COVID-19: How the University of Queensland vaccine failed because of HIV testing

The small bottles labeled with a “Vaccine COVID-19” sticker and a medical syringe are seen in this photo taken on April 10, 2020. Photo: Reuters / Dado Ruvic / Illustration

Australia’s hopes for a locally developed COVID-19 vaccine have been dashed with news today, the University of Queensland / CSL vaccine will not continue with other clinical trials.

Unlike the news about the Pfizer / BioNTech COVID vaccine earlier this week, there were no safety issues with the UQ / CSL vaccine.

According to a statement to the Australian Stock Exchange (ASX) earlier today, the CSL said participants in the phase 1 study received “false positive” HIV tests. They were not infected with HIV, nor did the vaccine contain the entire HIV virus.

Rather, the signature of the “molecular clamp” vaccine was formulated with parts of an HIV protein. When injected, they produced antibodies that were taken in a series of HIV tests. In other words, if the vaccine were launched on a large scale, this could lead many people to believe that they have HIV when they have not.

The news prompted the federal government to announce that it had canceled its agreement to supply the UQ / CSL vaccine, which was always conditional on the successful completion of clinical trials.

Instead, the government will provide more doses of other vaccines, including an additional 20 million doses of vaccine at Oxford / AstraZeneca University, which will be made by the CSL.

The COVID Oxford / AstraZeneca vaccine is the first with published results from phase 3 clinical trials, a significant step.

In addition to the Oxford / AstraZeneca vaccine, existing arrangements are in place to provide Pfizer / BioNTech and Novavax vaccines to Australians if they prove to be safe and effective. That is, as well as the vaccines available under the COVAX agreement supported by the World Health Organization.

How can a COVID vaccine lead to a positive HIV test?

The UQ / CSL vaccine uses “molecular clamp” technology to stop the coronavirus tip protein from “swaying”. This more stable presentation is more likely to lead to a protective immune response.

The molecular clip in the UQ vaccine contains part of an HIV protein, a string of 80 amino acids. In itself, this is harmless and cannot cause HIV or AIDS.

But there has always been a theoretical possibility that, once injected as part of the formulation of the vaccine, the human immune system would recognize it as “foreign” and grow antibodies against it. So far, the research team believes that the chances of this happening are low. And in its ASX statement, CSL said that the people in the process of 216 people were fully informed about this possibility.

However, from what we have heard today, it is clear that human immune systems have recognized the fragment of HIV protein in the molecular clamp.

If we had launched this vaccine on a larger scale, we would have seen more “false positive” HIV tests. This would have meant unnecessary anxiety, while people sought further clarification on their HIV status.

It would also undermine public confidence in the COVID vaccination program. You have to have the audience on board. Therefore, by acting early to clearly communicate concerns, the researchers acted accordingly. And this should strengthen public confidence in Australia’s COVID vaccination program, which will start in March 2021.

Is this the end of UQ technology with “molecular clamp”?

This special molecular clamp is unique to UQ. So while this particular type will not be used for future vaccines, researchers are likely to investigate and modify it to reduce the chance of possible cross-reactivity to HIV.

I certainly don’t think it’s the end of this technology.

So where does that leave us?

We know over time that not all COVID-19 vaccines in early clinical trials would be successful. Safety issues or lack of protection will stop some. But in this case, we had something different – a complication that would lead people to believe they have HIV when they don’t, undermining people’s confidence in the COVID vaccine program.

That is why it is still important to pursue a broad portfolio of vaccine approaches and technologies. We don’t want to put all the eggs in one basket.

It is also important to remember that although the UQ / CSL vaccine will not move to late-stage clinical trials, Phase 1 trials will continue, with results presented for timely peer review. This means that researchers can analyze the results in more detail.

Adam Taylor, Early Career Research Leader, Emerging Virus Groups, Inflammation and Therapies, Menzies Health Institute Queensland, Griffith University

This article is republished from Conversation under a Creative Commons license. Read the original article.