The Australian government has abandoned a promising domestic Covid-19 vaccine developed by the University of Queensland and biotech firm CSL after participants in an early-stage clinical trial falsely tested positive for HIV.
Highlighting potential setbacks faced by scientists in efforts to bring safe and effective vaccines to market.
While there is no chance that the vaccine could cause an HIV infection — something detailed follow-up tests confirmed — scientists warned participants that the vaccine could possibly generate a partial immune response to a protein fragment used to stabilize the vaccine, which is also found in HIV.
Scientists said the magnitude of the immune response was “unexpected,” to the point that it was able to interfere with HIV tests that detect antibodies, and give false positives.
The vaccine actually produced a “robust response towards the (Covid-19) virus and has a strong safety profile,” but Department of Health secretary Brendan Murphy said the issue could cause “confusion” and undermine public confidence in the vaccine.
Moreover, the University of Queensland said “significant changes would need to be made to well-established HIV testing procedures in the healthcare setting to accommodate rollout of this vaccine,” leading the government to cancel its order of 51 million doses, while CSL shelved its plans to progress the vaccine to more extensive Phase 2 and 3 clinical trials.
Professor Paul Young, who co-led the research, said that although the issue could probably be fixed, “doing so would set back development by another 12 or so months,” time that cannot be justified given the current coronavirus crisis.
While certainly a blow, this kind of setback will mean less in Australia than if it happened elsewhere. The country has largely managed to bring Covid-19 to heel and, as a result, is rolling out vaccines at a much more sedate pace than the emergency approvals starting to be seen elsewhere, most notably with Pfizer-BioNTech’s vaccine in Canada and the U.K..
Australia has already moved to secure enough doses from other suppliers to replace the order it cancelled and Prime Minister Scott Morrison says the vaccination schedule remains unchanged as CSL will simply start manufacturing its rivals sooner.
This is not the first time a Covid-19 vaccine has given cause to worry about HIV. In October, a group of researchers warned that some vaccines currently in development could cause an increased risk of recipients acquiring HIV.