Severe Lung Lesions After Inoculation With Omicron BA1 In Vivo Warrants Surveillance Of Rapidly Spreading BA2
0 media coverage on this must be saying something......
On March 15th 2022, a new study out of the Netherlands was released. Essentially, it revealed substantial pathology in deep lung tissue of Syrian hamsters that were immunized with Omicron BA.1. Below, slides have been created for you that simplify the data. So, in this publication you will learn:
The pertinent details of this study
The implications of this data for you
The data
First understand, the data from this study will be broken down into bullet points so you can better understand the corresponding slides. If you’d rather read a brief summary, (although the entire 25 page document should be analyzed to ensure proper understanding) it will be listed immediately below.
THE TAKEAWAY: Syrian hamsters exposed to BA.1 Omicron variant having no previous immunity experienced substantial lung pathology. That evidenced by multiple focal areas covering 50-90% of lung surface appearing dark red, slightly raised, and well-delimited (well defined) at 5 days dpi (days post inoculation). In other words, multiple foci seen suggest an increased proclivity for cancer cell development & other pathologies of affected areas.
Moving on, now each slide will be broken down.
Slide 1
These were materials & methods used to execute the experiment
Delta, Omicron, and Bavpat- 1 614G strains (SEEN IN LEFT COLUMN) were propagated to passage 3 on previously mentioned Calu-3 cells to create more virus that would be used to inoculate hamsters in this trial. Said virus and cells were first supplemented with DMEM/F12, HEPES, Glutamax, penicillin, and streptomycin then incubated and harvested for 72 hours
Then Calu-3 immortal cells (SEEN IN MIDDLE COLUMN) were cultured in a growth medium (food to sustain cells) called Opti-MEM I + Glutamax. Also, Calu-3 cells were supplemented with FBS (fetal bovine serum- another growth supplement), penicillin & streptomycin (to ensure no bacterial growth and minimal loss of valuable cells)
The result of both columns 1+2 was column 3 seen on the far right. That said, all produced virus was then centrifuged in order to clear supernatant (liquid above solid material) and then prepared for administration to hamsters
Slide 2
This was the experiment and how it was carried out
4 total groups of hamsters:
GROUP 1- To be infected with Delta (n=8 SARS-CoV-2 naive hamsters)
GROUP 2- To be infected with Omicron (n=8 SARS-CoV-2 naive hamsters)
GROUP 3- PREVIOUSLY infected with ancestral strain 614G (n=4), but to be reinfected with Omicron 13 days after 614G exposure
GROUP 4- MOCK/PBS group (n=4) acting as a control only to receive phosphate buffered salient instead of virus
All groups NASALLY challenged with the virus
RESULTS FOR DELTA EXPOSED HAMSTERS: Average of 78% of lung area affected as evidenced by foci formation. Also 14% reduction in body weight peaking at 4-5 dpo (days post inoculation)
RESULTS FOR OMICRON EXPOSED HAMSTERS: Multiple focal areas covering 50-90% of lung surface appearing dark red, slightly raised, and well-delimited (well defined) at 5 days dpi (days post inoculation). Such pathology suggests malignancy or progression to other pathology
RESULTS FOR PREVIOUSLY INFECTED (WITH 614G), THEN REINFECTED WITH OMICRON HAMSTERS: No weight-loss, no lung or nasal turbinate pathology seen. Also, re-challange with Omicron revealed substantially less infectious viral load in nose, throat, and lungs
RESULTS FOR CONTROL GROUP SPRAYED WITH PCB INSTEAD OF VIRUS: NO CHANGE
Slide 3
Graphical summaries of results from each group
Nasal washes collected at days 1,3,5,7,10,14,18 & 21 revealed that infectious virus was found for up to day 3 in the nose
Throat swabs done on animals at days 1,3,5,7,10,14,18 & 21 revealed lower amounts of infectious virus with Omicron VS Delta infection at day 1
Nasal turbinate, trachea & lung samples collected from 1 hamster in each group which were sacrificed on the 5th day. Notably, substantial lung damage was observed in Omicron infected hamsters, and lesser damage seen in Delta infected hamsters. Remaining animals were sacrificed by day 26
Weight of hamsters was measured everyday for 10 days. Interestingly, a large 14% weight loss was observed in those exposed to Delta which peaked at day 4+5, while no loss was observed in naive immune then omicron exposed hamsters. The same applied to hamsters previously exposed to 614G then re-exposed to Omicron- no weight loss observed
Slide 4
This slide specifies the lung tissue pathology experienced by hamsters exposed to Delta or Omicron
Exposure to Delta: Nearly 78% of lung tissue became inflamed after being nasally challenged with propagated Delta virus. Also, there was a small focal area noted on the lower left lobe
Exposure to Omicron: Multiple focal areas covering up to 90% of lung surface appearing dark red, slightly raised, and well-delimited (well defined) at 5 days dpi
Some final words
There were some confounding variables in this study.
First, CALU-3 cells used were from an immortal line. Meaning, given the right amount of sustenance, they could grow inevitably. To that point, pathologies could possibly continue at a higher rate compared to other cells.
Second, this experiment was done in-vivo, meaning, in a multicellular organism, in this case hamsters-not humans. In other words, it could be difficult to derive value from these results as animals are not the same as human. So, further studies in humans are essential
Third, the susceptibility of Syrian hamsters to carcinogens may make them more likely to develop tumors compared to other hamsters.
Finally, the length of this experiment may have been too short. Said differently, the data didn’t show if lung pathology became worse or better because of time constraints (21 days). Also, deep lung pathology was only observed after virus infected the live hamsters at 5 days but no longer than that.
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