TL;DR
Researchers are developing CRISPR-Cas13 systems delivered by lipid nanoparticles as a potential flu antiviral, aiming to cut viral RNA and block replication in infected respiratory cells. Early lab work including lung-on-chip experiments showed suppression of multiple flu strains with no observed off-target effects in that model, but experts warn delivery, immune responses and viral evolution remain significant hurdles.
What happened
At a recent scientific meeting, investigators from the Peter Doherty Institute and collaborators outlined a program to repurpose CRISPR for influenza control. Rather than the DNA-targeting Cas9, they focus on Cas13, an RNA-directed enzyme that can be programmed to slice viral RNA. The proposed therapy would use lipid nanoparticles to carry two molecular components: an mRNA that tells cells to produce Cas13, and guide RNAs that direct Cas13 to conserved segments of influenza’s genome. Delivered as a nasal spray or injection, the approach is intended both to treat active infections by halting viral replication and to act prophylactically by prearming respiratory cells. Independent work at Harvard’s Wyss Institute used human lung-on-chip models to test Cas13-expressing cells and reported suppression of diverse strains including H1N1 and H3N2 without detectable off-target damage in that system. Researchers caution the strategy is early-stage: immune reactions to a bacterial enzyme, dosing and getting particles into deep lung tissue, and the possibility of viral escape all remain open questions.
Why it matters
- Cas13 targets RNA, so it could directly disable influenza viruses whose genomes are RNA-based.
- Engineering guides toward conserved viral regions could produce treatments effective across many flu strains.
- A successful antiviral that works across strains would address limits of current drugs that face rapid resistance.
- Influenza A causes substantial annual mortality in the U.S., underlining demand for more effective therapeutics.
Key facts
- Cas13 is an RNA-targeting CRISPR enzyme; Cas9 primarily edits DNA.
- Proposed delivery uses lipid nanoparticles carrying an mRNA that encodes Cas13 plus guide RNAs to target viral sequences.
- The delivery formats discussed include a nasal spray or an injection aimed at respiratory tract cells.
- Wyss Institute lung-on-chip experiments reported suppression of H1N1 and H3N2 replication with no observed off-target effects in that model.
- Researchers aim guide RNAs at 'conserved regions' of influenza RNA—segments present across many strains and important to the virus.
- Other pan-influenza strategies mentioned include monoclonal antibodies and drugs that boost interferon responses.
- Experts have raised safety concerns including potential immune responses to Cas13 and the risk of unintended targeting of host RNA.
- Delivering lipid nanoparticles deep into alveolar cells in the lungs is identified as a significant technical challenge.
- Researchers are also exploring Cas9-based approaches to reduce expression of host genes influenza depends on, including work implicating SLC35A1.
What to watch next
- Progress toward human clinical trials of Cas13-based antivirals — not confirmed in the source.
- Results of in vivo delivery studies that show whether lipid nanoparticles can reach alveoli efficiently — not confirmed in the source.
- Safety data on immune responses to Cas13 and any off-target effects in animal or human studies — not confirmed in the source.
Quick glossary
- CRISPR: A set of genetic tools derived from microbial immune systems that can be programmed to target specific DNA or RNA sequences.
- Cas13: A CRISPR-associated enzyme that recognizes and cleaves RNA molecules, which can be directed by a guide RNA.
- Lipid nanoparticles (LNPs): Small, fat-based carriers used to deliver nucleic acids like mRNA into cells.
- Guide RNA: A short RNA molecule that directs a CRISPR enzyme to a specific genetic sequence for targeting.
- Conserved region: A segment of a virus’s genetic code that remains similar across multiple strains and is often important for the virus’s survival.
Reader FAQ
Is the Cas13 approach ready for people?
Not confirmed in the source.
How would Cas13 stop influenza?
Cas13 can be programmed with guide RNA to cut viral RNA, disrupting the virus’s ability to replicate in infected cells.
Have safety risks been observed?
In lung-on-chip tests researchers reported no off-target effects in that model, but experts caution immune reactions and delivery challenges remain concerns.
Could this replace vaccines?
Not confirmed in the source.
DAVID COX SCIENCE JAN 5, 2026 5:00 AM Flu Is Relentless. Crispr Might Be Able to Shut It Down Innovative research into the gene-editing tool targets influenza’s ability to replicate—stopping…
Sources
- Flu Is Relentless. Crispr Might Be Able to Shut It Down
- Progress in CRISPR/CAS13-Mediated Suppression of …
- CRISPR therapy shows promise against influenza in …
- Molecular Scissors Could Help Keep Some Viral Illnesses …
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