The U.S. Food and Drug Administration has approved a highly effective HIV prevention drug that outperforms oral medications in stopping HIV transmission.

Developed by Gilead Sciences, the drug lenacapavir — marketed as Yeztugo — requires just one injection every six months.

Like other PrEP drugs, if enough of the medication is present when a person is exposed to HIV, it can prevent the virus from taking hold and causing a lifelong infection. Because lenacapavir is long-acting, it requires only two injections per year.

Past studies have found lenacapavir to be 89% more effective than oral PrEP at preventing HIV transmission among gay, bisexual, and transgender individuals — and 96% more effective than Gilead estimated would have been expected had participants received no PrEP at all.

In a similar trial among cisgender women in sub-Saharan Africa, none of the participants who received Yeztugo contracted HIV.

The injectable drug is believed to be significantly more effective than oral PrEP because it eliminates the challenges of adhering to a daily pill regimen, which requires taking medication at the same time each day to maintain protection.

“This is the single best opportunity in 44 years of HIV prevention,” Mitchell Warren, executive director of the HIV advocacy nonprofit group AVAC, told NBC News.

Scientists hope the medication will help accelerate the stubbornly slow decline of HIV transmission in the United States — a rate much lower than in other developed nations.

Among the reasons cited for that disparity: the lack of a national health care system or sexual-health clinic network, fragmented and underfunded public health systems, state laws criminalizing HIV exposure, lack of insurance coverage, and mistrust of health providers, especially among communities of color.

“This is a remarkable step forward, but science alone doesn’t save lives — access does,” Paul Kawata, executive director of the HIV advocacy organization, NMAC, said in a statement. “Without a strong HIV prevention infrastructure, long-acting PrEP like lenacapavir won’t reach the communities who need it most.”

The barriers to accessing lenacapavir are many in number and daunting, beginning with cost. Each injection reportedly costs $14,109, or the equivalent of $2,352 per month — a pricey amount to pay out of pocket for the average person.

The barriers to accessing lenacapavir are numerous and daunting, starting with cost.

Each injection reportedly costs $14,109 — meaning an annual cost of more than $28,000, or roughly $2,350 per month when averaged out — a steep price for most people to pay out of pocket.

While insurance could potentially cover the cost of the drug, it is unclear whether insurers will choose to do so. For instance, insurers could decide to only cover oral PrEP medications, including the cheaper, generic version of Truvada pills, or they could impose higher copays for lenacapavir, Elizabeth Kaplan, the director of health care access at Harvard Law School’s Health Law and Policy Clinic, told NBC News.

While insurance could potentially cover the cost of the drug, it remains unclear whether insurers will do so. Some may choose to cover only oral PrEP medications, such as the cheaper generic version of Truvada, or impose higher copays for lenacapavir, Elizabeth Kaplan, director of health care access at Harvard Law School’s Health Law and Policy Clinic, told NBC News.

Further complicating insurance coverage is an upcoming Supreme Court decision that could strike down a provision of the Affordable Care Act allowing a health task force to require insurers to cover various preventive health interventions or screenings at no cost.

Such a ruling would effectively give insurers the green light to raise copays for PrEP — and any increase in out-of-pocket costs would likely discourage many from pursuing the treatment.

Additionally, the Trump administration has proposed cutting domestic HIV funding by $1.5 billion — or 35% — while also shuttering the Centers for Disease Control and Prevention’s HIV Prevention Division as part of broader efforts to slash government spending.

Because much of the CDC’s HIV prevention and surveillance budget is distributed through grants to state and local health departments and nonprofits, such cuts would likely hamper efforts to educate patients and doctors about lenacapavir or make the drug more widely available.

Yet another hurdle is the issue of adherence. Inconsistent use of PrEP lowers its effectiveness, and two recent studies found that fewer than half of oral PrEP users remained adherent for more than six months. While there is hope that injectable lenacapavir will improve adherence, there is not yet scientific proof to confirm this.

Additionally, another injectable form of PrEP — Apretude, produced by ViiV Healthcare, which only required patients to schedule four visits per year to receive injections — has failed to gain traction among at-risk populations, with only 21,000 taking advantage of the preventative treatment.

Another injectable form of PrEP — Apretude, produced by ViiV Healthcare — requiring only four clinic visits per year, has failed to gain traction among at-risk populations, with just 21,000 people utilizing the treatment.

MISTR, the telehealth company that focuses primarily on providing access to PrEP to at-risk populations, including members of the LGBTQ community, has said it intends to connect users to in-person injection services. The company has lined up providers in seven historically or predominantly LGBTQ neighborhoods in different cities — West Hollywood, California; San Francisco’s The Castro neighborhood; New York’s Hell’s Kitchen neighborhood; Wilton Manors, Florida; Chicago’s Northalsted neighborhood; Dallas’ Oaklawn neighborhood; and Las Vegas — to administer the shots.

MISTR, a telehealth company focused on providing PrEP access to at-risk populations, including the LGBTQ community, says it will connect users to in-person injection services.

The company has lined up providers in seven historically or predominantly LGBTQ neighborhoods — West Hollywood, California; San Francisco’s Castro; New York’s Hell’s Kitchen; Wilton Manors, Florida; Chicago’s Northalsted; Dallas’ Oaklawn; and Las Vegas — to administer the shots.

MISTR plans to connect patients outside those hubs with a network of providers who can administer the injections, regardless of insurance status.

“Lenacapavir is a true game-changer in HIV prevention,” Tristan Schukraft, CEO of MISTR, said in a statement. “Just two injections a year — that’s it. It’s discreet, effective, and finally makes long-term PrEP adherence simple and practical for more people.”