Moderna will soon begin the first-ever human clinical trials for a messenger RNA-based HIV vaccine, utilizing the same technology as its COVID vaccine. The trials could potentially begin as soon as this week, though they have not started recruiting as of publication time.
Moderna will recruit 56 HIV-negative adults to enroll in Phase I. It will be testing two mRNA-based vaccines. Moderna’s and Pfizer’s COVID vaccines are mRNA-based, while Johnson & Johnson’s is not.
In the 37 years since HIV was identified as the virus that causes AIDS, no vaccine against it has ever been approved. That’s not for lack of trying: Five HIV vaccines have made it through clinical trials as far as Phase 3, the final step toward the Food and Drug Administration approving a drug as safe and effective.
But three of those five failed to protect from infection. The fourth vaccine, RV144, was developed in Thailand and was deemed only about 31 percent effective. A fifth attempted to follow up RV1444’s progress, but ultimately proved ineffective, too. Each initiative cost over $100 million.
The variability of HIV in a single person can be higher than the variability of a seasonal flu virus across the entire world.
A significant barrier is the complexity of the virus itself. “HIV is continually evolving within a single infected individual to stay one step ahead of the immune responses,” Ronald C. Desrosiers, a pathology professor at the University of Miami, wrote in The Conversation. “[T]hrough natural selection a mutated virus variant appears that is no longer recognized by the individual’s immune system. The result is continuous unrelenting viral replication.”
So the HIV virus can become highly variable within the same human body. The variability of the HIV virus in a single person can be higher than the variability of a seasonal influenza virus across the entire world.
The United Nations Programme on HIV/AIDS estimated that in 2020, close to 38 million people globally were living with HIV, and 1.5 million became newly infected. More than 36 million people have died of AIDS-related complications since the epidemic began in the 1980s.
Currently, sub-Saharan Africa is the part of the world hardest hit by the virus. Lesotho, South Africa, and Mozambique lead the world in deaths from HIV by population. HIV is the leading cause of death in South Africa, Mozambique and Botswana.
The US federal government spends over $28 billion per year responding to HIV/AIDS, spread between prevention, care, research and mandatory spending on programs like Medicare and Medicaid. Overall, US expenditures on HIV/AIDS have risen over the past 30 years—but have remained flat since 2010, and are actually declining when adjusted for inflation. Private investment reached a high of $680 million in 2016, but is concentrated in a small pool that primarily funds research.
Meanwhile, local governments across the country are increasingly targeting syringe service programs that have helped keep HIV prevalence under control, even as historic outbreaks emerge and new clusters are identified across multiple states. Many are also increasing police funding, despite policing itself being associated with spikes in HIV.
Advocates hope that in addition to breaking new ground on a vaccine, the pandemic will catalyze more drastic political action.