Gentrification and declining Black population may be a key factor behind San Francisco’s declining HIV rates

San Francisco Pride Parade 2018. David Yu. Creative Commons licence.

Dramatic declines in HIV diagnoses in San Francisco have been attributed to testing, treatment and PrEP, but the declining Black population in the city is an unexamined factor, Dr Jade Pagkas-Bather of the University of Chicago and colleagues argue in the December issue of The Lancet HIV. There has been a 22% fall in San Francisco's Black population since 2000.

“We posit that the declining overall HIV incidence, including among White MSM [men who have sex with men], is not only explained by the use of treatment as prevention 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,” Pagkas-Bather says.

There are clear inequalities in access to treatment and prevention interventions in San Francisco:

  • 67% of Black people with HIV are linked to care, compared to 87% of White people.
  • 68% of Black people with HIV are virally suppressed, compared to 76% of White residents.
  • Six months after starting PrEP, 21% of Black MSM are still taking it, compared to 42% of White MSM.


treatment as prevention (TasP)

A public health strategy involving the prompt provision of antiretroviral treatment in people with HIV in order to reduce their risk of transmitting the virus to others through sex.

treatment cascade

A model that outlines the steps of medical care that people living with HIV go through from initial diagnosis to achieving viral suppression, and shows the proportion of individuals living with HIV who are engaged at each stage. 

virological suppression

Halting of the function or replication of a virus. In HIV, optimal viral suppression is measured as the reduction of viral load (HIV RNA) to undetectable levels and is the goal of antiretroviral therapy.

While there have been dramatic falls in new HIV diagnoses over the past decade, these have been concentrated in White MSM. Looking at the rate of diagnoses in the male population, it has fallen considerably in White men (from 118 per 100,000 men in 2010, to 27 per 100,000 men in 2018), but less so among Black men (from 191 per 100,000 men, to 145 per 100,000 men in the same time period). Taking into account the size of the population, the highest rates of HIV diagnoses in the city are in Black men and women.

The significant changes in the HIV epidemic in San Francisco have taken place at the same time as dramatic shifts in its population and economy. The cost of housing has soared, housing instability has increased and less affluent residents have moved out of the city. This has disproportionately affected Black people: compared to the year 2000, there were 18% fewer Black residents in 2010 and 22% fewer in 2019.

“Treatment as prevention and PrEP, when viewed through a socioeconomic lens, have led to positive outcomes for White MSM with access to steady employment, whereas Black MSM who do not have the same social or economic advantages have not been positively affected by the HIV treatment cascade,” say the authors. “When we examine trends suggesting that ending the HIV epidemic is well within reach, it is essential that we discuss for whom the epidemic is ending, and further examine the forces that perpetuate health inequities.”


Pagkas-Bather J et al. The last Black man with HIV in San Francisco: the potential role of gentrification on HIV getting to zero achievements. Lancet HIV 7: E853-856, 2020.


Full image credit: San Francisco Pride Parade 2018 by David Yu. Available at under a Creative Commons licence CC BY-NC 2.0.