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Pfizer vaccine - low blood glucose?

LittleGreyCat

LittleGreyCat

Well-Known Member
Retired Moderator
There is a long thread about high BG after Covid vaccination.

I've just had my second jab.
I ate very low carb and my BG kept on going down.
Not alarmingly so, but steady.
I was woken up by my Libre 2 alarm when dropping off around 23h:00 with a 3.2.
I put this down to lying on the sensor.
BG came back up soon after.
However I had another alarm around 02:00 (lying on sensor again) then my Libre 2 had a hissy fit and refused to scan.
Looking at the numbers my BG had been steadily trending lower, well below 5, so I decided to have a yoghurt and some jam just in case.

After rebooting my phone, again just in case, I managed to scan and my BG was up like a rocket.
Blank half hour or so when the sensor wouldn't read.

All fine and well but this morning I didn't get the usual DP and my BG is trending down again.
I won't know for another few hours but I'm wondering if this is a side effect of the vaccine.
I'm still on just Metformin so no glucose lowering medication to blame.
Oh, and my knees hurt.
 
LittleGreyCat said:
There is a long thread about high BG after Covid vaccination.

I've just had my second jab.
I ate very low carb and my BG kept on going down.
Not alarmingly so, but steady.
I was woken up by my Libre 2 alarm when dropping off around 23h:00 with a 3.2.
I put this down to lying on the sensor.
BG came back up soon after.
However I had another alarm around 02:00 (lying on sensor again) then my Libre 2 had a hissy fit and refused to scan.
Looking at the numbers my BG had been steadily trending lower, well below 5, so I decided to have a yoghurt and some jam just in case.

After rebooting my phone, again just in case, I managed to scan and my BG was up like a rocket.
Blank half hour or so when the sensor wouldn't read.

All fine and well but this morning I didn't get the usual DP and my BG is trending down again.
I won't know for another few hours but I'm wondering if this is a side effect of the vaccine.
I'm still on just Metformin so no glucose lowering medication to blame.
Oh, and my knees hurt.
Click to expand...
Have you confirmed the libre readings with a meter?
 
I have only had one jab and it was not Pfizer.
However, I too found my insulin needs decrease significantly for the next 3 days.
Yes, I did check Libre with finger pricks and, no, I am not alone with this reaction.
 
My first Astra-Zeneca jab just happened to coincide with my first Libre in months. :D
The vaccine certainly made my bg much less stable, and more irregular. Normal (for me) food choices resulted in a v unusual jangly Libre graph scrambling about all over the place for nearly 3 days.
Several bigger than usual highs and then v mild hypos, whereas I would normally have had much less variation.

if I hadn’t been wearing the Libre I might only have noticed a bit more energy fluctuation and fatigue and some odd hunger pangs.

(I'm not on any meds for blood glucose control)
 
Last edited:
Not my experience. I've had both fizzers from Pfizer. I am on Metformin and a small dose of Gliclazide and noticed no significant change in fingerprick readings.
 
Thanks to all so far.
Interesting that others are seeing BG drops or lower insulin requirements.
As I said up top the big thread was about raised BG,
 
LittleGreyCat said:
Not in the last couple of days.
Click to expand...

Hi,

As confident as i am using the Libre. I always back up a blip with a finger prick. :)

If you have low BG episodes regularly with your diet choice to help manage your diabetes too. & the downward trend continues.
It maybe worth a review with your doctor regarding the meds.?

Best wishes.
 
If you think there is a connection to the vaccine, then raise a yellow card for it. Let them find out if it is a worry using their reporting system.
 
HSSS said:
Have you confirmed the libre readings with a meter?
Click to expand...
Good spot.
Last time I had low readings with a previous Libre 2 I checked and it was spot on.
This time I assumed that it would be more or less correct and two checks showed BG 2 full units higher, then (after the sensor refused to scan again) shows BG 1.5 units higher than the sensor.

Which as a side issue no doubt messes with my predicted HbA1c.

I will stick with this sensor for the moment but it is looking suspect.
 
When I had my first AZ jab I had low BGs the same day. It was helpful for the takeaway I had for my tea that night :) The day after I had higher BGs. I haven't had my second jab yet.
 
After some low readings and unreliability from the Libre 2 the monitoring has settled down and finger pricks seem to more or less match the sensor readings.

I am now running determinedly high, at around 30-40% in range and very sensitive to minor carbohydrate indiscretions.

Hopefully this will settle down soon but I am finding it both irritating and disruptive.
If it carries on then I may Yellow Card it.
 
Hi to all,

I had a phone call yesterday to say my second injection is next saturday i am not having it made my arm really painfull & also set my bowel problem off so now need another colonscopy yuck and made all my joints really painfull too.

They said i can still have it later if i want too No.

Sparklebright62.
 
Sparklebrightisright62 said:
Hi to all,

I had a phone call yesterday to say my second injection is next saturday i am not having it made my arm really painfull & also set my bowel problem off so now need another colonscopy yuck and made all my joints really painfull too.

They said i can still have it later if i want too No.

Sparklebright62.
Click to expand...

Hi Sparklebright,

This topic is primarily regarding low BGs as a result of the "jab." (All be it possibly a tempary side effect?)

Your side effect seems a little more of a personal nature.
Would you like me or a member of the Mod team to take your post & make your own topic.?
You may find others with the same experience, rather than your issues get lost in the this thread..

Best wishes.
 
For about 4 days after the Pfizer jab I had hypos at unexpected times - woke up really low which is unlike me. Pulled back on insulin obviously but I'm on Tresiba which isn't that quick to react.

Second jab soon so will be interesting to see what hapoens
 
I was advised when I had my first Pfizer that they'd seen a blood sugar lowering effect in some diabetics. No one mentioned a word about it when I had my second one.
 
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