If the proposed SB159 becomes law, then Californians at risk for HIV will be able to stop by a pharmacy and pick up their first 30 days of PrEP, or pre-exposure prophylaxis, without a doctor’s prescription. The state Senate passed the bill in May with near unanimous support, though, as the San Francisco Chronicle reports, the proposal does face opposition.

Senator Scott Wiener, a Democrat, proposed the bill so people could have easier access to the highly effective HIV prevention tablet. The bill does require pharmacists to first provide an HIV test and counseling, order lab tests to screen for kidney function and refer the patient to a primary care doctor to extend the PrEP prescription.

The bill is needed, Wiener told the paper, because “there are still way too many barriers.” People wanting PrEP often face long waits to find a doctor who will prescribe it, not to mention burdensome paperwork and stigma from health care providers.

The California Medical Association opposed the bill, saying it is “irresponsible” to provide PrEP without a prescription and the proper tests and counseling.

Republican Senator Brian Jones cast the lone vote against the bill. He said he’s concerned that PrEP can be “very hard on one’s kidneys and liver and therefore should be prescribed by a doctor.”

Wiener made headlines in 2014 when, as a San Francisco supervisor, he announced he was taking PrEP.

Currently, only one medicine—Gilead Sciences’ Truvada (tenofovir disoproxil fumarate/emtricitabine)—is approved as PrEP. By the end of this year, the Food and Drug Administration will likely approve an updated version called Descovy (tenofovir alafenamide/emtricitabine). Descovy includes a new version of tenofovir that is linked to better markers of kidney and bone health.

Scientists estimate that when Truvada is taken daily it reduces the risk of contracting HIV by 99% or more among men who have sex with men (MSM) and by 90% or more among women. (The risk reduction for women may very well be greater than 90%, but there isn’t sufficient research available to refine the estimate.)