Lightnews — Scholar-powered news

Mhairi McCormack @mhairijan.bsky.social · Aug 7

Check out this CVR news article on our new paper! 🦠

MRC-UofG Centre for Virus Research @cvrinfo.bsky.social · Aug 6

📃 A Hidden Glitch: How HIV drugs can distort virus immunity tests

‪@mhairijan.bsky.social‬ & colleagues found a flaw in widely used virus immunity tests. HIV drugs can interfere with lab results, causing false positives that mislead our understanding of immune responses.

gla.ac.uk/research/az/...

Gloved hand holding a blood sample tube labelled "HIV" with checkboxes for negative and positive; the positive box is ticked. The tube has a red cap, and a blurred laboratory background with other sample tubes is visible, suggesting a clinical testing environment.

1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

13/
💥 Implications:
Many studies may have over-reported immunity in HIV prevalent populations
🧪 It’s time to rethink how we assess immune protection in people living with HIV.
📄 doi.org/10.1038/s415...
#HIV #Immunology #Neutralisation #COVID19 #HCV

Retrovirus-based pseudotyped virus neutralisation assays overestimate neutralising activity in sera from participants receiving integrase inhibitors - Scientific Reports

Scientific Reports - Retrovirus-based pseudotyped virus neutralisation assays overestimate neutralising activity in sera from participants receiving integrase inhibitors

doi.org

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

12/
📢 Bottom line:
If you’re measuring immune responses (neutralising antibodies) in HIV prevalent populations – or where ART is unknown:
❌ Avoid retrovirus-based assays
✅ Use VSV-based systems

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

11/
To further test this, we added antiretroviral drugs directly to the assay 🧪
Result? Adding dolutegravir to the assays triggered false positives 🚨
Additionally, when we extracted the antibodies from the serum and tested directly, these false positives vanished

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

10/
In the UK cohort, those on integrase inhibitors (like dolutegravir) showed falsely higher immune responses when using retroviral-based PVNAs:
💊 Integrase inhibitors: 71.8%
🚫 Others: 21.3%
Unfortunately, we didn’t have ART data for the Malawi cohort 🤷

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

9/
So what was causing the interference? 🔍
We looked at participants’ antiretroviral therapy (ART) medication stats — and saw one major clue 💊

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

8/
To dig deeper, we used HIV and MLV ‘cores’ with a different outer ‘wrapper’ (VSV-G)
🎯 Result? Still high neutralisation – even though no one had known VSV exposure
✅ This confirmed the interference was from the retrovirus ‘core’ itself!

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

7/
We re-tested using vesicular stomatitis virus(VSV) core PVNAs (i.e., non-retroviral), and saw a dramatic drop in immune response:
Malawi study:
📉 >90% → 20-49%
UK study:
📉 34% → 14%
😈 Something was interfering with the retrovirus-based assays 😈

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

6/
⚠️This was unexpected: HIV lowers people’s immune responses to viruses – that’s why it’s so dangerous
❓But our results showed the opposite: people with HIV responded better to the virus!
So we asked:
Could the assay itself be causing false signals? 🤨

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

5/
In both, we saw better immune responses (% neutralisation) in people with HIV – which didn’t add up 🤔
Malawi SARS-CoV-2 study:
🧍‍♂️ HIV uninfected: 22-32%
🧍‍♂️ HIV infected: >90%
UK HCV study:
🧍‍♂️ HIV uninfected: )0%
🧍‍♂️ HIV infected: 34%

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

4/
We used these retrovirus core assays in two separate studies, both based in HIV-prevalent populations:
🇲🇼 Malawian communities looking at SARS-CoV-2 using an HIV core assay
🇬🇧 UK patients with HCV studying immune responses to HCV with an MLV core assay

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

3/
🛡️PVNAs wrap the safer ‘core’ of a modified virus with the outer ‘wrapper’ of a more dangerous one. This lets scientists experiment on dangerous viruses safely
🦠 We used retrovirus cores, with the most commonly used cores being HIV and MLV (murine leukaemia virus)

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

2/
🧪 Scientists use pseudovirus neutralisation assays (PVNAs) to safely measure neutralising antibodies – a key indicator of the immune response to viruses. This means that the virus we use in the lab is different to the real virus
⚠️ And that’s where the problems begin…

1 1

Mhairi McCormack @mhairijan.bsky.social · Aug 6

🚨Are we overestimating viral immunity in people with HIV?🚨
In our new study, we found that a widely used lab test might give false positives for people with HIV who are on certain types of medication (integrase inhibitors)
Here’s what we found 🧵1/n

1 3 5

Mhairi McCormack @mhairijan.bsky.social · May 16

Thrilled to share my first first-author paper is now published!

Detailing SARS-CoV-2 immune responses in Scottish healthcare settings, this is an important insight into current population immunity.

#SARSCoV2 #Immunology #PhD

www.sciencedirect.com/science/arti...

Estimating population immunity to SARS-CoV-2 by random sampling from primary and secondary healthcare in Scotland, May 2024

As the COVID-19 pandemic has ended, the global focus has shifted from “pandemic response” to “long-term management”. With no ongoing nationwide serosu…

www.sciencedirect.com

4

Mhairi McCormack @mhairijan.bsky.social · Mar 28

Had a wonderful time in Oxford this week filled with data modelling, presentations, meetings, and beautiful lunch spots! Huge thanks to @jameshay.bsky.social for inviting me down and all the wonderful researchers who have taken the time to speak with me #PhD #BigData @ox.ac.uk

3

Mhairi McCormack @mhairijan.bsky.social · Mar 25

Thrilled to be visiting the Big Data Institute in Oxford this week to collaborate with data modellers on analysis for my PhD project! 🖥️🦠 #PhD #BigData #epidemiology

4

Mhairi McCormack @mhairijan.bsky.social · Feb 5

Had an incredible time at #RTI2025 this week where I presented my poster on #SARSCoV2 in #Malawi! Nothing beats seeing my Sankey plots up on the Science Centre IMAX screen - data visualisation on a whole new level! 🦠 🇲🇼

1 3

Reposted by Mhairi McCormack

Antonia Ho @drtoniho.bsky.social · Feb 4

Great turnout from the @cvrinfo.bsky.social Clinical Viral Epidemiology Group at #RTI2025. 🦠🫁

@mhairijan.bsky.social & Elen Vink presenting their #PhD work tomorrow.

3 7