting HCV reinfection with persistence in all cases. Further longitudinal investigation of adaptive immunity during principal infection and reinfection is necessary for reliable identification of the characteristics of protective immunity associated with repeated clearance of HCV infection and hence for futurity vaccine research.

Study limitations

The substantial heterogeneity of studies of HCV reinfection in people has an of import issue on interpretation, particularly on cross-study comparison. Apart from differences in study design (eg, follow-up of cohorts with previous infection and clearance vs cohorts with incident infection and subsequent reinfection) and statistical analyses, clear variation in historic period, sexual practice, ethnic origin, injecting chance behaviours, and presence of viral co-infections between the cohorts exists (tabular array 1). Risk behaviours of individuals with no previous infection and of those who take cleared an infection might differ and alter over time; hence, an analysis without adjustment for fourth dimension-updated risk behaviour as a proxy for re-exposure to HCV might have misleading findings.⁷⁸ Risk behaviour information needs to be collected accurately and regularly.

Definitions of viral clearance and reinfection vary between studies, as do the testing intervals and HCV RNA assays (table 2). The type of assay used is important because HCV seroconversion reliably allows detection of most all initial infections, just HCV reinfection necessitates detection of HCV RNA. Mathematical modelling has shown that studies with long HCV RNA testing intervals underestimate the incidence of HCV reinfection and probability of spontaneous HCV clearance later reinfection.⁸³

Futurity studies

Investigations into spontaneous HCV clearance of infection and reinfection and into correlates of protection could provide crucial insights into HCV vaccine design. Agreement of host factors essential for control of HCV—especially afterward several exposure events—will provide of import data nearly the development of components necessary for future vaccines. Because present results in people are inconclusive, further investigation into possible protective immunity is needed.

The ideal study to improve understanding of main HCV infection and reinfection, with a specific focus on potential development of an HCV vaccine that would provide protection against viral persistence, would be designed in a specific way. Uninfected, loftier-risk individuals would be recruited and followed upwardly, with tests for initial HCV infection every 1–3 months. All patients would ideally undergo HCV RNA testing to improve early on detection; those infected for the commencement time would always take this test to characterise the course of master HCV infection. Investigators would collect detailed data almost HCV risk behaviour, including any longitudinal changes. Primary HCV infection cases with viral clearance would be followed upwardly longitudinally for detection of HCV reinfection, with the same testing intervals as for initial detection. Individuals reinfected would be followed up for a long period to establish viraemia condition and the incidence and course of further reinfection events. Blood samples would take to be taken during primary HCV infection and reinfection with standardised collection methods and stored for detailed immunological and virological studies. Finally, HCV reinfection would be confirmed through phylogenetic characterisation of initial and reinfection strains.

Without prospective studies accordingly designed to accost whether HCV clearance provides protection against reinfection, pooling of information from existing cohorts with sufficient information is one fashion to move frontwards. The International Collaboration of Incident HIV and Hepatitis C in Injecting Cohorts (InC³) was established to create a merged multicohort projection of pooled information from well characterised cohorts of IDUs with astute HCV, to enable new in-depth studies non possible from each individual study, and to join researchers across disciplines. InC³ has successfully pooled behavioural, clinical, and virological data from 539 participants with astute HCV infection from nine cohorts in Australia, Canada, Europe, and the Usa.⁸⁴

Conclusions

Data from chimpanzee and human studies of master HCV infection, viral clearance, and HCV reinfection betoken that previous HCV infection is unlikely to provide substantial levels of acquired sterilising immunity. Notwithstanding, characterisation of the course of principal HCV infection and reinfection suggests that some protection against persistent HCV reinfection is developed through previous HCV infection.

Therefore, a vaccine that enhances spontaneous clearance of principal HCV could be more feasible than would a vaccine that prevents initial HCV infection.²⁰ The primary goal of such a vaccine would be to prevent the development of chronic HCV infection after repeat exposures. The prevention of chronic HCV infection would be a suitable endpoint, considering chronic—non acute—HCV infection is associated with HCV-related morbidity and bloodshed.

Search strategy and selection criteria

We searched Medline with the terms "hepatitis C", "HCV", "reinfection", "re-infection", "drug users", "epidemiology", "diagnosis", "natural history", and "spontaneous clearance" to identify reports published in English before Sept 15, 2011. The reference lists of identified reports were manually searched for further relevant papers. Cardinal abstracts at international meetings were also included. We selected reports on the basis of relevance to pattern, implementation, and analysis of studies related to HCV reinfection in injecting drug users and then assessed them for quality of methods and relevance of results.

Acknowledgments

Maria Prins was a Senior Visiting Fellow at the Kirby Institute for Infection and Immunity in Guild, University of New South Wales, Sydney, NSW, Australia when she drafted parts of the manuscript. Nosotros thank Campbell Aitken (Burnet Institute, Australia), Jennifer Evans (University of California San Francisco, USA), Thijs van de Laar (Amsterdam Public Wellness Service, Netherlands), Bart Grady (Amsterdam Public Health Service, Netherlands), and Charlotte van den Berg (Amsterdam Public Wellness Service, Netherlands) for profitable with the preparation of data; and Tanya Applegate (Kirby Institute for Infection and Immunity in Gild, Commonwealth of australia) for her constructive comments during the training of this report. This report was funded past the Australian Authorities Department of Health and Ageing. The views expressed in this report do non necessarily stand for the position of the Australian Authorities. JG is supported by a National Wellness and Medical Research Council Career Evolution Fellowship. MP was supported by the Public Wellness Service of Amsterdam. MH was supported by a National Health and Medical Enquiry Council Senior Researcher Fellowship. ALC and WOO were supported by the United states National Institutes of Wellness (U19 AI040035 and R01 AI077757), the Damon Runyon Foundation, and the Dana Foundation. GL is supported by the United states of america National Institutes of Health (U19 AI066345 and U19 AI082630). KP was supported by US National Institutes of Health (5R01DA016017 and 1R01DA031056-01A1) and the UCSF Liver Center (UCSF P30 DK026743). ARL and GJD were supported past National Health and Medical Inquiry Council Practitioner Fellowships.

Footnotes

Conflicts of interest

We declare that we accept no conflicts of involvement.

Contributors

JG, MP, and GD developed the outline and concept for the Review, and finalised the first typhoon. All authors assisted in writing of the first draft according to their area of expertise and contributed to the final editing of the report.

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Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3608418/