Treating COVID-19 with CRISPR, updated AstraZeneca advice

Scientists from Melbourne’s Peter Doherty Institute for Infection and Immunity (Doherty Institute) and Peter MacCallum Cancer Centre (Peter Mac) have found a way to stop the SARS-CoV-2 virus from replicating in infected human cells, in a major step towards a new treatment for this and future pandemic viruses.

Published in the journal Nature Communications, the discovery builds on research that started at Peter Mac in 2019, when Dr Mohamed Fareh and Professor Joe Trapani showed a CRISPR gene editing tool could be used to eliminate abnormal RNAs that drive children’s cancers. In collaboration with Director Professor Sharon Lewin and Dr Wei Zhao from the Doherty Institute, this same approach has been shown to suppress replication of the RNA virus SARS-CoV-2 — as well as its variants of concern — in a test tube model.

At the core of the tool is an enzyme (CRISPR-Cas13b) that binds to target RNAs and degrades part of the virus’s genome needed to replicate inside cells. According to Prof Lewin, “The flexibility of CRISPR-Cas13 — which only needs the viral sequence — means we can look to rapidly design antivirals for COVID-19 and any new emerging viruses.”

Dr Fareh said there were signs this approach — which the team will now move to test in animal studies — could also be applied to a host of existing viruses and be a game changer for how they are currently treated.

“Unlike conventional antiviral drugs, the power of this tool lies in its design flexibility and adaptability, which make it a suitable drug against a multitude of pathogenic viruses including influenza, Ebola and possibly HIV,” Dr Fareh said.

The release of the research coincides with the latest statement from the Australian Technical Advisory Group on Immunisation (ATAGI) on the use of the AstraZeneca COVID-19 vaccine. ATAGI maintains that the Pfizer vaccine is recommended for individuals under 60, but says in the context of a COVID-19 outbreak where access to Pfizer is limited, such as in Greater Sydney right now, adults younger than 60 should reassess the benefits of being vaccinated with AstraZeneca, versus the rare risk of a serious side effect.

In addition, ATAGI says that while the recommended interval between the first and second doses of AstraZeneca vaccine is between four and 12 weeks — offering the greatest efficacy at the 12-week mark — in outbreak situations an interval of between four and eight weeks is acceptable, as it will enable short-term protection. Therefore, people in an outbreak situation who received their first dose of AstraZeneca more than four weeks ago should contact their vaccine provider to arrange their second dose as soon as possible.

Image credit: ©stock.adobe.com/au/MiaStendal

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