CROI 2019 Abstract eBook

Abstract eBook

Poster Abstracts

Methods: Using HIV-1 pol sequences reported to the U.S. National HIV Surveillance System for 6 states with ≥50% sequence data completeness for diagnoses during 2010–2017, we used HIV-TRACE to identify priority clusters among cases diagnosed in 2010–2012 (i.e., pairwise distance ≤0.005 substitutions/site; ≥3 cases diagnosed in 2012). We then identified cases diagnosed through 2017 that were genetically linked to these clusters, representing cluster growth in the 5 years after prioritization. We performed Bayesian molecular clock phylogenetic inference in BEAST on each cluster to estimate the number of 2013–2017 diagnoses that were incident infections (i.e., internal nodes after 2012) and prevalent, undiagnosed infections (i.e., internal nodes in or before 2012). For cases diagnosed in or before 2012, we determined viremia (i.e., viral load ≥200 copies/ml at last lab in or before 2012). These counts were treated as predictors in a cluster-level multivariate logistic regression analysis with incident infection as the outcome. Results: Of 116 priority clusters (initial size: 3–33 persons), 76 gave rise to ≥1 incident infection after 2012 based on phylogenetic inference. Among priority clusters, both undiagnosed infections and diagnosed, viremic cases were independently and equally associated with incident cluster growth in the following 5 years: odds of cluster growth increased by 57% for each additional viremic person (adjusted odds ratio=1.57, p=0.010) and 51% for each person with undiagnosed infection (adjusted odds ratio=1.51, p=0.019). Conclusion: These findings suggest that new infections in priority clusters originate equally from diagnosed, viremic cases and undiagnosed infections. These results highlight the importance of promoting retention in care and viral suppression as well as partner notification and other case-finding activities when investigating and intervening on priority molecular transmission clusters. 857 MOLECULAR SURVEILLANCE AS A MEANS TO EXPAND AN OUTBREAK INVESTIGATION: MA, 2015-2018 Betsey John 1 , Nivedha Panneer 2 , Matthew Tumpney 1 , Paul McClung 2 , Erica Dawson 2 , Kate Buchacz 2 , Kathleen Roosevelt 1 , Philip J. Peters 2 , Tracy Stiles 1 , Ellsworth M. Campbell 2 , WilliamM. Switzer 2 , Alfred DeMaria 1 , Kevin Cranston 1 , Sheryl Lyss 2 , for the Massachusetts Epi-Aid Investigation Team 1 Massachusetts Department of Public Health, Boston, MA, USA, 2 CDC, Atlanta, GA, USA Background: In mid-2016, the Massachusetts Department of Public Health (MDPH) identified increased HIV diagnoses among persons who inject drugs (PWID) in northeastern Massachusetts (NE MA). With CDC assistance, MDPH began an investigation in 2018 to characterize the outbreak and institute further control measures. We describe the contribution of molecular HIV surveillance to case finding and compare characteristics of cases initially determined to be linked through molecular surveillance with those already linked through traditional surveillance and partner services data. Methods: HIV diagnoses occurring during 01/2015 — 05/2018 were considered epidemiologically linked to the investigation 1) through residence, homelessness, HIV diagnosis, or HIV care in the cities of Lawrence or Lowell or 2) as a named partner of an investigation case. In 11/2017, MDPH rapidly implemented molecular surveillance; HIV pol sequences for persons in MA with a drug resistance test conducted during 01/2016—05/2018 were reported to MDPH and analyzed with Secure HIV-TRACE to identify molecular clusters using a pairwise genetic distance threshold of ≤1.5%; cases that linked to ≥1 epidemiologically linked case in the investigation were considered molecularly linked. Characteristics of cases initially linked through molecular analysis and already epidemiologically linked cases were compared using Fisher’s exact test. Results: As of 07/11/2018, the investigation included 129 persons, of whom 93 were initially epidemiologically linked. Of 108 investigation cases with a sequence, 96 were molecularly linked to ≥1 other case, forming four clusters of ≥5 cases (range in size: 5–55). Molecular analysis identified 36 persons not previously epidemiologically linked to the investigation; epidemiologic links were later identified for 4 cases. Molecularly linked and epidemiologically linked cases were similar with respect to age (majority aged <40 years), sex at birth (majority male), race/ethnicity (majority white, non-Hispanic), and transmission risk (vast majority with injection drug-use related risk) (all p-values >0.05). Conclusion: The presence of multiple molecular clusters among investigation cases suggests multiple introductions of HIV into the PWID community in NE MA, each with sustained transmission. The addition of molecular data expanded the number of persons linked to the investigation by 39%, improving prevention opportunities and highlighting the importance of molecular surveillance in HIV outbreak response.

1 University of British Columbia, Vancouver, BC, Canada, 2 BC Centre for Disease Control, Vancouver, BC, Canada Background: The incidence of syphilis has been increasing worldwide in the last 20 years, and has disproportionately impacted those living with HIV. Alongside this increase, several jurisdictions have reported increasing incidence of ocular syphilis (OS). If untreated or treatment is delayed, OS can lead to permanent blindness. We sought to characterize OS cases in British Columbia (BC), Canada, and identify associated factors. Methods: This case-control study compared OS cases to syphilis controls (1:4 ratio) diagnosed in BC between 01/2010 – 03/2018. Cases and controls were matched on age, sex, and date of syphilis diagnosis. Data were extracted via chart review of the provincial STI surveillance database. Potential risk factors were entered into the logistic regression model, where the dependent variable was OS. Variables were included in the final multivariable logistic regression model if significant at the 0.05 level. Results: 5681 syphilis cases were diagnosed in BC during the study period, where 61 (1.1%) had OS. Median age of OS cases was 47 years (interquartile range (IQR), 37-59). 88.5% of cases were male, among whom 55.7% identified as men who have sex with men. The most common ophthalmologic diagnoses in cases were panuveitis (44.3%), optic neuritis (19.1%), and retinitis (18.3%). Compared to controls, a greater proportion of cases had infectious syphilis (66.0% controls vs. 90.2% cases; P<0.001), and RPR titers >1:32 (26.2% controls vs. 88.5% cases; P<0.001). More than half of cases (50.8%) were HIV-positive at the time of syphilis diagnosis, compared to 25.8% of controls (P<0.001). Among HIV-positive individuals, 42.9% of cases had a suppressed viral load, compared to 79.7% of controls (P=<0.001). Cases also had higher HIV viral loads (P=0.011) and lower CD4 counts (P=0.014) than HIV-positive controls. The proportion of syphilis cases with ocular involvement increased significantly from 0.48% in 2010 to 2.99% in 2018 (P=0.04). Unadjusted and multivariable analysis findings are shown in Table 1. Infectious syphilis stages and HIV co-infection were statistically significantly associated with OS. Conclusion: OS incidence increased over the study period, both in absolute numbers and as a proportion of all syphilis cases, a finding consistent with other jurisdictions. These findings highlight the importance of vigilance for OS, particularly in those in the early stages of syphilis and those living with HIV, to avoid diagnostic and treatment delays.

Poster Abstracts

856 INCIDENT INFECTION IN HIGH-PRIORITY HIV MOLECULAR TRANSMISSION CLUSTERS

Joel O. Wertheim 1 , Nivedha Panneer 2 , Anne Marie France 2 , Neeraja Saduvala 3 , Alexandra M. Oster 2 1 University of California San Diego, San Diego, CA, USA, 2 CDC, Atlanta, GA, USA, 3 ICF International, Atlanta, GA, USA Background: CDC routinely analyzes HIV sequence data to identify priority clusters exhibiting recent and rapid transmission. Prevention efforts for clusters can include improving viral suppression among persons with diagnosed infection and finding undiagnosed infections; the relative importance of these two aims is unknown. We retrospectively identified priority clusters and determined the extent to which future, incident infections in these clusters were associated with presence of cases that, at the time of cluster prioritization, were diagnosed and viremic versus undiagnosed.

CROI 2019 334