A Novel Modeling Approach for Estimating Patterns of Migration into and out of San Francisco by HIV Status and Race among Men Who Have Sex with Men

Impact of COVID-19 Response on the HIV Epidemic in Men Who Have Sex With Men in San Francisco County: The Importance of Rapid Return to Normalcy

BACKGROUND

In response to the COVID-19 pandemic, San Francisco County (SFC) had to shift many nonemergency health care resources to COVID-19, reducing HIV control resources. We sought to quantify COVID-19 effects on HIV burden among men who have sex with men (MSM) as SFC returns to pre-COVID service levels and progresses toward the Ending the HIV Epidemic (EHE) goals.

SETTING

Microsimulation model of MSM in SFC tracking HIV progression and treatment.

METHODS

Scenario analysis where services affected by COVID-19 [testing, care engagement, pre-exposure prophylaxis (PrEP) uptake, and retention] return to pre-COVID levels by the end of 2022 or 2025, compared against a counterfactual where COVID-19 changes never occurred. We also examined scenarios where resources are prioritized to reach new patients or retain of existing patients from 2023 to 2025 before all services return to pre-COVID levels.

RESULTS

The annual number of MSM prescribed PrEP, newly acquired HIV, newly diagnosed, and achieving viral load suppression (VLS) rebound quickly after HIV care returns to pre-COVID levels. However, COVID-19 service disruptions result in measurable reductions in cumulative PrEP use, VLS person-years, incidence, and an increase in deaths over the 2020-2035 period. The burden is statistically significantly larger if these effects end in 2025 instead of 2022. Prioritizing HIV care/prevention initiation over retention results in more person-years of PrEP but less VLS person-years and more deaths, influencing EHE PrEP outcomes.

CONCLUSIONS

Earlier HIV care return to pre-COVID levels results in lower cumulative HIV burdens. Resource prioritization decisions may differentially affect different EHE goals.

Hepatitis C prevalence and key population size estimate updates in San Francisco: 2015 to 2019

BACKGROUND

In 2017, San Francisco's initiative to locally eliminate hepatitis C virus (HCV) as a public health threat, End Hep C SF, generated an estimate of city-wide HCV prevalence in 2015, but only incorporated limited information about population HCV treatment. Using additional data and updated methods, we aimed to update the 2015 estimate to 2019 and provide a more accurate estimate of the number of people with untreated, active HCV infection overall and in key subgroups-people who inject drugs (PWID), men who have sex with men (MSM), and low socioeconomic status transgender women (low SES TW).

METHODS

Our estimates are based on triangulation of data from blood bank testing records, cross-sectional and longitudinal observational studies, and published literature. We calculated subpopulation estimates based on biological sex, age and/or HCV risk group. When multiple sources of data were available for subpopulation estimates, we calculated an average using inverse variance weighting. Plausible ranges (PRs) were conservatively estimated to convey uncertainty.

RESULTS

The total number of people estimated to have anti-HCV antibodies in San Francisco in 2019 was 22,585 (PR:12,014-44,152), with a citywide seroprevalence of 2.6% (PR:1.4%-5.0%)-similar to the 2015 estimate of 21,758 (PR:10,274-42,067). Of all people with evidence of past or present infection, an estimated 11,582 (PR:4,864-35,094) still had untreated, active HCV infection, representing 51.3% (PR:40.5%-79.5%) of all people with anti-HCV antibodies, and 1.3% (PR:0.6%-4.0%) of all San Franciscans. PWID comprised an estimated 2.8% of the total population of San Francisco, yet 73.1% of people with anti-HCV antibodies and 90.4% (n = 10,468, PR:4,690-17,628) of untreated, active HCV infections were among PWID. MSM comprised 7.8% of the total population, yet 11.7% of people with anti-HCV antibodies and 1.0% (n = 119, PR:0-423) of those with untreated active infections. Low SES TW comprised an estimated 0.1% of the total population, yet 1.4% of people with HCV antibodies and 1.6% (n = 183, PR:130-252) of people with untreated active infections.

CONCLUSIONS

Despite the above-average number (2.6%) of people with anti-HCV antibodies, we estimate that only 1.3% (PR:0.6%-4.0%) of all San Francisco residents have untreated, active HCV infection-likely a reflection of San Francisco's robust efforts to diagnose infection among high-risk groups and initiate curative treatment with as many people as possible. While plausible ranges of infections are wide, these findings indicate that while the overall number of people with anti-HCV antibodies may have increased slightly, the number of people with active HCV infection may have decreased slightly since 2015. This estimate improves upon the 2015 calculations by directly estimating the impact of curative treatment citywide and in subgroups. However, more research is needed to better understand the burden of HCV disease among other subgroups at high risk, such as Blacks/African Americans, people with a history of injection drug use (but not injecting drugs in the last 12 months), people who are currently or formerly incarcerated, and people who are currently or formerly unhoused.

Hepatitis C Care Cascades for 3 Populations at High Risk: Low-income Trans Women, Young People Who Inject Drugs, and Men Who Have Sex With Men and Inject Drugs

BACKGROUND

To achieve elimination of hepatitis C virus (HCV) infection, limited resources can be best allocated through estimation of "care cascades" among groups disproportionately affected. In San Francisco and elsewhere, these groups include young (age ≤ 30 years) people who inject drugs (YPWID), men who have sex with men who inject drugs (MSM-IDU), and low-income trans women.

METHODS

We developed cross-sectional HCV care cascades for YPWID, MSM-IDU, and trans women using diverse data sources. Population sizes were estimated using an inverse variance-weighted average of estimates from the peer-reviewed literature between 2013 and 2019. Proportions of past/current HCV infection, diagnosed infection, treatment initiation, and evidence of cure (sustained virologic response at 12 weeks posttreatment) were estimated from the literature using data from 7 programs and studies in San Francisco between 2015 and 2020.

RESULTS

The estimated number of YPWID in San Francisco was 3748; 58.4% had past/current HCV infection, of whom 66.4% were diagnosed with current infection, 9.1% had initiated treatment, and 50% had confirmed cure. The corresponding figures for the 8135 estimated MSM-IDU were: 29.4% with past/current HCV infection, 70.3% diagnosed with current infection, 28.4% initiated treatment, and 38.9% with confirmed cure. For the estimated 951 low-income trans women, 24.8% had past/current HCV infection, 68.9% were diagnosed with current infection, 56.5% initiated treatment, and 75.5% had confirmed cure.

CONCLUSIONS

In all 3 populations, diagnosis rates were relatively high; however, attention is needed to urgently increase treatment initiation in all groups, with a particular unmet need among YPWID.

The last Black man with HIV in San Francisco: the potential role of gentrification on HIV getting to zero achievements

San Francisco was the first city in the USA to develop a Getting to Zero HIV elimination strategy. The cause of decreased HIV incidence has been attributed to the use of biomedical prevention methods, such as pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP). These strategies have benefitted White men who have sex with men (MSM), whose population has increased over the past decade. However, Black MSM in San Francisco continue to have higher HIV incidence and outmigration rates. We posit that the declining overall HIV incidence, including among White MSM, is not only explained by the use of TaSP and PrEP, but is also due to the declining Black population and rising HIV incidence among Black MSM, who have historically been more likely to acquire HIV due to structural, racial, and criminal justice-related factors than have White MSM.

Population-based methods for estimating the number of men who have sex with men: a systematic review

The objective of this systematic review was to summarise population-based methods (i.e. methods that used representative data from populations) for estimating the population size of men who have sex with men (MSM), a high-risk group for HIV and other sexually transmissible infections (STIs). Studies using population-based methods to estimate the number or percentage of MSM or gay men were included. Twenty-eight studies met the inclusion criteria. Seven studies used surveillance data, 18 studies used survey data, and six studies used census data. Sixteen studies were conducted in the US, five were conducted in European countries, two were conducted in Canada, three were conducted in Australia, one was conducted in Israel, and one was conducted in Kenya. MSM accounted for 0.03-6.5% of men among all studies, and ranged from 3.8% to 6.4% in the US, from 7000 to 39100 in Canada, from 0.03% to 6.5% in European countries, and from 127947 to 182624 in Australia. Studies using surveillance data obtained the highest estimates of the MSM population size, whereas those using survey data obtained the lowest estimates. Studies also estimated the MSM population size by dimensions of sexual orientation. In studies examining these dimensions, fewer people identified as MSM than reported experience with or attraction to other men. Selection bias, differences in recall periods and sampling, or stigma could affect the estimate. It is important to have an estimate of the number of MSM to calculate disease rates, plan HIV and STI prevention efforts, and to allocate resources for this group.

Getting to Zero San Francisco: A Collective Impact Approach

BACKGROUND

Building on several decades of innovative HIV prevention and treatment programming in San Francisco, in 2014, a small group of academic, civic, and community leaders launched Getting to Zero San Francisco, a city-wide consortium focused on getting to zero HIV infections, zero HIV-related deaths, and zero HIV stigma and discrimination.

SETTING

San Francisco city and county.

METHODS

The consortium operates under the principles of collective impact composed of 5 components: a common agenda, shared measurement, mutually reinforcing activities, continuous communication, and organization backbone. Two flagship initiatives are described: citywide scale-up of pre-exposure prophylaxis and rapid antiretroviral therapy upon diagnosis.

RESULTS

The number of new HIV diagnoses declined by over 50% from 399 to 197 from 2013 to 2018; the time from diagnosis to viral suppression decreased from 134 to 62 days during that period. However, continued racial/ethnic disparities in new HIV diagnoses and viral suppression rates point to the need for the Getting to Zero San Francisco committees to focus on racial/ethnic equity as a primary focus. Cisgender and transgender women, people who inject drugs, and people who are homeless also have lower viral suppression rates; ongoing initiatives are attempting to address these disparities.

CONCLUSION

A collective impact implementation strategy that operates by unifying municipal organizations toward a common goal was associated with citywide gains in reducing new HIV diagnosis and time to viral suppression in San Francisco. Formal evaluation of this strategy will help elucidate under which conditions this approach is most likely to succeed.

Estimation of new HIV diagnosis rates among high-risk, PrEP-eligible individuals using HIV surveillance data at the Metropolitan Statistical Area level in the United States

INTRODUCTION

New HIV diagnoses have fallen in the past decade due to increased HIV testing, earlier diagnosis, earlier antiretroviral treatment, improved linkage to care and engagement in care, and the recent increased uptake of pre-exposure prophylaxis (PrEP). We propose a novel method to compute the rate of new HIV diagnoses at the Metropolitan Statistical Area (MSA) level in the US to support the evaluation of comprehensive treatment and prevention efforts over time.

METHODS

The number of new HIV diagnoses, number of individuals with a PrEP indication and aggregated person-time exposed to PrEP during the years 2012 to 2017 were used to compute a new HIV diagnosis rate for people at risk of HIV excluding those already on PrEP for the 105 MSAs in the US with published HIV surveillance data. In our calculation of person-time with a PrEP indication, time-at-risk excluded time on PrEP and time after an HIV diagnosis. We used a multivariate Poisson regression model to estimate HIV diagnosis rates by year and location.

RESULTS

From 2012 to 2017, the aggregate HIV diagnoses rate among high-risk individuals with an indication for PrEP in the 105 MSAs decreased from 4.14 per 100 person-years (PY) (95% CI 4.10 to 4.19) to 3.26 per 100 PY (95% CI 3.22 to 3.30). For the 25 US MSAs that overlapped with an ongoing large randomized clinical trial of PrEP in men who have sex with men (MSM), the HIV diagnosis rate from 2012 to 2017 decreased from 4.86 per 100 PY (95% CI 4.80 to 4.93) to 3.61 per 100 PY (95% CI 3.56 to 3.66), a decline that was more rapid than in non-study MSAs (IRR for trial site 1.19, 95% CI 1.18 to 1.20).

CONCLUSIONS

We propose a model to estimate the background HIV diagnosis rate in people at risk for HIV and with a PrEP indication in US MSAs (excluding those on PrEP) using publically available surveillance data which can evaluate trends over time. Data generated using this methodology could be used by policy makers and local HIV prevention specialists to evaluate and monitor their prevention efforts for the population at risk in their communities.

Historical and Current Trends in the Epidemiology of Early Syphilis in San Francisco, 1955 to 2016

BACKGROUND

Seventeen years into a sustained epidemic, early syphilis (ES) rates in San Francisco (SF) are continuing to increase and the demographics of the affected population are changing. We provide a historical overview of ES in SF among men who have sex with men (MSM) and describe trends in the epidemiology and disease investigation outcomes.

METHODS

We examined data from the SF Department of Public Health's patient-based registry of integrated STD surveillance, clinical, and field investigation data to describe demographic and behavioral characteristics of ES cases, as well as outcomes of syphilis partner services (PS). χ Tests were performed to examine categorical differences across periods. Analysis of variance was used to examine differences in continuous variables.

RESULTS

In 2016, 1095 ES cases were reported among males in SF, a 219% increase from the 343 cases identified 10 years ago. Between 1996-1999 and 2010-2016, an increasing proportion of ES cases were among MSM younger than 25 years, nonwhite, and HIV negative (P < 0.05). A decreasing proportion of ES cases were assigned for PS, among whom a smaller proportion of reported sex partners were identified by name, resulting in an overall decline in the proportion of cases who had at least one named partner treated as a result of PS (Disease Intervention Rate) from 30.5 in 2000-2004 to 14.8 in 2010-2016.

CONCLUSIONS

Syphilis case rates continue to increase in SF and the epidemic is expanding beyond a core population. Additional resources and innovative prevention approaches are needed to reduce the burden of syphilis among MSM.

Estimated Population Size of Men Who Have Sex with Men, San Francisco, 2017

Current population size estimates of communities at risk for HIV are needed to adequately plan interventions and care. We update the estimated number of men who have sex with men (MSM) living in San Francisco. Multiple data sources and approaches, including population growth, registered HIV cases, wisdom of the crowd, and a published estimate on the proportion of adults who are MSM were used for estimation. The several estimates were synthesized into a final figure with acceptable bounds using a Bayesian method. We project 69,974 (acceptable bounds 65,523-74,323) MSM are living in San Francisco as of the beginning of 2017. The population of MSM in San Francisco has increased by 19.4% since 2014.

Incidence of first and second primary cancers diagnosed among people with HIV, 1985-2013: a population-based, registry linkage study

BACKGROUND

Cancer survivors are at increased risk for subsequent primary cancers. People living with HIV are at increased risk for AIDS-defining and non-AIDS-defining cancers, but little is known about their risk of first versus second primary cancers. We identified first and second primary cancers that occurred in above population expected numbers among people diagnosed with HIV in San Francisco, and compared first and second cancer incidence across five time periods that corresponded to important advances in antiretroviral therapy.

METHODS

In this population-based study, we used the San Francisco HIV/AIDS case registry to identify people aged 16 years and older who were diagnosed with HIV/AIDS in San Francisco (CA, USA) between Jan 1, 1990, and Dec 31, 2010. We computer-matched records from the registry with the California Cancer Registry to identify primary cancers diagnosed between Jan 1, 1985, and Dec 31, 2013. We calculated year, age, sex, and race adjusted standardised incidence ratios with exact 95% CIs and trends in incidence of first and second AIDS-defining and non-AIDS-defining cancers from 1985 to 2013.

FINDINGS

Of the 22 623 people diagnosed with HIV between Jan 1, 1990, and Dec 31, 2010, we identified 5655 incident primary cancers. We excluded 48 cancers with invalid cancer sequence numbers and 1062 in-situ anal cancers, leaving 4545 incident primary cancers, comprising 4144 first primary cancers, 372 second primary cancers, 26 third primary cancers, and three fourth or later primary cancers. First primary cancer standardised incidence ratios were elevated for Kaposi sarcoma (127, 95% CI 121-132), non-Hodgkin lymphoma (17·2, 16·1-18·4), invasive cervical cancer (8·0, 4·1-11·9), anal cancer (46·7, 39·7-53·6), vulvar cancer (13·3, 6·1-20·6), Hodgkin's lymphoma (10·4, 8·4-12·5), eye and orbit cancer (4·2, 1·4-6·9), lip cancer (3·8, 1·3-6·2), penile cancer (3·8, 1·4-6·1), liver cancer (3·0, 2·3-3·7), miscellaneous cancer (2·3, 1·7-3·0), testicular cancer (2·0, 1·4-2·6), tongue cancer (1·9, 1·1-2·7), and lung cancer (1·3, 95% CI 1·1-1·6). Second primary cancer risks were increased for Kaposi sarcoma (28·0, 95% CI 20·2-35·9), anal cancer (17·0, 10·2-23·8), non-Hodgkin lymphoma (11·1, 9·3-12·8), Hodgkin's lymphoma (5·4, 1·1-9·7), and liver cancer (3·6, 1·4-5·8). We observed lower first primary cancer standardised incidence ratios for prostate cancer (0·6, 95% CI 0·5-0·7), colon cancer (0·6, 0·4-0·8), and pancreatic cancer (0·6, 0·3-1·0), and lower second primary cancer standardised incidence ratios for testicular cancer (0·3, 0·0-0·9), kidney cancer (0·4, 0·0-0·9), and prostate cancer (0·6, 0·2-0·9). First and second primary AIDS-defining cancer incidence declined, and second primary non-AIDS-defining cancer incidence increased over time.

INTERPRETATION

Because of an increased risk for both first and second primary cancers, enhanced cancer prevention, screening, and treatment efforts are needed for people living with HIV both before and after initial cancer diagnosis.

FUNDING

University of California San Francisco and US Centers for Disease Control and Prevention.

Estimated hepatitis C prevalence and key population sizes in San Francisco: A foundation for elimination

BACKGROUND

Initiated in 2016, End Hep C SF is a comprehensive initiative to eliminate hepatitis C (HCV) infection in San Francisco. The introduction of direct-acting antivirals to treat and cure HCV provides an opportunity for elimination. To properly measure progress, an estimate of baseline HCV prevalence, and of the number of people in various subpopulations with active HCV infection, is required to target and measure the impact of interventions. Our analysis was designed to incorporate multiple relevant data sources and estimate HCV burden for the San Francisco population as a whole, including specific key populations at higher risk of infection.

METHODS

Our estimates are based on triangulation of data found in case registries, medical records, observational studies, and published literature from 2010 through 2017. We examined subpopulations based on sex, age and/or HCV risk group. When multiple sources of data were available for subpopulation estimates, we calculated a weighted average using inverse variance weighting. Credible ranges (CRs) were derived from 95% confidence intervals of population size and prevalence estimates.

RESULTS

We estimate that 21,758 residents of San Francisco are HCV seropositive (CR: 10,274-42,067), representing an overall seroprevalence of 2.5% (CR: 1.2%- 4.9%). Of these, 16,408 are estimated to be viremic (CR: 6,505-37,407), though this estimate includes treated cases; up to 12,257 of these (CR: 2,354-33,256) are people who are untreated and infectious. People who injected drugs in the last year represent 67.9% of viremic HCV infections.

CONCLUSIONS

We estimated approximately 7,400 (51%) more HCV seropositive cases than are included in San Francisco's HCV surveillance case registry. Our estimate provides a useful baseline against which the impact of End Hep C SF can be measured.

Distribution of Behavioral Patterns Before Infection Among San Francisco Men Who Have Sex With Men Newly Infected With HIV in 2014

BACKGROUND

Despite continued reductions in the number of HIV cases reported among San Francisco men who have sex with men (MSM) and the HIV-prevention potential offered by pharmaceutical tools such as pre-exposure prophylaxis (PrEP), there are uncertainties, particularly given reported decreases in consistent condom use. A key uncertainty is what groups of MSM should be targeted. This study estimates the distribution of behavioral patterns before infection among San Francisco MSM newly infected with HIV in 2014.

METHODS

We used a novel modeling approach. The approach uses estimates from the National HIV Behavioral Surveillance System for MSM, the Medical Monitoring Project, 2 trials of PrEP, and a meta-analysis of per-act risks of HIV infection.

RESULTS

The modeling study suggests that 76% of newly HIV-infected MSM in 2014 were individuals with no discernible strategy in the 6 months before infection: that is, they had condomless receptive anal intercourse with one or more partners not perceived to be HIV uninfected. An estimated 7% of newly infected MSM were serosorters before infection.

CONCLUSIONS

Prevention efforts in San Francisco must reach HIV-uninfected MSM with no discernible behavioral strategy, a group that constitutes 8% of HIV-uninfected MSM in the city. Our study suggests that if all HIV-uninfected, San Francisco MSM with no discernible strategy had been on PrEP in 2014, there would have been 70% fewer HIV infections among San Francisco MSM. Uncertainty analysis suggests that PrEP's impact may be maximized by encouraging PrEP persistence and concomitant reductions in sexual risk behaviors.