Vaccination brought to mind, strangely, thoughts on ambidexterity. When one arm feels a bit leaden after a jab, how does one go about doing with the other, that which seems impossible. As per research, being born ambidextrous can be disadvantageous for cognitive functioning, especially for arithmetic, memory retrieval, and logical reasoning, besides it has been associated with difficulties in language too. Yet, it isn’t clear if training towards ambidexterity would also cause the same issues as being born ambidextrous does 
On a positive note, it is quite possible to train ones non dominant hand to become more proficient, as in a concert pianist skilled with both hands, but whose mastery is complementary rather than competitive . Some random thoughts at a vaccination and a poem thereafter …
You are one step closer, say stickers in red,
on a floor burning it's way to needles.
Unpeopled lines criss cross, one to medication
another to a woman in a white lab coat
against a wall, papered to impress or assure ,
etched in beakers, pipettes, bunsen
burners in blue. Here, swabs, syringes
and two arms to choose from.
"Which do you prefer", she asks, seated
at my left and I look to my right
at my BCG scar. Suddenly, this
seems painfully sore. "Left", I say,
besides, "you are closer", I think.
My right arm needs to lift the dutch oven
and to write, brush my teeth, chop onions
for biryani and ouch, there aren't any tears
only a needle I felt, like her unsmiling or resigned
face. She must feel tired poking dozens
of people for no fault of their own
so I wished her a great day and all that,
then took my place on a seat among
people moping over their big bright
phones, for my fifteen minutes of pain
or not, as I am distracted easily and this
is a pharmacy. Here I am in the section for adult diapers
with a vantage view of incontinence. Que sorte!
Read further: ~https://www.theguardian.com/education/2016/sep/03/can-you-boost-your-brain-power-by-making-yourself-ambidextrous