PrEP: Third FDA Anniversary

Three years ago today the FDA approved Truvada as a daily HIV preventive. Since then PrEP has remained controversial. Powerful naysayers like the AIDS Healthcare Foundation run anti-PrEP ads in a major publications while other HIV/AIDS groups and health departments in major US cities vigorously promote PrEP for at-risk populations. In another PrEP promotion, the hook-up app Scruff is today supporting PrEP Action Day on social media. Meanwhile, the guy in the clip below delivers a raunchy anti-PrEP rant.

VICE: The Truvada Revolution

VICE has launched a three-part series titled The Truvada Revolution. 

A drug called Truvada is the first the FDA-approved means of preventing HIV infection. If an HIV-negative person takes the pill every day, they're nearly 99 percent protected from contracting the virus. Controversy continues to surround the broad uptake of Truvada, but the landscape of safer sex and HIV-prevention changes fundamentally from this point forward—particularly within the gay male community, the population hardest hit by HIV in America. In this episode of VICE Reports, VICE explores the future of the Truvada and its revolutionary impact on ending HIV/AIDS.

Near the end of the clip below, AIDS Healthcare Foundation head and anti-PrEP activist Michael Weinstein talks about his campaign against the use of Truvada as a daily HIV preventive. See Part 2 and Part 3. The series was produced and directed by my pal (and JMG reader) Eric Leven.

STUDY: PrEP Reaches Max Effectiveness Against HIV After One Week Of Dosing

Poz.com reports:

Daily Truvada as pre-exposure prophylaxis (PrEP) against HIV takes five to seven days to reach top estimated effectiveness among men who have sex with men (MSM). High levels of protection are maintained for perhaps a week after the last dose. According to levels of drug detected in peripheral blood mononuclear cells (PBMCs), and comparisons of those results to drug levels estimated in previous research to correspond to varying degrees of protection against HIV, one day on PrEP led to a 75 to 91 risk reduction, three days meant a 95 to 97 percent risk reduction, and five and seven days translated to a 98 to 99 percent risk reduction. The presumed risk reduction stayed higher than 90 percent for seven days after the last dose. Although the study included female participants, it was not meant to estimate how well PrEP dosing protects them or other groups, just MSM. The iPrEx study used as the reference point for Truvada’s effectiveness at various concentrations in PBMCs was only conducted among MSM and trans women.

Hit the link for more about the study.

Insurance Company Ends PrEP Coverage UPDATE: Company Reverses Decision

Poz.com reports:

Assurant Health, a national company specializing in health insurance coverage for individuals and small businesses, will no longer cover the med Truvada as pre-exposure prophylaxis (PrEP) to prevent contracting HIV. Several Assurant customers who had been taking Truvada (comprising the antiretrovirals tenofovir and emtricitabine) as PrEP were recently notified that the insurer would end coverage of the med in July. “Prophylactic treatment is not a covered benefit as listed in the Exclusion Section of your member contract,” read one customer’s notice (see below). “As a courtesy we will allow two additional months of prescription coverage for your Truvada prescription. This means you will continue to receive prescription drug card benefits for Truvada at CVSC Specialty Pharmacy until July 1, 2015.”

Truvada as a daily HIV preventive has been approved by the FDA and endorsed by the CDC. Last week the parent company of Assurant revealed that next year it will either sell or shut down the insurer because they can no longer refuse to cover high-risk patients due to the implementation of the Affordable Care Act.

UPDATE: This just in: "Hello, I wanted to provide the following updated information to you. Here is our statement. We are reversing our decision and will be reaching out to policyholders who received the letter. Thank you, Mary Hinderliter, Vice President, Assurant Health."

Short Film on PrEP: Unwrapping Truvada

Featuring Dan Savage, Cleve Jones, San Francisco Supervisor Scott Wiener, and AIDS Healthcare Foundation head Michael Weinstein.

(Tipped by JMG reader Eric)

New PrEP Study Shows 86% Effectiveness For Before/After Sex Dosing Schedule

Via the Associated Press:

For the first time, a study shows that a drug used to treat HIV infection also can help prevent it when taken before and after risky sex by gay men. The results offer hope of a more appealing way to help prevent the disease beyond taking daily pills and using condoms, although those methods are still considered best. The study, done in France and Canada, is the first to test "on demand" use of Truvada, a pill combining two AIDS drugs, by people planning to have risky sex. The uninfected men who took it were 86 percent less likely to get HIV compared to men given dummy pills.

"That impressed me," Dr. Scott Hammer said of the size of the benefit. He is an AIDS specialist at Columbia University in New York and heads the Retrovirus Conference going on in Seattle, where the results were discussed Tuesday. Daily Truvada pills are used now to prevent HIV infection in people at high risk for it, and studies show the drug helps even when some doses are skipped. Health officials have been leery of billing it as a "chemical condom" out of fear that people will not use the best prevention methods, but many won't use condoms all the time or take daily pills.

The study of Gilead Science's Truvada was led by the French national HIV research agency. Men were given fake or real Truvada and told to take two pills from two to 24 hours before sex, a third pill 24 hours later, and a fourth pill 48 hours after the first dose. The men also were given condoms and disease prevention counseling.

An important note of caution from the CDC:

Since available data suggest that men in this study were taking PrEP an average of three to four days per week, CDC cautions that researchers do not yet know if this regimen will work among MSM who have sex less frequently and would therefore be taking PrEP less often.

It is not known whether the regimen will work if taken only a few hours or days before sex, without any buildup of the drug from prior use. Studies suggest that it may take days, depending on the type of sexual exposure, for the active drug in PrEP to build up to an optimal level for preventing HIV infection.

There are also no data on how effective this regimen would be for heterosexual men and women and injection drug users or on adherence to this relatively complex PrEP regimen outside a trial setting. CDC continues to recommend only daily use of PrEP, as approved by the FDA. IPERGAY findings combined with other recent research suggests that even with less than perfect daily adherence, PrEP may still offer substantial protection if taken consistently.

GMHC To Host PrEP Rally

Gay Men's Health Crisis will host a "PrEP Rally" on February 2nd to discuss the use of Truvada as a daily HIV preventive. From their Facebook event page: "Heard about PrEP & Truvada? Not sure if it's right for you? Not sure how to get it with or without insurance? Let's clear up some rumors and get the facts! Join our panel of experts as we bring you up to speed on the latest information, facts, controversies, and answer your burning questions." 

Among the panelists is a representative from Gilead, the maker of Truvada. To my knowledge, Gilead has not yet countered the AIDS Healthcare Foundation's many anti-Truvada ads with a print campaign of their own, although they do have a "risk evaluation and mitigation strategy" website which stipulates that Truvada "does not replace existing prophylaxis strategies." Truvada's use as an HIV preventive has been endorsed by almost all HIV/AIDS groups and the health departments of several major cities. Last year the CDC issued its own usage guidelines.

New Anti-PrEP Ad From AIDS Healthcare

The AIDS Healthcare Foundation continues its campaign against PrEP and Truvada today with the above open letter to the CDC which is being published in major newspapers. Writing for the New York Times, Josh Barro notes that the AHF is fighting this battle alone:

“There’s no large controversy; there is one loud voice,” said Charles King, the president of the H.I.V. nonprofit Housing Works and a co-chairman of an anti-H.I.V. task force appointed by Gov. Andrew Cuomo of New York. Mr. King called the A.H.F. ad “a direct attack on New York State’s efforts to end AIDS as an epidemic.” The growing pro-PrEP chorus includes government bodies like the World Health Organization and the Centers for Disease Control and Prevention; various state and local health departments, including in New York and San Francisco; and most H.I.V.-related nonprofits that have taken a stance. Mr. Cuomo has made PrEP one of three planks in his anti-AIDS plan.

Mr. Weinstein’s vociferous opposition to PrEP has made him perhaps the most hated man in the AIDS business. “I consider him a menace to H.I.V. prevention,” said Peter Staley, a veteran activist who also serves on the Cuomo task force. James Loduca, the vice president for public affairs at the San Francisco AIDS Foundation, compared him to a “climate-change denialist.” For his part, Mr. Weinstein insists he’s not really alone. He says “a majority” of H.I.V. experts he speaks with privately agree with his view that PrEP is an ineffective public health intervention, but they do not want to talk publicly.

Embiggen the image to read the text.

New PrEP Study Upends Edict That Med Must Be Taken Daily To Be Effective

Gus Caims reports at AIDS Map:

In an extraordinary development, a second European scientific trial of pre-exposure prophylaxis (PrEP) has had its randomised phase closed early due to high effectiveness, just two weeks after the UK PROUD trial did exactly the same thing. The investigators of the IPERGAY trial, which has six sites in France and one in Canada, announced today a “Significant breakthrough in the fight against HIV and AIDS” because IPERGAY had successfully demonstrated the effectiveness of its PrEP regimen.

IPERGAY’s early closure is significant not only because it adds confirmation that PrEP can be highly effective, but because it was testing an innovative, intermittent (“on-demand”) PrEP regimen. In this study, participants did not take PrEP daily, but only when they anticipated having sex. The regimen involved taking two pills of Truvada (tenofovir + emtricitabine) twelve hours before anticipated sex and then, if sex happened, two separate one-pill doses the following day. This extends the versatility of PrEP and provides an alternative regimen to daily dosing.

IPERGAY was run by the French national AIDS research institute, ANRS, and began in February 2012. It randomised gay men at high risk of HIV infection to the Truvada regimen or to a placebo – a protocol that caused some controversy among activists who felt studies such as iPrEx had already demonstrated that PrEP worked. All participants were also offered a package of measures including “personalised and frequent” counselling, repeated HIV testing, screening and treatment for other sexually transmitted infections, hepatitis B vaccination, condoms and lubricant. At the time of closure of its randomised phase, the trial had approximately 400 participants.

Perhaps it should go without saying, but Truvada users should remain on their daily dosing regimen for the time being and until after this study's results have been replicated and endorsed by multiple major HIV/AIDS experts. That said, the prospect of an intermittent dosing regimen versus a lifetime daily dosing schedule of a medication whose long-term side effects remain unclear - that is indeed appealing. However it seems that "anticipating sex," for many gay men, would require daily dosing anyway. I vaguely recall that sex can sometimes happen without anticipation, certainly much faster than 12-hours notice.

UPDATE: Via renowned activist Peter Staley's Facebook page, the chart below indicates that a 12-hour notice is not required. The first notation reads: "1st dose: 2 tablets, Max. 24h - Min 2h before first sexual relation."

UDPATE II: The source of the chart above and much more about this study can be found here.

SAN FRANCISO: Supervisors Create Fund To Educate Residents About PrEP

Via Mission Local:

In a 10 to 1 vote, the San Francisco Board of Supervisors passed legislation to allocate $301,600 from the city’s general fund toward educating San Francisco residents about the HIV-prevention pill Truvada. Now “health navigators,” who will be commissioned by the San Francisco Department of Public Health, will help patients access the drug — whether they have private insurance, Medi-Cal or patient assistance programs through the drug’s manufacturer. Supervisor David Campos, co-author of the legislation, asked for his colleagues’ support, adding, “San Francisco is already a sanctuary city, so let’s please make it a sanctuary city from HIV.” HIV is the virus that causes AIDS. With the passage of the legislation, the San Francisco Supervisors have initiated their plan to help eliminate new cases of HIV in the city by making the health navigators more culturally competent as well. Truvada is an antiviral medication that is taken once-daily in order to prevent new HIV infections in those at highest risk of contracting the disease.

(Tipped by JMG reader Eric)

Human Rights Campaign Endorses PrEP

Via the Associated Press:

The largest U.S. gay-rights organization Saturday endorsed efforts to promote the use of a once-a-day pill to prevent HIV infection and called on insurers to provide more generous coverage of the drug. Some doctors have been reluctant to prescribe the drug, Truvada, on the premise that it might encourage high-risk, unprotected sexual behavior. However, its preventive use has been endorsed by the Centers for Disease Control and Prevention, the World Health Organization, and many HIV/AIDS advocacy groups

The Human Rights Campaign, which recently has been focusing its gay-rights advocacy on same-sex marriage and anti-discrimination issues, joined those ranks with the release of a policy paper strongly supporting the preventive use of Truvada. It depicted the drug as "a critically important tool" in combatting HIV, the virus that causes AIDS. "HRC does not take this position lightly," the policy paper said. "We recognize there is still ongoing debate ... and that there are those out there who will disagree with our stance."

The AIDS Healthcare Foundation denounced HRC's move and said that it plans to expand its anti-PrEP media campaign.

CDC Launches PrEP Hotline For Doctors

After reports that relatively few healthcare providers are prescribing Truvada as a daily HIV preventive, the CDC has launched a free hotline to answer their questions.

PrEPline is aimed toward physicians, nurse practitioners and physician assistants providing primary care to uninfected patients with high risk. The phone service is staffed by experienced clinicians and offers written and online checklists, guidelines and other informational materials. “PrEP is a powerful HIV prevention tool that has the potential to alter the course of the US epidemic if its use is increased among patients who are at substantial risk for HIV infection,” Dawn Smith, MD, MPH, of the Division of HIV/AIDS Prevention at the CDC, said in a statement. “By offering free, expert advice based on the new federal guidelines to clinicians, including those who may not have experience prescribing antiretroviral medications, PrEPline will ensure clinicians across the country have timely access to the information they need to get PrEP into the hands of their patients.” PrEPline is open to calls from 11 a.m. to 6 p.m. EST, Monday through Friday, and can be reached at 855-448-7737.

PrEP has been recommended for uninfected bisexual and gay men by the CDC, the World Health Organization, and almost all HIV/AIDS organizations. However the AIDS Healthcare Foundation, which bills itself as the "largest community-based HIV/AIDS medical provider in the nation," continues to fiercely oppose PrEP via print and online campaigns. AHF president Micheal Weinstein has characterized Truvada as a "party drug" for promiscuous barebackers and has pointed out that strict adherence to a daily dosing regimen is critical to the drug's efficacy. (Tipped by JMG reader Eric)

NYC Takes PrEP Campaign To Grindr

The New York City Department of Health has launched a PrEP campaign on Grindr, Scruff, and social media sites. And of course, the ever combative AIDS Healthcare Foundation is furious.

A stigma persists that Truvada is a "party pill" -- an attitude shared by some doctors who scold patients about their sexual practices and won't prescribe it, said Anthony Hayes, a spokesman for the Gay Men's Health Crisis, which backs PrEP. The journal Clinical Infectious Diseases found that 74 percent of surveyed clinicians back PrEP, yet only 9 percent had prescribed it. Enter Dr. Demetre Daskalakis, the health department's new assistant commissioner for HIV/AIDS control and prevention. Previously a top AIDS doctor at Mount Sinai Hospital, he is a self-described "gay health warrior." "There's not a lot of doctors who can say, 'I've done thousands of HIV [blood] tests with my hands in dark sex clubs,' " he said. "I have done that."

The city is spending about $500,000 to encourage PrEP, with outreach to doctors and ads on Facebook, Twitter and hookup apps like Grindr and Scruff. Says one ad: "Share the Night, Not HIV." Among those in Daskalakis' focus: young black and Latino men, who studies find at higher risk because of the amount of the virus in the population and health care disparities. The city's PrEP push is misguided, said Michael Weinstein, head of the AIDS Healthcare Foundation, which serves 200,000 patients globally. "The first order of business in medical ethics is 'do no harm,' and what the New York City Health Department's doing is doing harm, because there are people who are going to take this drug intermittently, who are going to think they're protected, who are going to not be protected," Weinstein said.

Fairly strict adherence to daily dosing is critical to maintaining Truvada's effectiveness as a preventive.

Andrew Sullivan Writes About PrEP

"Here are your options: the blue pill or the red pill. Take the one-pill-a-day Truvada and never get HIV; take the often one-pill anti-retroviral pill, and you will never give someone HIV. To make doubly sure, you can always use a condom. Except almost every man who ever had sex hates condoms – and, unlike a pill you take every day, wearing a condom means making a decision in the middle of sexual desire and passion when your rational self is at its weakest. [snip] The discourse around this new breakthrough has long been about risks and expense and compliance and how to make sure men don’t get too promiscuous again. And all that has its place. But we fail to understand this moment if we do not understand the liberation that comes with ridding gay sex of the terror and stink of death, the liberation that comes with leaving a world where another man – before he can be anything to you – has to be put in a 'positive' or 'negative' box. Sex is about intimacy; it is about love; it is about relief. And for the first time since the early 1980s, we have a chance to rid it of fear. Why are we not rushing to embrace this? What is still preventing us from becoming collectively a force for love and friendship that is no longer limned with terror?" - Andrew Sullivan, writing for his site.

SF Might Distribute Free Truvada

San Francisco might become the world's first city to distribute free Truvada as a daily HIV preventive. Via Huffington Post:

Supervisor David Campos announced plans to make PrEP cheap or free for residents in statements on his Facebook. “This coming Tuesday, I will introduce a measure to allocate funds for navigators to educate patients about PrEP, and provide subsidies to San Franciscans who cannot afford the life saving medication,” he said Thursday, a day after suggesting San Francisco can set a national example: “By making PrEP available to all regardless of income, we could set the tone for the rest of the country in how to effectively eradicate a disease that claimed the lives of so many of our loved ones.” At the rally on Thursday, [Supervisor Scott] Wiener emphasized how prevalent HIV remains, pointing to statistics that show there are 400 new HIV infections a year in San Francisco, 50,000 nationwide and more than 2 million around the world. “I'm sick of meeting people 18, 19, 20, 21 years old who are [HIV] positive. We know that this is not necessary,” he said. “I think a lot of times, especially in the mainstream, there’s this view that somehow HIV is over, that the epidemic is somehow resolved, that everything is okay, and we know that that’s not true."

Most major HIV/AIDS organizations have endorsed the use of Truvada but all caution that adherence to the daily regimen is critical to maintaining its preventive function.

SF Supervisor: I'm On Truvada

San Francisco Supervisor Scott Wiener has become the first elected official to publicly disclose that he is taking Truvada as a daily HIV preventive. Josh Barro reports at the New York Times:

“A much larger segment of gay men should be taking a close look at PrEP,” Mr. Wiener, who represents the same Castro-based district once held by Harvey Milk, said in an interview on Wednesday. “I hope that my being public about my use of PrEP can help people take a second look at it.” According to data from the San Francisco Department of Public Health, there were 359 new H.I.V. infections in the city in 2013, 86 percent of them among men who have sex with men. Authorities including the World Health Organization and San Francisco’s health department say they believe that PrEP is a good strategy to cut new infections among gay men. But PrEP has been slow to catch on. According to data from the city, there were fewer than 1,000 active prescriptions for Truvada as PrEP in San Francisco at the end of 2013.

The Board of Supervisors will hold a meeting today to discuss increasing the number of people taking Truvada.

AHF Launches Anti-PrEP Ad Campaign

The combative and controversial AIDS Healthcare Foundation is launching a print ad campaign against the use of Truvada as a daily HIV preventive. Via press release:

AHF’s ‘PrEP Facts’ ad campaign educating the public about adherence issues and PrEP initially started running this week in a few newspapers, magazines and online outlets in California and will continue and expand to six outlets in California and five news outlets in South Florida over the next week. AHF’s campaign also comes on the heels of recent—and what AHF believes are misguided—recommendations by both the Centers for Disease Control (CDC) and World Health Organization (WHO) for the widespread scale up and implementation of the problematic HIV prevention strategy.

“The eight major studies show the scientific data do not support the large-scale use of Truvada as a community-wide public health intervention to prevent transmission of HIV,” said Michael Weinstein, President of AIDS Healthcare Foundation. “Medication adherence is the primary problem: Even in carefully monitored clinical trials, in which people were counseled monthly, had blood samples drawn and were even paid to participate, many study participants simply did NOT take Truvada every day as prescribed. As such, we want the public to know that the government-sanctioned widespread scale up of PrEP appears to be a public health disaster in the making.”

The ads will run in numerous LGBT, mainstream, and alternative papers including Frontiers, South Florida Gay News, Los Angeles Daily News, Miami New Times, Hotspots, Oakland Post, and Florida Agenda.

LOS ANGELES: Porn Shoot Permits Drop 90% After Condom Use Mandate

In November 2012, Los Angeles County voters approved a bill that mandates the use of condoms in all porn video shoots. The Associated Press reports today that local applications for porn filming permits dropped by more than 90% last year. But that doesn't mean that condom-less filming isn't still taking place.

So where are those hundreds of films available for instant download on the Internet coming from? Many are still coming from right here, say industry officials, acknowledging that when Los Angeles County voters cracked down on filmmakers in November 2012 with an ordinance requiring that actors use condoms, quite a few filmmakers went underground. "A lot are simply shooting in out-of-the-way places where they won't be caught," says Mark Kernes, senior editor at Adult Video News, which tracks industry trends. "Normally it's in people's homes who are willing to rent them out for a day. Sometimes it's out in the woods. There are vacation cabins far away from anything that you can shoot a movie at."

Others have traveled outside of Los Angeles County, either to neighboring counties or sometimes even out of state. Diane Duke, executive director of the Free Speech Coalition, an industry advocacy group, said she knows of a handful that have moved to Las Vegas, although none want to be mentioned by name for fear of bringing condom activists after them. Although a few porn producers do require that actors use condoms, the majority do not, saying fans have made it clear they don't want to see them. Wherever the filmmakers are working now, only 20 have applied for permits so far this year, according to Film LA, which issues them. Last year 40 adult filmmakers took out permits, compared with 485 in 2012, the last year before the ordinance took effect.

RELATED: The Los Angeles County ordinance was spearheaded by the combative and controversial AIDS Healthcare Foundation. Today the AHF issued a press release declaring that it has filed an OSHA complaint against a San Francisco-based porn company that is filming in Nevada.

“Under the guise of his various Kink and Kink.com, adult film businesses and brands, owner Peter Acworth, thinks he and his companies can simply ignore the Federal OSHA Bloodborne Pathogens Standard with regard to required condom use in his adult film productions shot in Nevada. This new complaint in Nevada is based on the simple fact that they cannot hide from federal law there, or anywhere in the U.S.,” said Michael Weinstein, President of AIDS Healthcare Foundation. “When we first proposed the Los Angeles City bill, the industry said they’d film in other L.A. cities. When we proposed Measure B for L.A. County, the industry said they’d film in other counties. And when we proposed AB 1576, the industry said they’d film outside of California. Here, Mr. Acworth will no doubt find out that both Nevada and Federal OSHA statutes apply as well. Are workers in Nevada any less entitled to protection from harm than those in California?”

ALSO RELATED: This week the AHF sued the city of San Francisco for blocking its plans to open a pharmacy in the Castro. According to the AHF, local AIDS activists are behind the denial because they are furious with the AHF for opposing the use of Truvada as a daily HIV preventive.

"At the behest of San Francisco Supervisor Scott Wiener, The City rammed through, at lightning speed, an interim zoning law specifically targeting AIDS Healthcare Foundation," claimed Laura Boudreau, chief of operations for AHF. "The clear and sole purpose of that action was to discourage the organization from relocating and opening a nonprofit safety-net clinic and pharmacy in the Castro." But City Attorney spokesman Matt Dorsey called the civil rights violation charge "absurd." "AHF is asking the court to find a constitutional right to build whatever it wants wherever it wants, and that's just not something courts have allowed," Dorsey said.

Boudreau claims the motivation for The City's actions came from the foundation's position on PrEP -- an HIV treatment drug which the Centers for Disease Control and Prevention and others have advocated for as a preventative tool, but which the group opposes as a widespread HIV prevention tool, arguing its efficacy is debatable. While a local HIV activist said the AHF's position on HIV prevention is not popular among many in San Francisco, he and Wiener point out that the main issue with the group, which has 33 locations nationwide, is that it operates a chain. The city's formula retail rules define chain stores as any with 11 or more locations. "AHF tried to game our formula retail law by tweaking its name and then claiming it wasn't actually formula retail," Wiener said. "Under AHF's approach, any chain store could come into San Francisco, tweak its name, and claim that it isn't formula retail."

New PReP Efficacy Study Released

A new study on the efficacy of Truvada as an daily HIV preventive was released yesterday at the International AIDS Conference in Melbourne, Australia. According the research, which was simultaneously published in The Lancet, missing an occasional daily dose does not increase the chance of infection, but the drug must be taken at least four times a week in order maintain a blood level that blocks HIV.

While the effectiveness of PrEP was first proven in 2010, there had been some concern that it might not be safe to use long term. There was also speculation that access to PrEP could either cause individuals to increase risky sexual behaviour or be reluctant to use it. But the latest study found no evidence of “risk compensation”. It also found that there was an interest and willingness to use the preventative method by those at high risk of HIV-infection.

Tested on more than 1 600 HIV-negative men, including gay men, bisexuals, transgender women and men-sleeping-with men (MSM) at 11 research sites on four different continents, the latest study found that PrEP provided 100 percent protection among participants who took the pill four times or more every week. Those who took the pill two or three times a week registered a protection rate of about 84 percent. Those who took fewer than two tablets in the same period had no protection at all.

Carried out by the US-based National Institute of Health over an 18-month period in Chicago, San Fransisco, Boston, Thailand, Rio de Janeiro and Cape Town, among other sites, researchers are convinced that using pre-exposure prophylaxis could save lives of high-risk populations. ay men are regarded as the key population or at highest risk of HIV infection and transmission. At the conference it also emerged that while the HIV/Aids burden was declining in parts of the world, HIV infection among gay men was increasing.

Here's another take from AIDS Map:

The group of gay men and transgender women in this study who elected to take a daily Truvada pill had half as many HIV infections (relative risk = 0.51) compared with a comparator group of people who elected to stay in the study but not to take PrEP. They also had half the HIV infection rate (relative risk = 0.49) of people in the placebo arm of the original iPrEx randomised controlled trial (RCT). As has been seen in other studies of pre-exposure prophylaxis (PrEP), as well as in the original iPrEx RCT, the primary determining factor when it came to the efficacy of PrEP was adherence.

All participants in iPrEx OLE had their level of adherence calculated from drug levels observed in blood samples. PrEP had so significant efficacy in people who took fewer than two doses a week. However, the efficacy of PrEP was 84% in people who took 2-3 doses a week – there was only one infection in this group – and no infections at all were seen in people taking at least four doses a week. This 100% efficacy translates into a minimum efficacy of 86% if the statistical uncertainty of the result is taken into account.

About That Truvada Study

Josh Barro writes for the New York Times:

The sample size (2,500 subjects, half taking a placebo) wasn’t large enough to establish that Truvada is 100 percent effective when taken daily, especially because only 18 percent of subjects who were given Truvada actually had the medication in their blood at levels that were consistent with daily use. But by looking at the handful of infections among people taking their pills less than daily, the iPrEx researchers were able to build a statistical model of how the risk of infection declines as the number of pills taken weekly rises. In 2012, they estimated that actually taking Truvada every day produces a 99 percent reduction in the risk of H.I.V. infection, despite not directly observing any such infections.

In an email, Dr. Robert Grant, a top H.I.V. researcher at the University of California at San Francisco and the lead investigator for the iPrEx study, called the 99 percent figure “our best estimate of the H.I.V. risk reduction when men and transgender women who have sex with men use PrEP daily.” (PrEP, or “pre-exposure prophylaxis,” is the practice of using antiviral medication like Truvada to prevent H.I.V. infection, rather than to treat it.) Dr. Grant noted that lower estimates, such as the 92 percent figure, include results for people who were not taking the drug daily.

Barro concludes: "Putting too much weight on the 99-percent figure may lead some PrEP users to perceive virtually zero H.I.V. risk when they should really be thinking about very low risk."