This week, the biotech company Moderna will start human trials for its HIV vaccine. Its HIV vaccine will be the first of its kind to use messenger RNA (mRNA), an approach that Moderna used in its effective COVID-19 vaccine.
The clinical trials will start on August 19 and end sometime around spring 2023, according to the National Institutes of Health’s trial registry. They will involve 56 HIV-negative participants aged 18 to 56. The participants will be given one or two forms of mRNA that cause the body to form defenses against HIV infection.
Related: Here’s why COVID-19 has a vaccine after 1 year and HIV doesn’t after nearly 40 years
In the past, HIV vaccines used inactivated forms of the virus. However, previous trials showed that these forms didn’t produce any immune responses. In fact, researchers canceled one trial in Thailand during the 2000s after inactivated forms of the virus were found to actually increase people’s risk of catching HIV rather than preventing infections.
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Instead, the Moderna trials will contain one of two different types of mRNA: mRNA-1644 and mRNA-1644v2. These get the body’s cells to develop a “protein spike” on their surfaces. These spikes are similar to those embedded by HIV on a cell’s surface when it begins to infect cells to reproduce. When the body recognizes the presence of the mRNA spike, it begins producing antibodies to protect against infection.
The mRNA may also allow scientists to make tweaks to the vaccine more easily.
“The mRNA platform makes it easy to develop vaccines against variants because it just requires an update to the coding sequences in the mRNA that code for the variant,” Rajesh Gandhi, MD, an infectious diseases physician at Massachusetts General Hospital and chair of the HIV Medicine Association, told the medical site Verywell.
This is especially helpful for HIV since the virus is known for having mutated into at least 16 known variants.
Moderna’s mRNA vaccines passed Phase I testing earlier this year. Phase I trials test safety by administering different dose strengths and observing how the body and drug interact. Phase II trials test the vaccine’s overall effectiveness, and Phase III trials will compare the safety and effectiveness of the new vaccine against the current HIV prevention medications.
If the vaccine successfully completes Phase III testing, then Moderna can submit its studies for approval by the U.S. Food and Drug Administration (FDA). Then, the FDA will conduct Phase IV trials for widespread testing and cost analysis.
If successful, the vaccine could then become widely available, helping end an epidemic that has ravaged the globe for over 40 years.
