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. Author manuscript; available in PMC: 2019 Nov 2.
Published in final edited form as: Lancet HIV. 2019 Sep 27;6(11):e800–e806. doi: 10.1016/S2352-3018(19)30227-9

Table 3:

Number of Infections in the Hypothetical Trial Distributed by the Four Strata of Infections Defined by Whether HIV Infections Would Occur or Not Between the TDF/FTC Only Stratum or Novel PrEP Agent Only

TDF/FTC** Only
PrEP LA* Only Averted Observed
Averted Δ1 Δ3 34
Observed Δ2 Δ4 91
44 81 125

Distribution of the 125 individuals who would become HIV+ in the absence of any PrEP in four principal strata. The numbers in each cell are latent.

1. Flexible stratum – those with infections prevented by offer of either TDF/FTC or PrEP LA, number of infections = Δ1

2. Pill-preferred stratum – those with infections prevented if offered TDF/FTC but not prevented if offered the PrEP LA, number of infections = Δ2

3. PrEP LA adopters stratum – those infected if offered TDF/FTC but prevented an offer of the PrEP LA, number of infections = Δ3

4. Unreached stratum – infected if provided TDF/FTC or PrEP LA. number of infections = Δ4

The shaded cells indicate strata in which infections could be prevented by the offer of the PrEP LA and/or TDF/FTC. The numbers in these cells are latent.

*

PrEP LA: non-daily and/or non-oral pre-exposure prophylaxis agent

**

TDF/FTC: daily oral tenofovir disoproxil fumarate and emtricitabine