Introducing Long-Lasting HIV Prevention Methods
Pre-exposure prophylaxis (PrEP) is an innovative strategy aimed at preventing the human immunodeficiency virus (HIV) through the use of antiretroviral medications prior to potential exposure to the virus. Traditionally, in Mexico, PrEP has been administered mainly in the form of daily pills. However, a significant shift is on the horizon as the Federal Commission for the Protection against Sanitary Risks (Cofepris) has granted health registration to lenacapavir, a long-acting alternative that provides protection for up to six months.
This marks the first semi-annual PrEP option approved in the country. The decision follows the World Health Organization (WHO) recommending lenacapavir in July 2025 as an additional preventive measure against HIV. The WHO asserts that a biannual injection could help alleviate barriers such as the challenges of adhering to a daily medication regimen, stigma, and difficulties in accessing health services consistently.
From Daily Pills to Biannual Injections
Currently, Mexico offers daily oral PrEP regimens, along with a method known as event-driven PrEP, where pills are taken before and after potential exposure during sexual activity, rather than daily. According to the National Centre for the Prevention and Control of HIV/AIDS and Hepatitis (Censida), approximately 29,000 individuals received PrEP in 2025, although not all maintained continuous use throughout the year.
Lenacapavir introduces a different approach. Administered via a subcutaneous injection, it targets the HIV capsid, a structure that safeguards the virus’s genetic material and plays a role in various stages of its replication. Its formulation allows the medication to remain active for several months following each injection.
While oral PrEP is highly effective when taken as prescribed, some individuals may find it challenging to maintain a consistent medication schedule. Forgetfulness, changes in routine, difficulties obtaining the medication, or concerns about privacy can hinder prevention efforts. This is why the WHO emphasises the importance of broadening the available options, enabling individuals to choose the method that best suits their personal circumstances.
Understanding the Effectiveness of Lenacapavir
The approval of lenacapavir is primarily supported by two phase 3 clinical trials funded by Gilead Sciences, the pharmaceutical company behind its development. The first trial, named PURPOSE 1, involved adolescents and young women in South Africa and Uganda and compared the semi-annual injection to two oral PrEP regimens.
Results published in The New England Journal of Medicine revealed that none of the 2,134 participants receiving lenacapavir contracted HIV during the study period. In contrast, the groups using other oral PrEP regimens reported 39 infections among those treated with emtricitabine and tenofovir alafenamide, and 16 among those taking emtricitabine and tenofovir disoproxil fumarate.
This finding was further validated in a more diverse population through the PURPOSE 2 trial, which included cisgender men, women, transgender individuals, and non-binary persons. Among the 2,183 participants who received lenacapavir, only two HIV infections were recorded, representing a 96% reduction in incidence compared to a reference population with similar characteristics.
Ensuring Continuous Medical Support
It is crucial to note that receiving an injection every six months does not eliminate the need for medical follow-up. Prior to receiving lenacapavir, individuals must confirm their HIV-negative status through testing, and these tests should be repeated before subsequent injections.
This precaution is essential, as the medication is intended as a preventive measure for those without HIV. If an individual were to contract the virus and continue solely with lenacapavir, there is a risk that the virus could develop resistance to the drug, complicating future treatment options. Consequently, the WHO has updated its recommendations to facilitate the use of rapid tests before initiating and during the continuation of long-acting injectable PrEP.
Furthermore, lenacapavir does not provide protection against other sexually transmitted infections (STIs). It should be seen as part of a comprehensive prevention strategy that may include condom use, regular testing, and the diagnosis and treatment of other STIs, tailored to individual needs.
The Challenge of Accessibility
The approval from Cofepris represents only a portion of the journey ahead. While the agency now permits the use of lenacapavir as PrEP in Mexico, the announcement lacks details regarding its pricing, commercial availability, and whether it will be immediately integrated into public health services.
Cost has emerged as a central issue surrounding this medication. UNAIDS has cautioned that the potential of long-acting treatments will significantly depend on their affordability, particularly in countries where new HIV infections continue to occur.
In 2025, agreements were announced for the production of generic versions of lenacapavir intended for low- and middle-income countries. However, Mexico has been excluded from some of these access schemes, alongside other Latin American nations. This exclusion raises concerns about the pricing of the medication in the country.
Mexico already possesses a framework for delivering PrEP. In January 2026, Censida updated its guidelines for providing PrEP and post-exposure prophylaxis (PEP), laying the groundwork for incorporating this new preventive option. Achieving this will require securing the procurement of the medication, training healthcare personnel, ensuring necessary testing, and monitoring those who receive injections.
Having demonstrated its efficacy in thousands of individuals, the next step for Mexico is to transform this health authorisation into a practical prevention tool that effectively reaches those in need.